SORPTIVE REMOVAL OF CHLORIDE AND SULPHATE IONS IN WASTEWATER FROM AN ADVANCED CHEMISTRY LABORATORY
Authors
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Utange, P. I.
Centre for Food Research and Technology, Rev Fr Moses Orshio Adasu University (Formerly Benue State University), Makurdi – Nigeria
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Wuana, R. A.
Department of Chemistry, Joseph Sarwuan Tarka University, Makurdi – Nigeria
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Eneji, I. S.
Department of Chemistry, Joseph Sarwuan Tarka University, Makurdi – Nigeria
Abstract
The removal of chloride and sulphate ions in wastewater from an advanced chemistry multipurpose laboratory was conducted using activated carbon adsorbents from seed shells of Irvingia gabonensis (CIG150 = 150 µm and CIG300 = 300 µm particle size) and a commercial activated carbon (CAC). Chloride and sulphate ions were quantified using turbidimetric method. Adsorption experiments were conducted in batch mode considering the effect of pH, adsorbent dosage, contact time and isotherms. The optimum adsorption capacity for the adsorption of chloride ions onto CIG150 and CIG300 were 4.973 and 5.392 mg/g at pH 6.8 respectively while CAC recorded 3.147 mg/g at pH 7.6; CIG300 and CAC recorded 2.892 and 3.145 mg/g for the adsorption of sulphate at pH 7.7 while the sulphate-CIG150 adsorption system recorded optimum adsorption capacity of 2.526 mg/g at pH 8.1. Langmuir isotherm fitted the equilibrium data for the adsorption studies. Chloride ions recorded Langmuir maximum adsorption capacity, (mg/g) for CIG150, CIG300 and CAC as 2.6998, 2.8637, 2.8794 at 298 K; 2.7824, 2.9718, 2.9745 at 303 K and 2.8802, 3.0572, 3.1133 at 308 K respectively. Similarly, sulphate ions recorded (mg/g) as 1.3738, 1.3144, 1.4835 at 298 K; 1.4223, 1.4118, 1.5456 at 303 K; 1.4923, 1.5158, 1.6345 at 308 K. The calculated thermodynamic quantities indicate that, the adsorption process for the uptake of chloride and sulphate ions were spontaneous, exothermic and characteristic of physical adsorption. The Weber-Morris intra-particle kinetic model explained the adsorption process. Activated carbon from Irvingia gabonensis seed shells was thus recommended for real wastewater treatment.
Keywords: Sorptive Removal, Chloride, Sulphate, Wastewater, Irvingia Gabonensis, Adsorption Isotherms, Kinetic Models, Thermodynamics