Adsorption of lead, copper and zinc in a multi-metal aqueous solution bywaste rubber tires for the design of single batch adsorber

Abstract

Heavy metal pollution has emerged as one of the most serious environmental challenges facing the world today.The removal of heavy metals from the effluent is of special environmental concern because of their toxicity andpersistence in nature. This study presents the suitability of activated carbon from waste rubber tire as a low-costadsorbent for multiple adsorption of copper, lead and zinc from wastewater. The adsorbent removed heavy metalions effectively from solution medium in the order of copper>lead>Zinc. The adsorption process was rapid withall metals reaching equilibrium within 120 min. The optimum pH for Lead was achieved at 5 and 6 for copper andZinc. The removal of heavy metals was discovered to increase with adsorbent dosage and contact time andreduced with initial concentration. The adsorption of multiple heavy metals was modeled using Freundlich andLangmuir adsorption isotherms to assess the experimentalfindings. The equilibrium data betterfitted to theLangmuir isotherm with regression coefficient (R2) of 0.9831, 0.9992 and 0.9953 for lead, copper and zincrespectively. The maximum adsorption capacities (Qmax) at equilibrium were 9.6805 mg/g, 12.4378 mg/g and4.9950 mg/g for Lead, Copper and Zinc respectively. The adsorption kinetics indicated that pseudo-second-orderkinetic model described well the sorption mechanism for multiple adsorption of heavy metals with R2of morethan 0.99 for all metal ions. An empirical model for predicting and designing of a single batch adsorber for 95 %multiple heavy metal ion removal at any given initial heavy metal ion concentration and effluent volume wasfurther developed using activated carbon from waste rubber tires. Waste rubber tire Activated carbon demon-strated an ability for the treatment of wastewater containing these heavy metals in multimetal solutions.