THAI NGUYEN UNIVERSITY OF AGRICULTURE AND FORESTRY
NATIONAL TSING HUA UNIVERSITY

GRADUATE REPORT
Title:
"The Use soil as the adsorbent to understand the capacity
toward copper ions adsorption"
Full name
: Luu Thi Thuy Linh
Class
: K42AEP
Supervisor
: Prof. RueyAnDoong
Dr. Nguyen Thanh Hai
Taiwan - 2014
i
ACKNOWLEDGMENT
First of all, I would like to express sincere thanks to the school board Thai Nguyen
University of Agriculture and Forestry, Faculty of International Training and
Development; advanced program, thank the teachers who has imparted to me the
knowledge and valuable experience during the process of learning and researching here.
In the process of implementing and completing thesis, I have received the enthusiastic
help of the teachers of National Tsing Hua University. I would like to express my special
thanks to Prof. Ruey An Doong who has spent a lot of time, created favorable conditions,
enthusiastic to guide me to complete this thesis.
I sincerely thank my friends in the laboratory facilitated, and provided the
information and data necessary for my implementation process and helped me finish this
thesis.
In the process of implementing the project, due to time, financial and research
levels of myself is limited so this project is inevitable shortcomings. So, I would like to
receive the attention and feedback from teachers and friends to this thesis is more
complete.
I sincerely thank you!
Taiwan, 2014
Students perform
Luu Thi Thuy Linh
2
Table of Contents
LIST OF TABLES ............................................................................................................ iii
LIST OF FIGURES .......................................................................................................... iv
LIST OF ABBREVIATIONS ........................................................................................... v
1. INTRODUCTION ......................................................................................................... 1
2. LITERATURE REVIEW ............................................................................................. 3
2.1 The value of tea ............................................................................................................ 3
2.1.1 Nutritional Value ....................................................................................................... 4
2.1.2 The value of medicinal .............................................................................................. 6
2.1.3 The value of Economic .............................................................................................. 7
2.2 The role of nutrients for tea ........................................................................................ 9
2.3 Role of copper in tea .................................................................................................. 11
2.3.1 Function of Copper: ................................................................................................ 12
2.3.2 Deficiency Symptoms: ............................................................................................. 13
2.3.3 Toxicity ..................................................................................................................... 14
2.4 Researches about the absorption of soil .................................................................. 15
2.4.1 Application of Natural Clayey Soil as Adsorbent for the Removal of Copper from
Wastewater ....................................................................................................................... 15
2.4.2 Calcareous Soil as a New Adsorbent to Remove Lead from Aqueous Solution:
Equilibrium, Kinetic and Thermodynamic Study ........................................................... 15
2.4.3 Adsorption of arsenic from aqueous solution on naturally available red soil ..... 16
3. RESEARCH METHODS ........................................................................................... 20
3.1 Objectives: .................................................................................................................. 20
3.2 Location: ..................................................................................................................... 20
3.3 Project Content: ......................................................................................................... 20
3.4 Methodology: ............................................................................................................. 20
4. RESULTS ..................................................................................................................... 27
4.1 Soil properties ............................................................................................................ 27
4.1.1 Size of soil sample:................................................................................................... 27
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4.1.2. Soil Organic Matter (SOM), pH of soil: ................................................................ 28
4.2 Adsorption .................................................................................................................. 32
5. DISCUSSION AND CONCLUSION ......................................................................... 34
6. REFERENCES ............................................................................................................ 36
APPENDICES ................................................................................................................. 38
ii
LIST OF TABLES
Table 1: Layers with different size....................................................................................21
Table2: Classification of soil particles in the USSR........................................................21
Table 3: The group of lower concentration .......................................................................24
Table 4: The group of higher concentration......................................................................25
Table 5: Size of soil sample...............................................................................................27
Table 6: Absorption of copper ions in the soil after 24 hours at lower concentrations ....32
Table7: Absorption of copper ions in the soil after 24 hours at higher concentrations.... 33
iii
LIST OF FIGURES
Fig.1: XRD diffractogram studies of red soil................................................................17
Fig.2: Effect of adsorbent dose on As (III) adsorption (C0 = 1.0 mg l-1, pH: 7.2, shaker
speed: 130rpm) ..................................................................................................................18
Fig.3: Effect of pH of solution on As (III) adsorption C0 = 1.0 mg l-1, adsorbent dose:
25g l-1, shaker speed: 130rpm............................................................................................19
Fig.4 OM process .........................................................................................................28
Fig.5: Absorption of copper ions in the soil after 24 hours at lower
concentrations....................................................................................................................32
Fig.6: Absorption of copper ions in the soil after 24 hours at higher concentrations 33
iv
LIST OF ABBREVIATIONS
Temp.
Temperature
Cu
Copper
US
United State
EU
Eropean Union
OM
Organic Matter
N
Nitrogen
P
Photphorus
Z
Zinc
XRD
X-ray diffraction
USSR
Union of Soviet Socialist Republics
TOC
Total Organic Carbon
LOI
Loss on ignition
Conc.
Concentration
DI water
Deionized water
AAS
Atomic Absorption Spectrometry
SOM
Soil Organic Matter
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Thai Nguyen University of Agriculture and Forestry
Degree Program: Bachelor of Environmental Science and Management
Student name: Luu Thi Thuy Linh
Student ID: DTN 1053110124
Thesis Title: The Use soil as the adsorbent to understand the capacity toward copper
ions adsorption
Supervisor (s): Prof. Ruey An Doong
Dr. Nguyen Thanh Hai
Abstract:
Soil adsorption and plant adsorption are synergistic. It has a major role for the plant.
This research assesses the role of tea in soil ‘s absorption of copper. They aremetal elements
necessary for tea, they affect the growth of leaves and buds, in ethylene sensing, cell wall
metabolism, oxidative stress protection and biogenesis of molybdenum cofactor. The
topics also evaluates soil’s properties and their role for tea as well as the impact insoil’s
absorption capacity. Specifically, the soil type is "fine clay", it needs to use filters with
multiple different sizes to accurately assess soil properties. This soil type has high flexibility,
good moisture retention, increased absorption capacity of the soil. Thevalue of "OM" is
measured by Loss on ignition (LOI), Total Organic Carbon (TOC) accounted for 9.34%,
which is high value. They provide essential nutrients for tea, and promote the absorption sale
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of soil. However, the pH value of the soil is low, only 4.7, this value is appropriate with the
tea, but it reduces the absorption capacity of the soil. The ability of soil to absorb increased
copper concentration increases, however, this value is very low, only about 7% to 14% for
concentrations of 0.1 to 3. The method used was Atomic Absorption Spectrometry (AAS ),
here is the testing machine, which gets the fastest and most accurate result of the
concentration. The explanation for this problem may be that the influence of pH is major, but
there was not enough time to conduct research with higher concentrations. It hadto be
evaluated in subjects with low concentrations. It means low ability to absorb copper that
increases with increasing concentration but value is low.
Keywords: Adsorption, Copper(II), soil, tea
Number of pages: 39
Date of Submision: January 15th
vii
1. INTRODUCTION
Tea is one of the major export products of Vietnam. At present, Vietnam tea
producing area ranked 5th and the 7th largest output in the world, tea products are
available in 92 countries around the globe. The tea markets for Vietnam are Middle East,
South Asia, Eastern Europe, Taiwan. [4]
Thai Nguyen is a mountainous province in the North Midlands, with favorable
natural conditions of climate, soil, potential agricultural and forestry development. Thai
Nguyen’s tea has a long tradition. In particular, Tan Cuong tea is famous in the whole
country and is considered to have high quality and safety.
However, Vietnam's tea is considered to underperform compared to with its
potential. Its yield is lower than that of other placesin the world. Moreover, the quality
and competitiveness of the Vietnamese tea products are low and unstable. Difficulties
such as technical standards, product quality, food safety, and convenience are significant.
This situation is due to many causes such as the low level of intensive farming, the
cultivation techniques, rapidly changing natural conditions and ecology as well as
volatitle economic conditions and market requirements for higher quality.
The best quality of tea is affected by cultivation methods, climate, soil quality,
nutrient requirements. In particular, soil and nutrient have close relationships with each
1
other. The capacity of soil to store nutrientsand supply for tea is important in maintaining
good and lasting quality.
Thus it is important to assess this capability of planting soil, and apply it to tea
cultivation techniques, in order to provide guaranteed quality tea products. At the same
time, it can contribute information about the soil. In this case, copper is selected as a
proxy to evaluate the absorption capacity of the soil. The reason is its essential role with
tea, and copper is the metal that soil can absorb quite strong. Therefore, I propose
Research: "The Use soil as the adsorbent to understand the capacity toward copper ions
adsorption"
2
2. LITERATURE REVIEW
2.1 The value of tea
Tea is a crop brings economic benefits, an ideal drink has many medicinal values,
besides planting, the tea processing is also a long-standing culture of the traditional
Vietnamese until now.
According to the study of biology, Vietnam is one of the homeland of tea in the
world. Tea is a perennial plant, with long-term economic life, high economic efficiency.
Tea planting once, can be harvested 30-40 years or longer. Nowadays the world has
about 40 tea cultivation countries. Tea is cultivated most concentrated in Asia, then to
Africa. [1]
Tea cultivation in Vietnam has been a long time, but tea is planted and exploited in
a large area was began more than 50 years. In plantations of tea, tea is the main source of
income, contributing significantly to improve and enhance the life of people. The
production and provided of tea can satisfy demand for the domestic and export demand.
Because of that, compared with other crops in Vietnam, tea is one of the most dominant
trees in both climate and labor resources.
Due to the condition of land and suitable climate, so the tea is planted scattered in
most mountainous and midland provinces of Vietnam. In the south, the tea is planted
mainly in the provinces of Lam Dong and Gia Lai, in the north, the provinces of Thai
Nguyen, Phu Tho, Tuyen Quang, Son La, Ha Giang, Yen Bai and Lao Cai...
3
At present, Vietnam is a country ranked 5th in the world for the production and
export of tea, after India, China, Kenya, Sri Lanka, and on par with Indonesia.
2.1.1 Nutritional Value
The nutritional components in tea include amino acids, vitamins, minerals,
hydratcarbon, protid and lipid. [6]
a. Amino acids
A major component in the organization of human cells is protid; in which amino
acid is the composition of protid. There are 25 kinds of amino acids in the human body,
including 8 types that the human body can not synthesize, must rely on outside food
supplements.
Free amino acid content in tea is 2-5%. Amino acids effects with human
physiology as cardiac, diuretic, blood vessel relaxation bloom...
b. Vitamin
Vitamins are organic compounds essential for metabolic processes in the human
body. It is a coenzyme participating nutrient composition as protid, lipid, glucide.
Although the body only needs a very small amount, but humans can not create, so need to
supplements from foods as the external suppliers.
In fresh tea leaves have more vitamins. Vitamin can soluble in lipids (such as A1,
A2, D1, D2, D3, D4, K1, K2) and vitamin soluble in water (such as B1, B2, B6, B12, PP,
4
pantotenic, C, P). For the vitamin soluble in water, when mixing tea with boiling water,
can extracted up to 80% vitamin.
c. Minerals
Minerals are indispensable quality of the human body; some kinds can participate
in tissue composition and skeletal muscle; some kind involved in maintaining osmotic,
acid-base balance and metabolism in the body. In tea has more than 40 minerals,
including macro elements such as K, Ca, Na, P, Mg, Cl and secondary and trace elements
such as Si, Fl, Al, Cd, Fe, Mn, Co, Zn, Se, As, Mo ...
If want to determine the mineral composition of tea, must determine the
composition of the the ashes of tea. Ashes is the material remaining after tea calcined at
high temperatures of 500-600 ° C. Ashes divided into 2 groups, soluble and insoluble in
water. Groups that do not dissolve in water again divided into 2 small groups , soluble
and insoluble in dilute hydrochloric acid.
d. The glucide (hydratcarbon)
Glucide is a kind of nutrients mainly for humans, to maintain a stable body
temperature. Glucide is a group of organic compounds important and common in plants.
Glucide content accounted 85-90% in many plants, but in the tea leaves are low, not
exceeding 20% by weight of dry matter, this drink contain less sugar, suitable for people
with diabetes.
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2.1.2 The value of medicinal
Tea is a crop to bring economic benefits, an ideal drink has many medicinal
values.[2] Here are a few utility to drink tea:
1. Tea can reduce tired, promote metabolism, maintain the function of the heart,
blood vessel, gastric.
2. Tea effective in preventing tooth decay, according to the documents of the
United Kingdom, children drinking tea can reduce tooth decay up to 60%.
3. In the tea consists of trace elements is useful to human body.
4. Tea leaves have the effect of inhibiting melanoma. Drink tea to control the
growth of cancer cells.
5. Drink tea to control cell aging, anti-aging effects of tea leaves is more than 18
times with the vitamin E.
6. Drinking tea helps excitement of the central nervous system, strengthening
advocacy.
7. Drinking tea against obesity, especially green tea has the obvious effect,
enhance beauty.
8. Drinking tea destroys bacteria, prevention is sinusitis, sore throat, intestines.
9. Drinking tea protects hematopoietic function. In tea leaves contains antiradiation. Drinking tea while watching television will reduce the impact of radiation from
monitor, protect eyesight.
10. Drinking tea maintain balance acidity and alkalinity in the blood.
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11. Tea can prevent crush, drinking hot tea after 9 minutes, skin temperature
decrease 1 2ºC, makes the body cool, refreshing.
2.1.3 The value of Economic
In term of tea production for export, Vietnam is ranked 5th in the export of tea.
Recently, the competent authorities have agreed directives about branding Vietnamese
tea, including Tan Cuong tea is part of that brand. Vietnamese tea brand will be protected
in 77 countries and territories worldwide. The branding Vietnamese tea has a very
important role and increasing the value and competitiveness of Vietnam's tea products[4]
Currently, the area of specialty tea in the commune has grown to more than 300
ha; some production facilities, large tea business in commune like Tien Yen, Huong
Thang, Tien Dat... has annual revenues billion per year from processing and specialty tea
business.
Usually income from tea to the average value over 120 million / ha / year and now
has more than 200 households with incomes from 100 million / year from the production
of tea. This year, Tan Cuong has achieved new standards of rural communities have very
large contribution from tea plants [1]
To promote the potential strength of tea, Thai Nguyen city is planning to expand
the tea growing areas in Tan Cuong include communes as Tan Cuong, Phuc Triu, Phuc
Xuan with a total area of about 1,300 hectares of tea; in which more than 1,000 hectares
7
of tea business, the average production about 14,000 tons / year, the value of hundreds of
billion of income [4]
At Dai Tu district, some communes as Hung Son, La Bang Phu Thinh Phu
Xuyen... has increased to more than 5.400ha tea area, mainly the new tea varieties, high
quality, yield nearly 50,000 tons / year, reached the value of income from 80 to 100
million / ha / year.[1]
From craft of making tea, the province has more than 30 manufacturing
enterprises, trading and export of tea, more than 80 villages was recognized. Although
there are more than 80% of processed in traditional crafts but for about 3 years now,
every year, the exporting enterprises of tea reached more than 10 million dollars profit.[1]
Some tea regions like Tan Cuong, Phuc Xuan (Thai Nguyen City), La Bang (Dai Tu),
Trai Cau (Lap Minh, Dong Hy), Tuc Tranh (Phu Luong) ... has produced some tea
products of high value with prices ranging from 600,000 to 2,500,000 VND / kg dry tea
leaves, consumption market are quite stable[5]
In addition to contributing to the economy through export of tea, still brings the
contribution due to tourism. Foreign tourists like to visit the area of Thai Nguyen tea.
Every year, Thai Nguyen also attracted tens of thousands of tourists to the tea village. So
we can see the role of tea is huge for the economy of Vietnam.
Besides the advantages of tea, there exist many weaknesses as products of
Vietnam's tea exports with low quality, there are many defects and no credibility on the
8
world market. The average selling price is only 50-70% the world tea. Exports to major
markets such as the US, EU, Japan has a low price. [5]
The question is, why our tea has a lower price, difficult to develop in major
markets.
Thus, to improve the price of tea in Vietnam, we have to produce high quality tea.
The quality of tea depends on many different factors, including the requirements for
nutrients is the most important
2.2 The role of nutrients for tea
Tea is grown mainly from grafted branch, the new tea varieties are cultivated well,
it can productive over 3 tons of dried buds / ha / year. With such a large of biomass, tea
also requires a large amount of nutrients.
* Nutritional requirements: The study results showed that: To get the dry tea
leaves 2 tons / ha, nutrient requirements for tea are as follows: 144kg N; 71kg P2O5; 42
kg K2O; 24kg MgO; 40 kg CaO; 4.828g Fe; 9.557g Mn; 760g Zn; 760g Cu and 520g B.
When the yield up to 3 tons of dry buds/ha, the nutritional requirements for tea will
increase 2 times the amount of nutrients listed above. [7]
Thus, macronutrients requirement for tea including nitrogen (N) greater than 2
times the phosphorus (P2O5) and more than 4 times potassium (K2O), and also need to
the secondary nutrients such as Mg, Ca, and micronutrients such as Fe, Mn, Zn, Cu, B ...
* Nutrient requirements for Nitrogen: Nitrogen is a nutrient factors leading to
improved productivity of tea. Provide adequate protein, fast-growing of tea stems, leaves,
9
bud, budding, sprouting in the leaf axils.[11] Without Nitrogen, the tea will be stunted,
branches, leaves less developed, less shoots and buds, low productivity.
* Nutritional requirements for phosphate: phosphate has an important role for the
growth and development of tea. Phosphate promote the development of the roots of tea
from newly planted time to entering the production phase and phosphate are also
involved in the synthesis of nutrients for growth and development of tea and for the buds
and leaves.
Phosphate also involved in the process of accumulation of dissolved minerals in
the water. Lack of phosphate, tea will slow growth, poor branching capability. The
process of re-creating small roots delayed absorption leads to poor nutrition, make tea
yield unstable.
* Nutritional requirements for potassium: comparison with N and P are both less
abundant potassium, but potassium roles are very important for the rapid transport of
nutrients from the soil to photosynthesis and synthesis nutrition, especially in the buds
and young leaves, potassium also regulate the balance of nitrogen in tea. Without
potassium, tea will be weak, slow down growth, disease resistance poor. The results of
the study of inorganic fertilizers showed rate N: P: K suitable is 2.0: 1.0: 0.5, depending
on the soil conditions in each region. [3]
* Nutritional requirements for calcium: Although tea appropriate with pH from 4.5
to 5, but the fact, tea-planting soil in the northern mountainous provinces are mostly very
acidic, with a pH <4, so calcium have an important role in reducing acidic, creating an
10
environment suitable to the requirements of the land of tea, while also participating
synthetic nutrients for tea growing.[3]
* Nutritional requirements for magnesium: Mg has a particularly important role to
improve the efficiency of photosynthesis, tea have large biomass, mainly in buds and
leaves, so the new chlorophyll determines yield and quality tea. Without magnesium, less
leaves tea, little buds, and little foil, usually dark green leaves, small buds leads to poor
yield. Mg enough for tea will make increasing of chlorophyll, making the tea
development of many buds, leaves thick, shiny, accumulation of nutrients in the buds,
increase productivity and quality tea.
* Nutritional requirements for micronutrients including zinc, iron, manganese,
copper and bo ... effective participation of the enzyme structure to catalyze the formation
of minerals, vitamin compounds in buds and leaves, decided to the taste and quality of
tea. If there are deficiency of micronutrients will make a decline in the tea quality. [3][7]
Recognizing that, although tea need a small amount of copper, but the role of
copper is important for the tea
2.3 Role of copper in tea
Copper is an essential metal for tea. It plays key roles in photosynthetic and
respiratory electron transport chains, in ethylene sensing, cell wall metabolism, oxidative
stress protection and biogenesis of molybdenum cofactor. Thus, a deficiency in the
copper supply can alter essential functions in metabolism. However, copper has
traditionally been used in agriculture as an antifungal agent, and it is also extensively
released into the environment by human activities that often cause environmental
11
pollution.[15] Accordingly, excess copper is present in certain regions and environments,
and exposure to such can be potentially toxic to tea, causing phytotoxicity by the
formation of reactive oxygen radicals that damage cells, or by the interaction with
proteins impairing key cellular processes, inactivating enzymes and disturbing protein
structure.
2.3.1 Function of Copper:
Copper is an important component of proteins found in the enzymes that regulate
the rate of many biochemical reactions in tea. Tea would not grow without the presence
of these specific enzymes. There are some functions of Copper[15]:
- Promotes seed production and formation
- Plays an essential role in chlorophyll formation
- It functions as a catalyst in photosynthesis and respiration.
- It is a constituent of several enzyme systems involved in building and converting
amino acids to proteins.
- Copper is important in carbohydrate and protein metabolism.
- It is important to the formation of lignin in cell walls which contributes to the
structural strength of the cells.
- Copper affects the flavor, the storage ability, and the sugar content of tea.
Factors Affecting Availability [9]

Root Growth: Copper is the most immobile micronutrient, therefore anything
that inhibits new root growth will inhibit Cu uptake.
12

Soil pH: Acid soils increase Cu uptake and High pH inhibits uptake.

Organic Matter: Copper is readily and tightly complexed by organic matter,
therefore high soil organic matter levels reduce Cu availability.

Flooding: Waterlogged soils can reduce Cu availability while they are saturated,
however after they are drained the Cu will become available again.

Cu: Zn Balance: High Zn levels will reduce Cu availability.

Cu: N Balance: High N uptake in the presence of marginal Cu levels can lead to
a reduction of Cu transport into the growing tips of tea.

Cu: P Balance: High soil and tea P levels can reduce Cu uptake due to reduced
soil exploration by mycorrhizas associated with tea roots.

N Stress: Low N availability decreases the vigor of tea to an extent that it may
fail to take up adequate amounts of many other nutrients. Copper uptake can be affected
in this way.
2.3.2 Deficiency Symptoms:
Symptoms vary depending on the crop. Typically the symptoms start as cupping
and a slight chlorosis of either the whole leaf or between the veins of the new leaves.
Within the chlorotic areas of the leaf, small necrotic spots may form, especially on the
leaf margins. As the symptoms progress, the newest leaves are smaller in size, lose their
sheen and in some cases the leaves may wilt. The death of the growing points often leads
to excessive tillering in cereal crops and excessive branching in dicots (non-grass crops).
In some case show a blue-green color before advancing to chlorosis. Excessive wilting,
lodging and reduced disease resistance result from the weak cell walls caused by Cu
13
deficiency. The apical meristems may become necrotic and die inhibiting the growth of
lateral branches. Flower color is often lighter than normal. Copper is found to be evenly
distributed in the plant, but is relatively immobile. Therefore, a constant supply is needed
throughout the growing season.[15]
Excess potassium, phosphorus or other micronutrients can indirectly cause copper
deficiency. Also if the pH of the growing medium is high, this can induce a copper
deficiency as it is less available for tea uptake.
2.3.3 Toxicity
Excess copper in the growing medium can restrict root growth by burning the root
tips and thereby causing excess lateral root growth. High levels of copper can compete
with the uptake of iron and sometimes molybdenum or zinc. The new growth can
become initially greener than normal, then exhibit symptoms of iron deficiency or
possibly other micronutrient deficiencies. If not corrected, copper toxicity can reduce
branching and eventually plant decline follows. [13]
Copper, like most micronutrients is more available when the growing medium pH
is low, so if copper toxicity is occurring, test the pH of the growing medium. [8] Also
certain fungicides have copper as their active ingredient, so it is essential to rinse the
foliage off before testing the tissue.
With the roles mentioned above, copper (Cu) contributed much to the growth of
tea and bring good quality. In the other hand, soil and tea has nutrient relationship with
14
each other. The ability of soil to absorb copper as possible, the tea has been providing
longevity and efficiency. [15]
Absorption capacity of the soil is assessed with many different properties of soil.
In which, each factor has a very important role to absorption, and the role of tea. Many
articles, research about absorption capacity of different metals of different types of soil.
Each soil has its own properties and has the different absorb ability for different
substances. To do good research, the articles references and relevant contribution to the
experimental methods and different results, great support in the process of doing research.
2.4 Researches about the absorption of soil
2.4.1 Application of Natural Clayey Soil as Adsorbent for the Removal of
Copper from Wastewater [18]
Use of clayey soil has been explored in the laboratory scale experiment as a low
cost adsorbent for the removal of copper from wastewater. The influence of metal ion
concentration, weight of adsorbent, stirring rates, influence of temperature, pH are also
evaluated and the results are fitted using adsorption isotherm models. From the
experimental results it is observed that almost 90–99% copper can be removed from the
solution using clay at optimized pH 5.5
2.4.2 Calcareous Soil as a New Adsorbent to Remove Lead from Aqueous
Solution: Equilibrium, Kinetic and Thermodynamic Study[17]
Natural calcareous soil of Indian origin was tested and evaluated as a possible
adsorbent for removal of lead from its aqueous solution using batch sorption technique.
The adsorption process is also dependent on numerous factors such as the solution pH,
15
adsorbent dosage, temperature, stirring rate, initial Pb (II) concentration and contact time.
The percentage removal of lead ions decreased with an increase in the lead concentration
while it increased with increase in contact time and adsorbent dose upto a certain level.
The maximum removal was found at pH 6.0. Equilibrium data fitted very well in the
Langmuir isotherm equation, confirming the monolayer adsorption capacity of Pb(II)
ions onto calcareous soil with a monolayer adsorption capacity of 2.34 mg/g at 313 K.
According to Dubinin-Radushkevich (D-R) isotherm model, adsorption of lead onto
calcareous soil was chemisorption. The adsorption kinetics followed pseudo-secondorder kinetic model with a good correlation. Intra-particle diffusion was not the sole rate
controlling factor. The activation energy of the adsorption process (Ea) was found to be 34.64kJmol-1 by using the Arrhenius equation, indicating exotherrmic nature of lead
adsorption onto calcareous soil. Thermodynamic analysis suggests that the removal of
lead from aqueous solution by calcareous soil was a spontaneous and exothermic process.
A comparison between the ANN model simulated results and the experimental data gave
high correlation coefficient (R2 = 0.959). Therefore the present findings suggest that
calcareous soil may be used as an inexpensive and effective adsorbent without any
treatment or any other modification for the removal of lead ions from aqueous solutions.
2.4.3 Adsorption of arsenic from aqueous solution on naturally available red
soil [10]
Arsenate and arsenite removal from naturally available red soil in and around
Western Ghats of Maharashtra near Mumbai has been investigated. The parameters like
adsorbent dose, operating pH, contact time, initial arsenite concentration, adsorbent
16
particle size, etc. on the removal of arsenite and arsenate are examined. Kinetic study in
centrifuge vessel reveals that uptake of As (III) ions is rapid in the first two hours and
slows down thereafter. Maximum removal efficiency of As (III) achieved is 98% at an
adsorbent dose of 45 g l-1 with initial As (III) concentration of 1000 µg l-1 in batch
studies and 95% at 25 g l-1 absorbent dose under the same conditions. Equilibrium time
is almost independent of initial arsenite concentration. Equilibrium studies show that As
(III) ions have high affinity towards red soil even at very low concentration of arsenite. In
speciation study, about 25% conversion to As (V) from As (III) is observed, with initial
As (III) concentration of 1000 µgl -1 and at 25 g l-1 adsorbent dose. The results suggest
that red soil could be used as effective filter medium for removal of arsenic from water.
Fig.1: XRD diffractogram studies of red soil
17
Fig.2: Effect of adsorbent dose on As (III) adsorption (C0 = 1.0 mg l-1, pH:
7.2, shaker speed: 130rpm)
Figure 2 shows the effect of adsorbent dose on percentage removal of As (III)
The figure reveals that uptake of As (III) increases rapidly from 5 to 25 g l-1, and
marginally thereafter due to more surface area with increase in adsorbent dose (Gupta
et al., 2005). Further increment of adsorbent does not affect much due to
nonavailability of adsorbate. In the subsequent studies, the adsorbent dose selected was
25 g l-1. This will help to carry out pilot studies in the field for arsenic removal from
ground water. Effect of particle size on adsorption of As (III) having concentration of
1.0 mg l-1 is very small
18
Fig.3: Effect of pH of solution on As (III) adsorption C0 = 1.0 mg l-1,
adsorbent dose: 25g l-1, shaker speed: 130rpm
Effect of pH of the solution: Fig. 3 shows the effect of pH on adsorption of
As (III) and percentage removal of As (III). From the figure, it is evident that about
92% of As (III) was adsorbed on the red soil surface in a pH range of 4.0-10 at an
initial As (III) concentration of 1.0 mg l-1. The percentage removal decreases
rapidly with further increase in pH. As (III) adsorption on red soil surface was
almost pH independent in the range of 4-10, with slight higher adsorption in the
acidic pH range. At higher pH (>9.8), laterite surface is negatively charged and
arsenite adsorption becomes less due to repulsion of similar charge, as arsenite
exists as anion in that pH range. Similarly maximum adsorption was observed for
As (III) adsorption in the pH range 7-7.6 on activated alumina (Singh and Pant,
2004) and iron-oxide coated sand (Gupta et al., 2005) as both iron and aluminium
oxide present in the red soil are primarily responsible for arsenite adsorption.
19
3. RESEARCH METHODS
3.1 Objectives:
- Water samples containing copper ions with different concentrations
- Soil samples used as absorber: tea- planting soil in Tan Cuong, Thai Nguyen,
Viet Nam
3.2 Location:
- Soil samples location: Tan Cuong commune, Thai Nguyen city.
- Location for doing research: Department of Biomedical Engineering and
Environmental Sciences, National Tsing Hua University, Taiwan
- Time: from September to December 2014
3.3 Project Content:
- Determine the size of the soil
- Determination of soil organic, pH of soil
- Determine the capacity to absorb metal ions Cu2+
3.4 Methodology:
* Soil sieve method to know the soil type
Using filters with 6 layers, with membranes of different sizes, classified from
largest to smallest. The particle size classified as follows:
20
Table 1: Layers with different size
#
Size
#10
2000µm
#60
0,250 µm
#100
0,149 µm
#230
0,062 µm
#325
0,044 µm
Sieve soil layers, then take notes the results of each layer and compare with the
following table to know what kind of soil.
Table 2: Classification of soil particles in the USSR
Particle diameter (µm)
Name of fraction
> 3000
Stone
3000 - 1000
Gravel
1000 - 500
Coarse sand
500 - 250
Medium sand
250 - 50
Fine sand
50 - 10
Coarse silt
10 – 5
Medium silt
21
5–1
Fine silt
1 – 0,5
Coarse clay
0,5 – 0,1
Fine clay
< 0,01
Colloid
• Methods of determining pH:
Take 2g soil samples mixed with 10 ml of distilled water, shaken, deposition by
centrifugation for 5 minutes, taking the aqueous and then measure the pH with pH meter
instrument.
• Method of determining the amount of organic matter in soil
In soils:
Total Carbon = Inorganic Carbon + Organic Carbon (1)
TOC content can be measured directly or can be determined by difference if the
total carbon content and inorganic carbon contents are measured. For soils and sediments
where no inorganic carbon forms are present, Equation (1) becomes:
Total Carbon = Organic Carbon
The basic principle for the quantitation of total organic carbon relies on the
destruction of organic matter present in the soil or sediment although there are a few nondestructive techniques identified in the literature that are currently under development.
22
The destruction of the organic matter can be performed chemically or via heat at elevated
temperatures. All carbon forms in the sample are converted to CO2 which is then
measured directly or indirectly and converted to total organic carbon or total carbon
content, based on the presence of inorganic carbonates.
The loss-on-ignition (LOI) method for the determination of organic matter
involves the heated destruction of all organic matter in the soil. A known weight of
sample is placed in a ceramic crucible (or similar vessel) which is then heated to between
3500 and 4400C overnight (Blume et al., 1990; Nelson and Sommers, 1996; ASTM,
2000). The sample is then cooled in a desiccator and weighed. Organic matter content is
calculated as the difference between the initial and final sample weights divided by the
initial sample weight times 100%. All weights should be corrected for moisture/water
content prior to organic matter content calculation. [10]
Experiment:
Take 2g soil samples and place in 1 porcelain vases were cleaned with ethanol,
porcelain vases put into the furnace in the temperature of 550 degrees C for 2 hours.
After the process is finished, measure the amount of soil remaining in porcelain vases and
compared with the original amount.
* Absorption methods
Preparation of copper stock solution:
+ Prepare buffer to control the pH = 7 of solution (available in the laboratory)
23
+ Dissolve 89,7mg (using weighed on an analytical balance) of Cu(NO3)2 in
250ml buffer
+ After we have stock solution of Cu2+ (Cu(NO3)2). Take 50ml is the final volume.
Selection of different concentrations: To test the different concentration levels and
convenient to comparison, I divided into two groups as follows concentrations:
*Calculate the volume of the stock solution based on the concentration of the final
volume (50 ml):
100 x M1 = M2 x 50
Which: M1 is stock solution (Cu(NO3)2)
M2 is concentration (selected)
Table 3: The group of lower concentration
Conc. (µM)
Stock solution (ml)
DI water (ml)
0,1
0,05
49,95
0,2
0,1
49,9
0,5
0,25
49,75
1
0,5
49,5
1,25
0,625
49,675
24
Table 4: The group of higher concentration
Conc. (µM)
Stock solution (ml)
DI water (ml)
1
0,5
49,5
1,5
0,75
49,25
2
1
49
2,5
1,25
48,75
3
1,5
48,5
+ After preparation of the samples, using AAS to determine concentration of copper
element. This method was selected because it is the fastest.
* Atomic Absorption Spectrometry (AAS) is a technique for measuring quantities of
chemical elements present in environmental samples by measuring the absorbed radiation
by the chemical element of interest. This is done by reading the spectra produced when
the sample is excited by radiation. The atoms absorb ultraviolet or visible light and make
transitions to higher energy levels. Atomic absorption methods measure the amount of
energy in the form of photons of light that are absorbed by the sample. A detector
measures the wavelengths of light transmitted by the sample, and compares them to the
wavelengths which originally passed through the sample. A signal processor then
integrates the changes in wavelength absorbed, which appear in the readout as peaks of
energy absorption at discrete wavelengths.
25
The concentration is calculated based on the Beer-Lambert law. Absorbance is
directly proportional to the concentration of the analyte absorbed for the existing set of
conditions. The concentration is usually determined from a calibration curve, obtained
using standards of known concentration.
In analytical chemistry, AAS is a technique used mostly for determining the
concentration of a particular metal element within a sample. AAS can be used to analyze
the concentration of over 62 different metals in a solution. [16]
+ Each sample, take 1g of soil, shake and wait 24 hours, then check the
concentration for the result. To measure correct result, right experimental methods, when
measuring samples with ASS machine must be fluid and no solids or cloudiness. So, after
24 hours, the sample will be separated from soil by sedimentation and filtration.
26
4. RESULTS
4.1 Soil properties
4.1.1 Size of soil sample:
Highly dispersive soil particles play an essential role in all the interphase
interactions in soils: ion-exchange adsorption. Therefore, the assessment of the effect of
the particle-size distribution on the adsorption properties of soils is a vital task (Aslanov
and Ryzhov, 1969)
Table 5: Size of soil sample
#
Size
Weigh (g)
Percentage (%)
#10
2000µm
11,577
3,3
#60
0,250 µm
119,441
34,8
#100
0,149 µm
137,012
40
#230
0,062 µm
54,317
15,8
#325
0,044 µm
19,688
6,1
Total of weigh: 343 (g)
100
Compare with the classification of soil particles by diameter that has been adopted
in the USSR (Table 2)
27
In the results, particle size of soil was almost in the range from 0.5 to 0.1 (60%).
To compare with Table 5, the major soil here is "fine clay." soil particle size smaller, the
more flexible and higher activity, enhances the absorption of soil metals
4.1.2. Soil Organic Matter (SOM), pH of soil:
* OM:
*Calculate the OM of soil:
600
550
2 hours
500
400
Temp. 300
(oC) 200
1 hour
100
30'
0
0
Temp.
30
30
50
100
150
200
250
300
Time (minute)
Fig.4 OM process
It is necessary to convert the organic matter content to total organic carbon
content. Traditionally, for soils, a conversion factor of 1.724 has been used to convert
organic matter to organic carbon based on the assumption that organic matter contains
58% organic C (i.e., g organic matter/l .724 = g organic C)(Nelson and Sommers, 1996).
However, there is no universal conversion factor as the factor varies from soil to soil,
28
from soil horizon to soil horizon within the same soil, and will vary depending upon the
type of organic matter present in the sample. Conversion factors range from 1.724 to as
high as 2.5 (Nelson and Sommers, 1996; Soil Survey Laboratory Methods Manual,
1992). Broadbent (1953) recommended the use of 1.9 and 2.5 to convert organic matter
to total organic carbon for surface and subsurface soils, respectively.
The process of determining organic matter experiments were done in 270 minutes,
the initial sample weight is 2g, end of the experiment, the remaining sample weight is
1,891g, losing weight is 0,109g (percent 5,45%) are considered "total organic carbon"
Organicmatter (%) = Total organic carbon (%) x 1,724
= 5,45 x 1,724 = 9,34 (%)
2% Organic matter is poor. Over 4% O.M. to 10% is ideal (Carl Rosat– Soil
Consultant). With this ideal "SOM", will bring advantages for tea, specifically:
Organic matter contributes to plant growth through its effect on the physical,
chemical, and biological properties of the soil.
Availability of nutrients for tea growth
Organic matter has both a direct and indirect effect on the availability of nutrients
for tea growth. In addition to serving as a source of N, P, S through its mineralization by
soil microorganisms, organic matter influences the supply of nutrients from other sources
(for example, organic matter is required as an energy source for N-fixing bacteria).
29
A factor that needs to be taken into consideration in evaluating humus as a source
of nutrient is the cropping history. When soils are first placed under cultivation, the
humus content generally declines over a period of 10 to 30 years until a new equilibrum
level is attained[11]. At equilibrium, any nutrients liberated by microbial activity must be
compensated for by incorporation of equal amounts into newly formed humus.
Effect on soil physical condition, soil erosion and soil buffering and exchange
capacity
Humus has a profound effect on the structure of many soils. The deterioration of
structure that accompanies intensive tillage is usually less severe in soils adequately
supplied with humus. When humus is lost, soils tend to become hard, compact and
cloddy. Aeration, water-holding capacity and permeability are all favorably affected by
humus. The frequent addition of easily decomposable organic residues leads to the
synthesis of complex organic compounds that bind soil particles into structural units
called aggregates[14] These aggregates help to maintain a loose, open, granular
condition. Water is the better able to infiltrate and percolate downward through the soil.
The roots of tea need a continual supply of O2 in order to respire and grow. Large pores
permit better exchange of gases between soil and atmosphere.
Humus usually increases the ability of the soil to resist erosion. First, it enables the
soil to hold more water. Even more important is its effect in promoting soil granulation
and thus maintaining large pores through which water can enter and percolate
downward.[19]
30
Effect on soil biological condition
Organic matter serves as a source of energy for both macro- and macrofaunal
organisms.
Numbers of bacteria, actinomycetes and fungi in the soil are related in a general
way to humus content. Earthworms and other faunal organisms are strongly affected by
the quantity of plant residue material returned to the soil.[11][19]
Organic substances in soil can have a direct physiological effect on tea growth.
Some compounds, such as certain phenolic acids, have phytotoxic properties; others, such
as the auxins, enhance plant growth.
It is widely known that many of the factors influencing the incidence of
pathogenic organisms in soil are directly or indirectly influenced by organic matter. For
example, a plentiful supply of organic matter may favor the growth of saprophytic
organisms relative to parasitic ones and thereby reduce populations of the latter.
Biologically active compounds in soil, such as antibiotics and certain phenolic acids, may
enhance the ability of certain plants to resist attack by pathogens. [14]
* pH:
Measurements of soil pH is 4.7, this value is the most suitable for the growth of tea
plants. The soil pH has a significant effect not only on the rate but also the kind of ions
uptake. This property is also due to its effect on cellular components that are involved in
absorption, which further suggests that proteins are involved in the ion uptake. As the
31
protein structure is very sensitive to pH, its function also changes if there is any change in
the pH. That is why the maintenance of proper soil pH is very important in agriculture.
4.2 Adsorption
Results of experiments test the ability to absorb copper are shown in tables and
graphs
Table 6: Absorption of copper ions in the soil after 24 hours at lower
concentrations
Conc
0.1
0.2
0.5
1
1.25
Before
0.307
0.313
0.319
0.325
0.329
After 1 day
0.285
0.286
0.287
0.287
0.289
0.335
0.33
Adsorption
0.325
0.32
0.315
0.31
Before
0.305
After 1 day
0.3
0.295
0.29
0.285
0.28
0
0.5
1
1.5
Conc.
Fig.5: Absorption of copper ions in the soil after 24 hours at lower concentrations
32
Concentrations have decreased clearly, only small differences (ranged from 0.022
to 0.04) and increase when the concentration increases
Table7: Absorption of copper ions in the soil after 24 hours at higher concentrations
Conc
Before
After 1 day
1
1.5
0.325
0.327
0.289
0.29
2
0.337
0.291
2.5
0.347
0.295
3
0.362
0.311
0.4
0.35
Adsorption
0.3
0.25
0.2
Before
After 1 day
0.15
0.1
0.05
0
0
1
2
3
4
Conc.
Fig.6: Absorption of copper ions in the soil after 24 hours at higher concentrations
Concentrations also have decreased clearly, but the absorption value is bigger
(ranged from 0.036 to 0.052) and it also increase when the concentration increases.
33
5. DISCUSSION AND CONCLUSION
After analyzing the important factors of the soil, we can conclude that soil quality
is very beneficial for the development of tea.
Soil type is "fine clay", and it is ideal for tea. Fine clay stays sodden after raining
or sprinklers, it retains moisture. And as they dry out quicker, because of this, tea
growing in clay often deal with dry conditions better than tea in other soils. Fine clay is
usually very rich in nutrients too, which reduced need for fertilising. Howerver, one of
the disadvantages of fine clay, is that it stays wet long after rain. Because of this
disadvantage, the tea should be planted in areas where elevation and slope for easy water
drainage, avoiding submerged for tea
The pH of the soil is ideal for the growth of tea, however, it reduces the absorption
capacity of the soil. However, soil organic matter was the major determinant of strength
of Cu adsorption. This soil samples have quite high organic matter, kind of "organic soil".
Not only the major determinant of strength of Cu adsorption, it also influences the supply
of nutrients from other sources.
Although there such advantages, but the ability to absorb copper is relatively low,
absorption capacity of 7% (for the lowest concentration) to 14% (for the highest
concentration). But easy to see that, the higher the concentration, the higher absorb
ability. Since conditions of limited time, so we can not test with high concentrations.
But with the above results, we can see that the quality of the soil is very good, can
provide high-quality tea, however, because the absorption of copper is less, so the farmers
should fertilizer copper for tea regular and long-term, although only small quantities, but
34
should be maintained during the growing of tea, so tea can be achieve the best quality,
bring higher profits for farmers.
It can be predicted that the absorption capacity of the soil copper will reach high
values when testing high concentrations, however, will be limited to certain of it. I am
very interested and want to learn more about this issue, so in the future, I want to
continue this research to obtain exact results and to provide information for agriculture
and science.
35
6. REFERENCES
Vietnamese:
[1] Sở nông nghiệp & PTNT Thái Nguyên (2009) Báo cáo tình hình sản xuất
nông nghiệp tỉnh Thái Nguyên năm 2003-2004-2009.
[2] Đỗ Ngọc Quỹ, 2003, Cây chè Việt Nam sản xuất, chế biến và tiêu thụ
[3] Ngô Xuân Cường, Nguyễn Văn Tạo, (10/2004) Một số yếu tố ảnh hưởng đến
chất lượng chè xanh đặc sản. Tạp chí Nông nghiệp và Phát triển Nông thôn, tr.1334
- 1336.
[4] Hoàng Thảo Nguyên. (2014) (TTXVN/vietnam+)
[5] PGS. Đỗ Ngọc Quỹ – TS. Đỗ Thị Ngọc Oanh.(2001) Khoa học Văn hóa trà Việt
Nam và Thế Giới – Trang [211-214]
[6] Nguyễn Hữu Khải, ( 2005).Cây chè Việt Nam: Năng lực canh tranh xuất khẩu
và phát triển. Nxb Lao động Xã hội, Hà Nội,
[7] KS. Nguyễn Xuân Thự, (2012) http://nongnghiep.vn
English
[8] Rana Munns, Functional Plant Biology 36(5) 409–430)
[9] Angela Lovell, (March 22, 2012). The role of copper in plant nutrition
[10] Brian A. Schumacher, Ph.D., (April 2002). Methods for the Determination Of
Total Organic Carbon (Toc) In Soils And Sediments.
[11] Drozd J., Weber J. (red.) (1996). The role of humic substances in the ecosystem
and in environmental protection. PTSH, Wrocław.
36
[12] Das B. and Mondal N. K, (2011). Universal Journal of Environmental Research
and Technology
[13] Fred R. Davis, Kent, Ohio, (1983). Micronutrients And Plant Nutrition
[14] Fuller W.H. et al. (1956). Soil Sci. Soc. Amer. Proc. 20,218.
[15] George Rehm, Michael Schmitt, (2002). Copper for crop production, Extension
Soil Scientist,
[16] R. García and A. P. Báez, (2012). Atomic Absorption Spectrometry (AAS)
Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad
Universitaria, Mexico City,Mexico)
[17] Pravin D. Nemade, A. M. Kadam and H. S. Shankak, (2008), Department of
Chemical Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai, India
[18] Saha, P., Datta, S., and Sanyal, S. (2010). Application of Natural Clayey Soil as
Adsorbent for the Removal of Copper from Wastewater. J. Environ. Eng., 136(12), 1409–
1417
[19] Stevenson F.J. (1982). Humus chemistry. Genesis, composition, reactions.
37
APPENDICES
* The filters with 6 layers
* Measure the pH with pH meter instrument.
38
* The furnace to determine the amount of organic matter in soil
* Using AAS to determine concentration of copper element
39