Removal of Pb2+ onto HDTMA-Br Modified Kaolinite Clay as function of pH: Batch Sorption, Isotherms and Kinetics

Abstract

Adsorption removal of toxic heavy metals from wastewaters is considered as one of the most important methods of wastewater treatment due to its low maintenance cost, high efficiency and ease of operation. The adsorption capacities of some specific clay minerals have been known to improve significantly when modified with quaternary ammonium compounds (QACs).In the present study, kaolinite clay from Alkaleri LGA, Northeast-Nigeria was characterized and modified with a cationic surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br) and applied for batch sorption of Lead (II) ion contaminant from aqueous solution at different pH values. The results showed that Lead (II) ion uptake decreased with increase in pH. The maximum Pb 2+ removal efficiency was 99.68% at pH3 and least at pH11 with 87.10%.The Langmuir adsorption isotherm proved to be the best fit based on correlation factor R 2 ranging from 0.9630-0.9950, while pseudo-second order kinetic was found to be the best fit based on R 2 ranging from 0.9860-0.9960.The negative values of Temkin binding energy (bT) indicated that the process was exothermic. The high values of free energy E (1.8227×10 1 -1.0000×10 3 kJ/mol) from Dubinin-Radushkevich (D-R) isotherm