Experimental design for the optimization of copper biosorption by immobilized nanoscale lentinus edodes

Rong Chen, Fengguang Huang, Kun Zhao, Haohui Wang, Heng Xu

Key Laboratory for Bio-resources and Eco-environment of Education Ministry, College of Life Science, Sichuan University, Chengdu, Sichuan 610064, China

Abstract


An experimental design methodology was applied to study the copper removal from aqueous solutions by immobilized nanoscale Lentinus edodes. The effect of the various variables (biomass loading, initial metal ions concentration, PH, contact time, agitation speed and temperature) were studied in the batch experiment. The results showed that pH, contact time and agitation speed were the most significant variables on biosorption of copper ions determined by Minimum Run Equireplicated Res V Design. Then Central Composite Design was employed to optimize the process conditions for the maximum removal of copper. A maximum copper removal (97.57%) was found to occur under pH of 6 and contact time of 540 min and agitation speed of 125 rpm. The kinetic data agreed well with the pseudo-second-order model and the equilibrium sorption data followed the Freundlich model. Scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) analysis confirmed the apparent change of the surface morphology and the existence of copper ions on the biosorbent after metal binding. The biosorbent could be regenerated by 1M HN03 with only 8.66% decrease in adsorption capacity and the desorption of the biosorbent was of high percentage after three adsorption-desorption cycles. The present work suggests that immobilized nanoscale Lentinus edodes, an abundant low-cost biomaterial, was an efficient biosorbent for copper removal from wastewater.

Keywords


biosorption; copper; Lentinus edodes; optimization; response surface methodology

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