Application of sustainable biosorbents from hemp for remediation copper (II)-containing wastewater

Heavy-metal pollution in water is an ongoing concern throughout the world. The effective biosorption of these pollutants using sustainable hemp biomass offers an eco-friendly alternative to expensive, chemically synthesized ion exchange resin, while providing another revenue stream for hemp producers to efficiently utilize the entire crop. The biosorbents were characterized by chemical composition, FTIR, SEM, and XRD, and the results indicated that the biosorbents could be a good alternative. In addition, the biosorption of copper(II) on hemp biosorbents was investigated as the effects of initial pH of the solution, initial copper(II) concentration, dosage of hemp biosorbents in the solution, particle size of hemp biosorbents, contact time, and temperature. The biosorption of copper(II) ions was pseudo-second-order adsorption. The rate-limiting step of biosorption is intraparticle diffusion. The maximum adsorption capacity obtained from the Langmuir isotherm for copper(II) ions is 86.96 mg/g. In addition, the biosorption process is proven to be a spontaneous chemical exothermic process through adsorption isotherms and thermodynamics. This research demonstrates the feasibility of using hemp stalks as a sustainable renewable biosorbent for wastewater treatment based on lab-scale experiments.