Synthesis and Application of Modified Orchard Waste Biochar for Efficient Scavenging of Copper from Aqueous Solutions

Efficient adsorbents were fabricated by modifying the orchard waste biochar (BC) to produce zero-valent iron composited BC (BC/Fe⁰) and phosphorus embedded BC (BC/P). The efficacy of these adsorbents for copper [Cu(II)] removal from aqueous media was investigated via pH, kinetics, and adsorption batch trials. The solution pH 7 was found optimum for the highest Cu(II) removal. Elovich model was fitted well to the Cu(II) kinetics adsorption and higher initial sorption rate 79.44, 75.71, 72.28, 61.60 mg g⁻¹ min⁻¹ for BC/Fe⁰, BC, AC, and BC/P, respectively, was observed than other kinetic models. Langmuir, Freundlich, and Redlich–Peterson isotherm models were applied to the experimental data and Langmuir model fitted well predicting the adsorption capacity of 427.11 mg g⁻¹. The BC became more selective in copper removal after the introduction of Fe⁰, and a higher removal rate of Cu(II) was observed in a short time compared to the other tested adsorbents. Therefore, zero-valent iron composited orchard waste-derived biochar as a green and cost-effective adsorbent can open new ways for the efficient removal of Cu(II) from aqueous solutions.