Effects of pH and concentration on the capability of E. coli and S. epidermidis with bentonite clay as biosorbent for the removal of Copper, Nickel and Lead from polluted water

¹ Environmental Engineering Graduate Program, Mapua University, 658 Muralla St., Intramuros, Manila, Philippines 1002
² Office of International Linkages for Research and Development, 2/F Research Building, Mapua University, 658 Muralla St., Intramuros, Manila Philippines 1002
³ Department of Natural Resources Management, College of Sustainable Environment, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
⁴ Biological Engineering Program, Mapua University, 658 Muralla St., Intramuros, Manila, Philippines 1002
⁵ School of Microelectronic Engineering, University Malaysia Perlis (UniMAP), Kampus Alam, Pauh Putra, 02600 Arau, Perlis, Malaysia.

^* Corresponding author: dbsenoro@mapua.edu.ph

Published online: 22 November 2017

Abstract

This paper discusses the effects of pH and concentration on the capability of E. coli ATCC29522 and S. epidermidis RP62A biofilm with bentonite in removing divalent copper, nickel and lead from wastewater. Batch adsorption study at laboratory scale was utilized to evaluate the potential use of bacterial biomass (E. coli ATCC29522 and S. epidermidis RP62A) aided with geosynthetic clay (bentonite) for the removal of Cu²⁺, Ni²⁺and Pb²⁺. Results revealed that removal of Cu²⁺, Ni²⁺and Pb²⁺ by both types of organisms supported with bentonite were high in the first 4 hours of the experiment. This illustrates that the binding site on that particular time was abundant. Hence, the removal rate was evident at high concentration depicting the line adsorption equilibrium. It also revealed that S. epidermidis RP62A supported with bentonite had the highest affinity to Copper and Lead with Qm = 277.7 mg/g and 5.0075 mg/g, respectively. While E. coli ATCC 29522 had the highest affinity to Nickel (Qm= 58.82 mg/g). Hence, the sorption of Cu²⁺, Ni²⁺and Pb²⁺ onto E. coli ATCC29522 and S. epidermidis RP62A biofilm supported with bentonite clay occurred through monolayer chemisorption on the homogeneous surface of E. coli ATCC29522 and S. epidermidis RP62A biofilm with bentonite clay. Batch kinetics studies revealed that the sorption of Cu²⁺, Ni²⁺and Pb²⁺ onto E. coli ATCC29522 and S. epidermidis RP62A biofilm supported with bentonite clay was well described by a pseudo-second-order equation model of type 1 (R2 = 0.9999), which implies that chemisorption is the rate limiting step.