Removal of Cu²⁺ and SO₄ ^2- from aqueous solutions on surface functionalized dehydrated carbon from date palm leaflets

Dehydrated carbon (DC) was prepared from date palm leaflets via sulfuric acid dehydration at 200°C. DC surface was functionalized using ethylene diamine via amide coupling to produce basic dehydrated carbon (BDC). DC possesses high content of carboxylic groups acting as cation exchanger, however, BDC possesses amine and amide groups that are capable of chelating Cu²⁺. However, when protonated, the amine group acts as anion exchanger for SO₄ ^2-. ∼81% of the carboxylic groups on DC were successfully functionalized to amide-amine groups on BDC surface. Sorption of Cu²⁺ and SO₄ ^2- was investigated at different initial pH, contact time and ion concentration. Initial pH values for maximum sorption were found to be 5 and 2 for Cu²⁺ and SO₄ ^2- _, respectively, and were used in the kinetic and equilibrium studies. Sorption kinetics data follow well pseudo second order kinetic model. Equilibrium sorption data follow well the Langmuir isotherm. BDC in general shows better performance for Cu²⁺ and SO₄ ^2- removal than DC. Both carbons show capability of combined equal mass removal of both Cu²⁺ and SO₄ ^2- at initial pH 2.8 and 3.5 for DC and BDC, respectively, with good recycle properties for 4 cycles in this study.