Arsenic removal from water using lignocellulose adsorption medium (LAM).
Arsenate in water is readily adsorbed on lignocellulose adsorption medium (LAM) which is cotton-based and has been coated with iron(III) by soaking cotton pellets in ferric chloride solution. Capacities achieved with LAM average 32.8 mg As/g of medium at influent arsenic concentrations ranging from 20-30 mg As/L. Adsorption follows (R2 = 0.993) a Freundlich isotherm, (x/M) = 22.845 Ce0.25, where (x/M) is the ratio of milligrams of contaminant adsorbed per gram of adsorbent and Ce is the equilibrium concentration. As is often the case with adsorption from solution, the fit using a Langmuir isotherm was not as good (R2 = 0.8786). The adsorbent when saturated can be regenerated by treatment with dilute sodium hydroxide. After five regenerations, the capacity dropped by 11.5%. Arsenate washed off the adsorbent after regeneration, as well as that left on the medium, may be concentrated and disposed of properly or perhaps recycled. Consideration of costs shows that one ton of iron(III)-treated adsorbent can be used to remove arsenate at toxic levels from drinking water at a cost of about 3.20/ton US dollars plus the cost of media without regeneration.
Kim
Juyoung
J
H2O Technology, LLC, Valdosta, Georgia, USA.
Mann
Justin D
JD
Spencer
Jesse G
JG
D000327:Adsorption; D001149:Arsenates / Q000032:analysis*; D002482:Cellulose / Q000737:chemistry*; D002712:Chlorides; D005290:Ferric Compounds / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000191:economics / Q000295:instrumentation / Q000379:methods*
D001149:Arsenates; D002712:Chlorides; D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; C036909:lignocellulose; D002482:Cellulose; D008031:Lignin; C025657:arsenic acid; C024555:ferric chloride