Adsorption of Reactive Blue Dye onto Natural and Modified Wheat Straw

摘要

Conventional treatment of textile wastewater such as biological treatment discharges will no longer be tolerated and identified as non-biodegradable. Advanced processes such as adsorption and advanced oxidation hold great promise to provide alternative for better treatment and protection of environment. In this study, adsorption process is carried out for both batch (kinetic and isotherm) studies using natural wheat straw (NWS) as low cost adsorbent, modified wheat straw (MWS) and Activated Carbon (AC) for comparing the results. Batch adsorption experiments were conducted on a shaker at 200 rpm, room temperature using 250 mL conical flasks contains 100 mL of dye solution to study the effects of adsorption conditions. The effect of pH was determined by adjusting pH values (2.5- 10.5). To study the effect of initial dye concentration, six different concentrations of reactive blue dye (5, 20, 30, 50, 70 and 90) mg/L were prepared and used. Results showed that the removal percent using NWS, MWS and AC are; 68%, 92.17% and 90.5% respectively. Equilibrium isotherm experiment were carried at different dosages (0.1 – 1 g) to predict the isotherm model; Langmuir, Freundlich and BET. The experimental data showed that reactive blue is fitted with Freundlich isotherm (1=1.25, 0.67) for both (NWS) and (MWS) respectively, and for (AC) is fitted with Langmuir isotherm. Three kinetic models, were selected to fit the kinetic data; pseudo first, second order and intraparticle diffusion, reactive blue is fitted with intra-particle diffusion model with (NWS) and (MWS), and Pseudo second order for (AC).