ZINC OXIDE XEROGEL DESULFURIZATION SORBENT:
SYNTHESIS AND PROPERTIES
Kannasoot Kannokkanchana1,*, Sumittra Charojrochkul2, Waret Veerasai1,#
1
Physical Chemistry Program, Department of Chemistry, Faculty of Science,
Mahidol University, Bangkok 10400, Thailand
2
National Metal and Materials Technology Center, Pathumthani 12120, Thailand
*e-mail: kannasoot.bas@gmail.com, #e-mail: waret.vee@mahidol.ac.th
Abstract
This research aims to synthesize zinc oxide xerogel desulfurization sorbent for biogas by
using simple zinc nitrate salt and simple process called epoxide addition method. In the
preparation step, zinc nitrate precursor solution was simply mixed with propylene oxide
gelation initiator. Effect of precursor solution concentration and amount of gelation initiator
was also studied. After the gelation process was completed, xerogel was washed by acetone
and dried under atmospheric condition. As-prepared xerogel was investigated by powder Xray diffractometer (PXRD), scanning electron microscope (SEM), and thermogravimetric
analysis (TGA) to obtain phase, morphology and appropriate calcination temperature. After
characterization, the as prepared sorbent was calcined at 250°C to obtain zinc oxide xerogel
sorbent. The sorbent was characterized again by PXRD, SEM, and Brunauer-Emmett-Teller
nitrogen adsorption (BET) to confirm phase, morphology and surface area. Then, a
desulfurization performance of the sorbent was measured by using a glass reactor coupled
with micro GC. The removal efficiency of as-prepared zinc oxide xerogel sorbents are greater
than 99.98% resulting in the outlet H2S concentration <2ppmv from 10050 ppmv inlet gas,
which passed Department of Energy Business standard for NGV (H2S<23 ppmv). The
desulfurization capacities of as-prepared sorbents in the range of 6.67 – 9.43 mgS/g are
achieved at 30°C.
Acknowledgements: This research was supported by Thailand Graduate Institute of Science
and Technology Scholarship (TGIST) under the grant No.TG-33-14-54-041M from National
Science and Technology Development Agency (NSTDA), National Metal and Materials
Technology Center (MTEC), and Faculty of Science, Mahidol University.
Keywords: zinc oxide, desulfurization, xerogel, biogas