Study on Production of Biochar from Biomass and its Application as a Low-Cost Adsorbent
Loading...
Date
2019
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
MPUT, UDAIPUR
Abstract
Biochar exhibits a great perspective to efficiently tackle heavy metals
considering the wide availability of raw material, low-cost and physical and chemical
surface characteristics. The present investigation was focused on the production of the
biochar from biomass and evaluates its application as a low-cost adsorbent for the
removal of heavy metals from wastewater. The biochars were prepared from three
feedstocks (groundnut shell, chickpea straw, and wheat straw) through slow pyrolysis
inside a fixed-bed type fast pyrolysis system at 500, 550, and 600⁰C by keeping same
residence time of 1 h. Biochar yields of groundnut shell, chickpea straw, and wheat
straw at 500, 550, and 600⁰C were estimated about 35.7, 31.08, and 28.57% for GSB;
33.14, 31.5, and 27% for CSB and 37.71, 36.28, and 35.25% for WSB respectively.
Ultimate analysis of GSB, CSB and WSB 600⁰C found that it contains a
higher percentage (75.29, 68.30 and 53.64) of carbon whereas hydrogen and nitrogen
content was lower. SEM analysis of feedstock material and GSB, CSB, and WSB at
500, 550, and 600⁰C shows the availability of a large number of pores with uniform
size distribution compared to original feedstock materials. The FTIR spectra of
biomasses and its biochar sample shows availability of various functional group such
as amino, amines, hydroxyl, alkyl, carboxylic, ester, etc. The moisture adsorption and
desorption study indicated that the WSB at 600⁰C is more efficient than silica gel. The
adsorption capacity of moisture on the WSB is relatively higher (30%) than that of
silica gel (28%). Further, the percentage of moisture loss was 32 and 34% in silica gel
and biochar respectively.
Among all biochar formed at 600⁰C, WSB demonstrated 99 and 78% removal
of Pb and Zn respectively. Using multiple responses optimization technique for Pb
and Zn removal a set of process variables i.e. biochar dose, heavy metal concentration
and contact time were found out to be 2.90 (gm), 22 (ppm) and 309 (min)
respectively. Corresponding to these values of process variables, the values of
percentage removal Pb and Zn were 99.20 and 97.16% respectively. Satisfactoriness
of proposed second order models built-up for Pb and Zn removal through regression
analysis was confirmed by R2. The R2 values were found to be 0.998 and 0.999 for Pb
and Zn respectively, showing a good fit of the model to data. The results of ANOVA
revealed that all the variables had significant effect on the removal of Pb and Zn
Description
Study on Production of Biochar from Biomass and its Application as a Low-Cost Adsorbent
Keywords
Citation
Vaghela D.R. and Sharma D.