Adsorption behavior of cadmium ions onto phosphoric acid-impregnated microwave-induced mesoporous activated carbon

• Main Authors: Tan, I. A. W., Chan, J.C., Hameed, Bassim Hamid, Lim, Leonard Lik Pueh
• Format: E-Article
• Language: English
• Published: Elsevier Ltd 2016
• Subjects: TP Chemical technology
• Online Access: http://ir.unimas.my/id/eprint/15279/1/Adsorption-behavior-of-cadmium-ions-onto-phosphoric-acid-impregnated-microwave-induced-mesoporous-activated-carbon_2016_Journal-of-Water-Process-Engineering.html; http://ir.unimas.my/id/eprint/15279/; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85002579191&doi=10.1016%2fj.jwpe.2016.10.007&partnerID=40&md5=dad015b32cd66df7cfe356b8038e107c

This study investigated the potential of mesoporous activated carbon derived from oil palm shell using phosphoric acid (H3PO4) impregnation followed by microwave-induced irradiation, for adsorption of cadmium from aqueous solution. This study investigated the effects of H3PO4 impregnation ratio (1:1, 1:2 and 1:3 w/w) and microwave irradiation time (5 and 8 min) on the characteristics of the synthesized activated carbon, encompassing the textural, morphological, proximate and chemical properties. Batch adsorption studies were conducted for the activated carbon to determine the effects of contact time, initial cadmium concentration (20–200 mg/L) and solution pH (2–10) on the cadmium ions uptake at 30 °C. The synthesis process resulted in the development of pores, with average diameter of 2.22 nm, on the surface of the oil palm shell, which contributed to the relatively large BET surface area and total pore volume of 854.42 m2/g and 0.74 cm3/g, respectively. Batch adsorption studies showed that the adsorption of cadmium increased with increasing concentration and was more favourable at acidic pH, achieving up to 99% removal. The adsorption of cadmium on the activated carbon was of chemisorption and governed by external mass transport. The maximum monolayer adsorption capacity of 227.27 mg/g showed the potential of the proposed synthesis method for deriving mesoporous oil palm shell-based activated carbon for removing cadmium from aqueous solutions. The saving in terms of the reduction of activation time and energy usage shall make the production of activated carbon from agricultural biomass to be more environmental friendly and sustainable for wastewater treatment