Clay-biochar composite for arsenic removal from aqueous media

摘要

Arsenic is present mainly in groundwater in the forms of highly toxic arsenate and arsenite.Biochar has been a promising cost effective and carbon negative material for many different contaminants such as trace metals,antibiotics,pesticides etc.,however,not for anionic metalloids as arsenic.This study intended to evaluate the potential of a novel composite prepared using biochar,derives from fibrous fraction of municipal solid waste in Gohagoda landfill site,Kandy,Sri Lanka and red earth clay for remediate As(III) in aquecus media.Pyrolyzed biochar+red earth composite was characterized for its physicochemical properties.Furthermore,As(III) pH dependency (pH 3-9),kinetics behavior and sorbate (50-1000 μgL~(-1)) concentrations were investigated using a batch sorption technique.The concentrations of As(III) in aqueous media were measured by inductively coupled plasma optical emission spectrometry.For arsenic (III),pH 6-7 range was favorable for adsorbtion process.Whereas,highest adsorption at 24 hours reaction time at pH 6-7 recorded as around 25% (12 μgg~(-1))for arsenic (III)-Moreover,well fitted pseudo second order (R2 = 0.928) could suggest chemical adsorption mechanism rather than a physical adsorption mechanism in to the adsorbent.Hence,process involved with chemisorption can be suggested as the As(III) removal mechanism.However,further isotherm experiments are needed with expanded concentration range to mechanism identification.