Adsorption of As(V) on surfactant-modified natural zeolites.
Natural mordenite (NM), natural clinoptilolite (NC), HDTMA-modified natural mordenite (SMNM) and HDTMA-modified natural clinoptilolite (SMNC) have been proposed for the removal of As(V) from aqueous solution (HDTMA=hexadecyltrimethylammonium bromide). Influence of time on arsenic sorption efficiency of different sorbents reveals that NM, NC, SMNM and SMNC require about 20, 10, 110 and 20h, respectively to reach at state of equilibrium. Pseudo-first-order model was applied to evaluate the As(V) sorption kinetics on SMNM and SMNC within the reaction time of 0.5h. The pseudo-first-order rate constants, k are 1.06 and 0.52h(-1) for 1 and 0.5g of SMNM, respectively. The observed k values 1.28 and 0.70h(-1) for 1 and 0.5g of SMNC, respectively are slightly high compared to SMNM. Surfactant surface coverage plays an important role and a significant increase in arsenate sorption capacity could be achieved as the HDTMA loading level on zeolite exceeds monolayer coverage. At a surfactant partial bilayer coverage, As(V) sorption capacity of 97.33 and 45.33mmolkg(-1) derived from Langmuir isotherm for SMNM and SMNC, respectively are significantly high compared to 17.33 and 9.33mmolkg(-1) corresponding to NM and NC. The As(V) uptake was also quantitatively evaluated using the Freundlich and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. Both SMNM and SMNC removed arsenic effectively over the initial pH range 6-10. Desorption performance of SMNM and SMNC were 66.41% and 70.04%, respectively on 0.1M NaOH regeneration solution.
Department of Materials and Life Science, Seikei University, Tokyo 180-8633, Japan.
Pratap
P
Chutia
Shigeru
S
Kato
Toshinori
T
Kojima
Shigeo
S
Satokawa
D000327:Adsorption; D001149:Arsenates / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011109:Polymethacrylic Acids; D011786:Quality Control; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000032:analysis; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
D001149:Arsenates; D011109:Polymethacrylic Acids; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C527384:hexadecyltrimethylammonium polymethacrylate; D017641:Zeolites