Removal of Cr(VI) from wastewater using activated tamarind seeds as an adsorbent

Abstract

In the present study, an adsorbent was prepared from tamarind seeds and batch studies were conducted for Cr(VI) removal from aqueous solutions. Tamarind seeds were activated by heat treatment and with concentrated sulfuric acid (98% w/w). The parameters investigated include initial pH, contact time, initial Cr(VI) concentration, and adsorbent dosage. The adsorption of Cr(VI) was found to be maximum at low values of initial pH in the range of 1–3. The adsorption process of Cr(VI) was tested with Langmuir and Freundlich isotherm models. Application of the Langmuir isotherm to the systems yielded maximum adsorption capacity of 29.08 mg g–1. The adsorption process followed second order kinetics and the corresponding rate constant was found to be 0.0026 g mg–1 min–1.