Sulfonated modification of cotton linter and its application as adsorbent for high-efficiency removal of lead(II) in effluent

Sulfonated modification of cotton linter and its novel application as adsorbent for Pb2+ in effluent were investigated. Results show that sulfonated cotton linter (SCL) has strong adsorbability for Pb2+, more than 85% of Pb2+ can be removed at lower Pb2+ concentration (<20 mg/L). Its adsorbability for Pb2+ is related to effluent pH, temperature, and initial Pb2+ concentration. The adsorption process can reach equilibrium within 8 min, which can be described through the pseudo-second-order kinetic model. The adsorption isotherm is closely fitted with the Temkin isotherm model, which suggests that the adsorption of Pb2+ on SCL can be regarded as chemical adsorption. The adsorption process of Pb2+ on SCL is non-spontaneous and endothermic, based on the value of Gibbs free energy and enthalpy. Compared with commercial activated carbon, SCL is simple to prepare and does not require any special technology.