Abstract—This study investigated the removal of chromium hexavalent (Cr6+) using agriculture wastes. Experiments works were conducted under laboratory condition. Cr6+ was intensively used in industrial and manufacturing industries. Improper treatment of Cr6+ was lead to existing of Cr6+ in soil and groundwater. Tea waste (TW), coconut shell (CS) and orange peel (OP) were selected as an adsorbent to remove Cr6+ in this study. Characterization study on the surface morphology of TW, CS and OP was conducted using Scanning Electron Morphology (SEM), Fourier-Transfer Infrared (FTIR), and PH REdox Equilibrium (PHREEQC) software. Surface morphology of TW was significantly different compared to CS and OP. Surface morphology of TW was fully covered by wide pores and provided high reactive surface area. Surface morphology of CS and OP contained less pores compared to TW and demonstrated different type roughness. FTIR analysis revealed that TW, CS and OP contained similar chemical functional groups which were carboxyl group (C=O, C-O) and bonded-OH. Adsorption of Cr6+ on the surface of TW, CS and OP can be described by Freundlich isotherms. PHREEQC analysis demonstrated potential reaction mechanisms that may involve in this system were adsorption and complexation. Removal kinetics for Cr6+ using TW, CS and OP was measured at neutral pH under anaerobic condition using Atomic Absorption Spectroscopy (AAS). Removal of Cr6+ using TW was the highest compared to CS and OP in 30 mins (kTW >kCS >kOP). Removal kinetic rate of Cr6+ using TW, CS and OP was well fitted to pseudo-first-order kinetic. This study provides significant knowledge on the potential of TW as an economic and excellent bioadsorbent for removal of heavy metals in soil and groundwater.
Index Terms—Adsorption, agriculture waste, chromium hexavalent, removal kinetic.
The authors are with Universiti Teknologi MARA, Malaysia (e-mail: email@example.com, firstname.lastname@example.org, email@example.com).
Cite: Amnorzahira Amir, Raja Noraisar Raja Abd Rahim, and Suhaimi Abdul-Talib, "Removal of Chromium Hexavalent Using Agriculture Waste," International Journal of Environmental Science and Development vol. 8, no. 4, pp. 260-263, 2017.