Lignocellulosic Juglans regia waste-derived magnetically separable nanocomposite for enhanced malachite green dye...

A novel magnetized Juglans regia shell (MJRS) nanocomposite was synthesized via an in-situ co-precipitation method and utilized to effectively remove malachite green (MG) dye from an aqueous solution. Various conventional and modern analytical methods were used to characterize the adsorbent, including SEM/EDS, XRD, VSM, TGA, FTIR, BET, and the point of zero charge. The effects of various experimental parameters, such as pH, dose, contact time, initial dye concentrations, and temperature, on MG removal were explored through batch experiments using the MJRS nanocomposite. Kinetic data followed the pseudo-second-order model, and adsorption equilibrium aligned with the Langmuir model. The maximum monolayer adsorption capacity increased with temperature, reaching 251.889 mg/g at 298 K, 318.471 mg/g at 308 K, 381.679 mg/g at 318 K, and 440.529 mg/g at 328 K. The temperature-dependent study illustrated that the adsorption process was thermodynamically favorable, endothermic, and spontaneity increases with temperature. MJRS nanocomposite was successfully and effectively utilized for up to seven hydrochloric acid regeneration cycles, with a minimum significant decline in adsorptive performance observed. As a result of their ease of isolation from treated effluent, the synthesized MJRS nanocomposite was considered an efficient, easily separable, and excellent reusable adsorbent for removing MG dye.