Competitive and cooperative adsorption analysis for dye removal from multicomponent system using Prosopis juliflora activated carbon.

In this study, performance evaluation of two adsorbents synthesized using invasive weed, i.e., Prosopis juliflora, was chemically activated using hydrochloric acid (HPJ) and sodium hydroxide (NPJ). The synthesized adsorbents HPJ and NPJ were subjected to SEM, EDX, XRD, FTIR, and porosimetry analysis for characterization and applied for adsorptive removal of rhodamine B (RB) and methyl orange (MO) dyes from monocomponent (MO/RB) and multicomponent (MO + RB) systems in batch mode. Meanwhile, the effect of operational parameters such as contact time, HPJ and NPJ dosage, MO/RB concentration, and [Formula: see text] on sorption of MO/RB dyes was investigated. The adsorption data was modeled through various kinetic and equilibrium models. On the other hand, the multi-dye sorption system was modeled using Langmuir competitive isotherm. Furthermore, the effect of presence of one dye on sorption of other and vice versa, i.e., competitive (antagonistic) and cooperative (synergistic) nature of sorption process, was investigated. From the results, it was observed that pseudo-second-order kinetic and Langmuir isotherm models best fit the adsorption kinetic and equilibrium data for sorption of MO and RB dyes using both HPJ and NPJ as adsorbents. Langmuir's maximum sorption ability (q m ) of HPJ for sorption of MO and RB dyes was observed to be 12.77 mg/g and 9.95 mg/g, respectively, from the monocomponent system. On the other hand, q m of NPJ for sorption of MO and RB dyes was observed to be 10.51 mg/g and 8.69 mg/g, respectively. Langmuir's sorption ability (q m ) was slightly higher in the MO + RB mixture in contrast to MO/RB. As a result, the sorption of MO/RB dyes from the MO + RB system showed synergistic nature. In conclusion, the HPJ and NPJ could be effectively used as sorbents for sorption of dyes from effluents.