1

2
EXECUTIVE SUMMARY
1. Purpose of the investigation
This report documents the findings of the investigation into the absorbent capacity of Spill-sorb with regards to Hydrochloric acid (HCl), Sulphuric acid (H
2
SO
4),
Nitric acid (HNO
3
), Acetone
(CH
3
COCH
3)
and Isopropanol (CH
3
2CHOH). The question of whether Spill-sorb also neutralizes the acids is also addressed.
2. Method of investigation
The acids and solvents were added in known quantities of Spill-sorb and the absorbent capacity and saturation level of each was determined. The pH of Spill-sorb and acid mixture was determined using an universal indicator. The neutralisation of the corrosive properties of the acid when it was added to Spill-sorb was established by testing the effect of the mix on the bare skin.
3. Results
The results show that:
3.1 The maximum absorbent capacity of Spill-sorb for HCl was one kg of peat per 5 l of acid,
3.2
i.e. a 1:5 ratio.
The maximum absorbent capacity of Spill-sorb for H
2
SO
4
was one kg of Spill-sorb per 1.4
l of acid, i.e. a 1:1.4 ratio.
3.3
3.4
The maximum absorbent capacity of Spill-sorb for HNO
3
was one kg of Spill-sorb per 3 l of acid, i.e. 1: 3 ratio.
The maximum absorbent capacity of Spill-sorb for Acetone and Isopropanol is one kg of
Spill-sorb per 5 l of solvent, i.e. a 1:5 ratio.
3.6
3.7
3.8
The Spill-sorb and acid mixtures are very acidic ( pH 0), but the corrosive properties of the mixtures are apparently negated by the Spill-sorb and acid combination.
In the presence of water/moisture the corrosive properties of the acids are restored.
A white vapour is released from the exothermic reaction between the Spill-sorb and 300 ml of HCl.
Vapour is released from the exothermic reaction between the Spill-sorb and the initial 3.9 quantity of H
2
SO
4
, s well as when the acid was added in excess.
3.10 A yellowish-brown vapour is released continuously during the exothermic reaction between Spill-sorb and HNO
3
.
3.11 No visible reaction was observed between the solvents and the Spill-sorb.
RECOMMENDATIONS
1. Use excess Spill-sorb to absorb as much of the liquid as possible and prevent spill-sorb from
2. becoming too soggy rather than according to the minimum required ratios.
Protective gear should always be used to protect against possible vapour/gas inhalation and possible contact with the skin.
1
INTRODUCTION
Following the request by Messrs. Dave Marock and Piers Bottaro for Spill-Sorb (Pty.) Ltd SA, an
AQUAimage cc Reg. No. 97/07845/23

3 investigation into the absorbency and neutralisation of Hydrochloric Acid (HCl), Sulphuric Acid (H
2
SO
4
) and Nitric Acid (HNO
3
) by Spill-sorb was undertaken between 1 - 5 March 1999. The absorbency of
Acetone (CH
3
COCH
3
) and Propanol (Isopropanol, CH
3
2CHOH) was also requested by Spill-sorb and is included in this investigation.
METHODOLOGY
-
-
-
-
The specifications of the chemicals were as follows:
-
Hydrochloric Acid (HCl) - CP- 32%. Molecular Weight 36,46; 1
Sulphuric Acid (H
2
SO
4
l
) - CP - 98%. Molecular Weight 98,08; 1
= 1,16 l = 1,84 kg kg
Nitric Acid (HNO
3
) - CP - 55%. Molecular weight 63,01. 1 l = 1,34 kg.
Acetone (CH 3 COCH
3
) - CP. Molecular weight 58,08. 1 l = kg
Isopropanol ( CH
3
2CHOH) - CP. Molecular weight 36.46. 1 l = 1.16
kg
A known quantity of Spill-sorb, 50 g , was placed in each of five round glass containers (7.5
cm deep; diameter 14 cm ). Each of the chemicals was tested individually. To each container an initial volume of 50 ml of the chemical under test was added. The volumes were progressively increased by 50 ml until the
Spill-sorb was saturated. The saturation level was taken as the point where all the fluid was absorbed but where a further increase in the volume of the chemical resulted in the fluid settling on the bottom of the container.
Universal indicator strips were used to determine the pH of the reactions after each 50 m l increase. The indicator strips were covered with the Spill-sorb-chemical mixture.
The experiments were photographed and video taped and the findings were documented.
This report deals with the results obtained and discusses issues related to the reactions of the chemicals with the Spill-sorb as well as the absorbency and possible neutralisation of the chemicals. The report concludes with recommendations with regard to the use of Spill-sorb as an absorbent for these selected chemicals.
The identification of the products formed, the gasses released or the change in structure of the Spill-sorb was not requested for this investigation and results pertaining to these aspects are therefore excluded.
2
2.
3.
4.
5.
1.
RESULTS
The results obtained from the experiments are grouped under the following headings:
1. Hydrochloric Acid and Spill-sorb
Sulphuric Acid and Spill-sorb
Nitric Acid and Spill-sorb
Acetone and Spill Sorb
Isopropanol and Spill-sorb
Hydrochloric Acid and Spill-sorb: With the addition of up to 200 ml of HCl to the 50 g Spill-sorb, no visible reaction or vapour release was observed. The acid smell was also absent. At 250 ml of acid to the 50 g of Spill-sorb (5:1 ratio), there is still no visible vapour but, a slight acidic smell is present. At this volume, Spill-sorb still absorbs the acid and Spill-sorb increased to double its original volume. The test container remained cool to the touch at this stage.
At 300 ml, Spill-sorb is unable to absorb any more HCl and the excess HCl settles at the bottom of the container. A strong acid smell is present. Visible vapour is release from the Spill-sorb and
HCl mixture. The area of the glass container in contact with the Spill-sorb and acid mixture increased in temperature.
AQUAimage cc Reg. No. 97/07845/23

4
The pH of the mixture remains highly acidic ( pH 0) throughout the experiment.
When Spill-sorb absorbs the acid, it was possible to handle the mixture even at the maximum absorbent capacity of the Spill-sorb (250 ml of HCL:50 g of peat). When an excess amount of HCl is added, the unabsorbed acid collecting at the bottom of the container is very corrosive and the mixture cannot be handled. The ability of Spill-sorb to contain the corrosive capability of the acid ceases in the presence of water/moisture and the acid regains its corrosive properties.
2. Sulphuric Acid and Spill-sorb: A chemical reaction ensued immediately on the addition of the acid to Spill-sorb. The temperature of the glass container increased and a visible vapour with a strong odour was released as a result of the chemical reaction that occurred. Spill-sorb was transformed to a paste as a result of the reaction of Spill-sorb with H
2
SO
4.
The reaction following the addition of more H
2
SO
4
to the remaining intact Spill-sorb appeared to be less violent than the initial reaction. The acid can be added to the Spill-sorb until all Spill-sorb has engaged in the reaction and is transformed to a paste. Further addition of H
2
SO
4
resulted in the acid collecting at the bottom of the container.
3
The maximum volume of acid that can be used with 50 g of Spill-sorb is 70 ml.
This amounts to a
1: 1.4 ratio of Spill Sorb to acid (i.e one kg of Spill-sorb to 1.4 l H
2
SO
4
). At 100 ml all the Spillsorb is transformed to a paste and the excess acid accumulates at the bottom of the container.
The Spill-sorb and acid mixture remains acidic ( pH 0) during the entire experiment. The Spill-sorb acid mixture appeared to have lost its corrosive properties and it was possible to handle the product with the bare hand. The capacity of Spill-sorb negate the corrosive properties of the acid is terminated in the presence of water or moisture.
3. Nitric Acid (HNO
3
) and Spill-sorb: Spill-sorb (50 g ) absorbed 50 -150 ml of the Nitric acid. Nitric
Acid reacted with the Spill-sorb immediately after the addition of even the smallest amount of
Nitric Acid, giving off a yellowish-brown vapour. The Spill-sorb turned from dark brown to yellowish-light brown. The container became progressively hotter as more acid was added. At
150 ml of acid the Spill-sorb reaches its maximum absorbent capacity for Nitric Acid. Further addition of acid resulted in the excess acid lying at the bottom of the container and is very corrosive.
The Spill-sorb and acid mixture continued releasing vapour throughout the experiment. The mixture was very acidic ( pH 0), but could be handled without burning the skin. A yellow residue was left on the skin. The addition of water to the Spill-sorb and acid mixture appeared to terminate the capacity of the Spill-sorb to negate the corrosive properties of the acid. The acid regains its corrosive properties in the presence of water or moisture which causes burning on the skin.
4. Acetone and Spill Sorb: Acetone was easily absorbed by the Spill-sorb up to 250 ml of Acetone per 50 g of Spill-sorb. With the addition of the Acetone, Spill-sorb expanded to double its size up to a volume of 100 ml of Acetone. The addition of more Acetone did not cause further expansion of the Spill-sorb and in a total volume of 250 ml of Acetone the Spill-sorb is saturated and soggy.
Further addition of Acetone (300 ml ) resulted in the unabsorbed Acetone lying at the bottom of the container.
No apparent reaction of the Acetone with Spill-sorb could be observed. The Acetone soon vaporised leaving the weight of the dry peat unchanged.
5. Isopropanol and Spill-sorb: Spill-sorb (50 g ) absorbed up to 250 ml of Isopropanol and the volume of peat increased to double its original size. Further addition of the solvent to the Spill-sorb resulted in the Spill-sorb and solvent mixture becoming drenched in solvent and the unabsorbed excess accumulating at the bottom of the container.
AQUAimage cc Reg. No. 97/07845/23

5
The container became progressively cooler as more solvent was added. No other reactions were apparent from the visual observations. The Spill-sorb and solvent mixture could be handled with no obvious effect to the skin.
DISCUSSION
1. Hydrochloric Acid (HCl) and Spill-sorb
The maximum absorbent capacity of 50 g of peat is 250 ml of HCl. This can be translated to a ratio of 1:5 of Spill-sorb to HCl , i.e. one kg of Spill-sorb can absorb 5 l of HCl. A higher ratio of acid to Spill-sorb will result in the excess acid not being absorbed. The increase in the temperature of the container and the visible vapour release at 300 ml volume indicates that an exothermic reaction has taken place.
Neutralisation of an acid is only possible if the acidic properties of the acid are removed to result in a pH of 7. Spill-sorb is unable to neutralise the acid, but appears to negate the corrosive properties of the acids. It is possible that the acid will systematically break down Spill-sorb over a period of time.
The higher the ratio of Spill-sorb to acid, the better the acid will be absorbed and the more effectively the reaction will be contained.
2. Sulphuric Acid (H
2
SO
4
) and Spill-sorb
The maximum absorbent capacity of 50 g of Spill-sorb is 70 ml of H
2
SO
4.
One kg of Spill- sorb is therefore needed for every 1.4
l of acid (1:1.4 ratio). In the reaction between Spill-sorb and
H
2
SO
4
the Spill-sorb and acid mixture is transformation into a paste as the H
2
SO
4
reacts with the
Spill-sorb in its immediate vicinity. If more Spill-sorb is added than is needed the paste will be surrounded by dry peat to form a conglomerate of paste and dry Spill-sorb.
The Spill-sorb is unable to neutralise the acid, but appears to negate the corrosive properties of the acid. The acid will systematically break down the Spill-sorb.
4
3.
The rise in temperature of the test containers indicates that the reaction that ensued is of an exothermic nature. If more acid is added than the Spill-sorb can absorb the excess acid accuumulates at the bottom of the containe.
Nitric Acid (HNO
3
) and Spill-sorb
4
AQUAimage cc Reg. No. 97/07845/23

6
The maximum absorbent capacity of Spill-sorb for Nitric Acid is 50 g of Spill-sorb per 150 ml of
HNO
3
. This translates to a ratio of 1: 3 or 1 kg of Spill-sorb per 3 l of HNO
3
. The peat is unable to absorb any more acid beyond this ratio and the excess acid will burn the skin when touched.
With Nitric Acid, the reaction with the Spill-sorb is immediate even with the addition of the smallest amount of Nitric acid so that a yellowish-brown vapour is given off continuously. The vapour is possibly toxic Nitrogen Dioxide (NO
2
) which irritates the airways and it is therefore not advisable to use the peat as an absorbent for HNO
3
without protective gear. The formation of the yellowishbrown gas is not eliminated by the addition of more Spill-sorb to the acid. 5
The Spill-sorb and HNO
3
mixture is very acidic ( pH 0) but did not appeared to be corrosive when it came into contact with the bare skin. This suggests that the corrosive properties of the acid is neutralised by the Spill-sorb and HNO
3
mixture in unsaturated form. The Spill-sorb is unable to neutralise the acid, but appears to negate the corrosive properties of the acid to such an extent that the mixture can be handled. Over a period of time the HNO
3
will possibly systematically break down the Spill-sorb. In the presence of water the acid regains its corrosive properties and causes burning to the skin.
The progressive increases in temperature of the container as more acid was added, indicates an exothermic reaction.
In the case of all three acids, the amount of Spill-sorb needed to absorb a specific acid depended on the type of acid. The Spill-sorb should therefore not become too soggy. The addition of Spill- sorb in excess of the minimum ratios will ensure that all the acid is thoroughly absorbed by the
Spill-sorb fibres.
Although the Spill-sorb and acid mixture in the case of all three acids remains acidic ( pH 0), it appears as though the initial contact with the skin does not cause major irritation. The acid is not neutralised, but the corrosive properties of the acid are in some way negated/suppressed by the
Spill-sorb. Spill-sorb appeared to be able to negate the corrosive properties of the acid. The ability of Spill-sorb to negate the corrosive properties of the acids is probably due to the physical process of absorption of the acids. The ability of the Spill-sorb to retain the corrosive properties is
depended on the volume per mass of acid to Spill-sorb. Spill-sorb added in abundance to prevent saturation with acid, will suppress the corrosive properties of the acid and it will be possible to handle the Spill-sorb and acid mixture by hand. In the case where Spill-sorb is over saturated with the acids, the Spill-sorb is no longer able to absorb any more acid.
Whether reactions occur between Spill-sorb and the acids and the exact reactions that occur between the acids and the Spill-sorb can only be determined accurately with e.g. isometric titrations. Acids are normally able to react with cellulose, also present in Spill-sorb, and form bonds with the hydroxyl molecules of the cellulose. This leads to the systematic breakdown of or change in the structure of the cellulose. The bonding of the hydrogens in the acids and the hydroxyl group on the cellulose may also help to explain why the Spill sorb cannot suppress the corrosive properties of the acids in an over saturated mixture between the acids and the Spillsorb. Saturation in this instance will mean that all the hydroxyl groups on the cellulose are involved in the reaction and over saturation will result in acids not partaking in the reaction.
There is a possibility that the interaction between the weaker acid present in Spill-sorb with the stronger HCl, H
2
SO
4
and HNO
3
causes some buffer effect, but the buffer capacity will probably be low. This is because acid in itself is not a weak enough acid to produce a very high buffer capacity with the stronger acids in question.
When water is added to the Spill-sorb and acid mixture, the acid appears to leaches out and regain its corrosive properties which cause burning to the skin.
AQUAimage cc Reg. No. 97/07845/23

7
It is not recommenced that the Spill-sorb acid mixtures be handled with the bare hands or come in contact with the skin , since any moisture on the hands or skin will cause burning to some extent. The leaching out of the acid from the Spill-sorb is a possible indication that the absorbent capacity of Spill-sorb is a physical process. Further addition of Spill-sorb to the mixture and water will result in the absorption of the liquid mixture by the Spill-sorb. The Spill-sorb and acid mixture can then once again be handled.
4 & 5. Acetone and Spill Sorb and Isopropanol and Spill-sorb .
The maximum volume of the solvents that can be absorbed by 50 g of Spill-sorb is 250 ml.
This translates to a ratio of 1:5 of Spill-sorb per solvent i.e. 1 kg of Spill-sorb per 5 l of solvent. The
Spill-sorb can be added in excess to ensure maximum solvent absorbency. The expansion of the
Spill-sorb is probably due to the absorption of the solvent by the fibres of the Spill-sorb. The Spillsorb and solvent mixture should preferably not become soggy as this indicated saturation of the peat.
The cooling down of the container with the increased volume of the solvent volume is probably due to the solvent temperature and not as a result of a reaction between the solvent and the Spillsorb.
The Spill-sorb and solvent mixture can be handled with no apparent adverse effect, but this is no grantee that the solvents are safe to handle from these short term observations. Protective gear should always be used.
RECOMMENDATIONS
1. Use peat in excess to absorb as much of the acid as possible and prevent the peat from becoming too soggy rather than according to the minimum required ratios for a particular
2. acid or solvent.
Protective gear should always be used to protect against possible vapour/gas inhalation and possible contact with the skin.
6
SUMMARY OF THE REPORT ON THE INVESTIGATION OF THE ABSORBENT AND
NEUTRALIZATION CAPACITY OF SPILL-SORB WITH REGARD TO THREE STRONG ACIDS AND
TWO SOLVENTS.
A 32% Hydrochloric Acid (HCl) was added to Spill-sorb. The spill sorb became saturated with HCl when the acid was added beyond 5:1 ratio. There was no initial reaction visible between the Spill-sorb and the acid. It was possible to handle the Spill-sorb and HCl mixture even up to saturation level. Over saturation
AQUAimage cc Reg. No. 97/07845/23

of the Spill-sorb with the acid resulted in the release of vapour and heating up of the test container.
8
Sulphuric Acid (H
2
SO
4
- 98%) was systematically added to Spill-sorb. The initial exothermic reaction between the Spill-sorb acid was more dramatic than with subsequent additions of the acid. During the initial reaction, vapour was released. The peat was transformed to a black paste. After the formation of the paste, no further vapour was visible. It was possible to handle the paste with the bare hands. Over saturation of the Spill-sorb resulted in excess acid accumulating at the bottom of the container which caused burning to the skin.
Nitric acid (HNO
3
- 55%) added to Spill-sorb resulted in an exothermic reaction taking place and a yellowish-brown vapour being released. This Nitrogen Dioxide vapour was released continuously throughout the experiment. The Spill-sorb colour changed from brown to yellowish-light brown in colour.
The Spill-sorb and acid mixture could be handled with the bare hands. Over saturation of the Spill-sorb with the acid burned the skin when it was handled.
In relation to all three acids, the Spill-sorb and acid mixture remained acidic throughout the experiment but,
Spill-sorb appeared to be able to negate or suppress the corrosive properties of the acid. The ability of
Spill-sorb to negate the corrosive properties of the acids is probably due to the physical process of abortion of the acids. The ability of the Spill-sorb to suppress the corrosive properties is depended on the volume per mass of acid to Spill-sorb. Spill-sorb added in abundance to prevent saturation with acid, will suppress the corrosive properties of the acids and it is possible to handle the Spill-sorb and acid mixture by hand. In the case where Spill-sorb is over saturated with the acids, the Spill-sorb is no longer able to absorb any more acid and the excess acid will cause burning to the skin. Further addition of Spill-sorb will absorb the acid and suppress the corrosive ability of the acid once again.
When water is added to the Spill-sorb and acid mixture, the acid leaches out and regain its corrosive properties which cause burning to the skin. Further addition of Spill-sorb to the mixture and water will result in the absorption of the liquid mixture. The Spill-sorb and acid mixture can then once again be handled.
7
Spill-sorb was able to absorb Acetone and no visible reaction was observed. The same is true for
Isopropanol. In both cases the Spill-sorb and solvent mixtures could be handled safely even when the
Spill-sorb was saturated with the solvents.
Safe results for the abortion and handling of the Spill-sorb mixed with the acids and the solvents are at a
3:1 Spill-sorb to acid or solvent addition. Protective gear should always be used to protect against possible vapour/gas inhalation and possible contact with the skin .
Vivienne C. Mabille Signature:
Credentials: M.Sc
PhD to be completed December 1999)
Ex-CSIR employer (31 October 1998)- 12 Years experience at the CSIR.
AQUAimage cc Reg. No. 97/07845/23