Application of response surface methodology for optimization of dissolved solids adsorption by activated coal

The adsorptive removal of total dissolved solids by activated coal using response surface methodology was investigated. A four-variable central composite experimental design was applied to correlate the adsorption variables (effluent pH, adsorbent dosage, contact time, and adsorption temperature). The adsorption variables were optimized based on the removal of total dissolved solids from fibre cement industry effluent. Three-dimensional surface plots were generated to estimate the effect of the combinations of the independent variables on the adsorption efficiency. The results of the model validation gave experimental yield 96.2%, predicted yield 96.5% obtained at effluent pH 6.27, adsorbent dosage 27.60 mg L−1, contact time 48.00 min, and adsorption temperature of 31.00 °C. The good agreement found between observed and predicted values supports the suitability of the applied model to predict the adsorption treatment.