Dye Removal from Colored Textile Wastewater Using Seeds and Biochar of Barley (Hordeum vulgare L.)

Phenol red (X-PR) and malachite green carbinol (MGC) are two textile finishing dyes, which are present in aquatic environments through industrial effluents. Due to the toxic nature of both dyes, they are harmful to human health. In the present study, two materials, barley seeds and the biochar of barley (Hordeum vulgare L.), were used to remove the dyes in an aqueous solution. The materials used are characterized by AFM, FTIR, SEM, XRD and EDX techniques. In this study, the parameters studied are the adsorbent dose, pH, initial adsorbate concentration and contact time. The maximum equilibrium time was found to be 90 min for all dyes. Kinetic studies revealed that the adsorption of X-PR and MGC on barley seeds (BS-HVL) and the biochar of barley (BC-HVL) followed pseudo-second-order kinetics and that both porous and intraparticle diffusion mechanisms were involved. The adsorption equilibrium data were well fitted to the Langmuir and Freundlich isotherm model for both materials, and the maximum adsorption capacity of monolayer and multilayers for X-PR and MGC were 71.642 mg g−1 and 50 mg g−1 on BS-HVL, and 44.843 mg g−1 and 121.95 mg g−1 on BC-HVL, respectively. The thermodynamic results reveal that the dye removal on barley was endothermic and spontaneous in nature.