Fabrication of Schiff’s base-functionalized porous carbon materials for the effective removal of toxic metals from wastewater

Abstract

The development of adsorbents for water treatment applications is an important strategy for removing hazardous materials from wastewater effluent. In this regard, an efficient adsorbent was prepared based on a combination of N′-(2-phenylacetyl) thiophene-2-carbohydrazide and low-cost porous activated carbon with 5 and 10% Schiff’s base with the aim of enhancing the efficiency of metal adsorption by the carbon. The Schiff’s base-modified carbon was characterized by SEM, EDS, XRD surface area, and FTIR. In addition, the Schiff base-modified carbon was applied for water treatment. The water samples were collected from Riyadh, Dammam, and places near industrial zones. SEM showed the porous structure of the prepared adsorbent even after modification with Schiff’s base at the two tested ratios (5% and 10%). The removal of mercury(II), lead(II), cadmium(II), and aluminum(III) from aqueous solution was evaluated. In addition, the effects of pH and contact time were investigated. Furthermore, kinetic models were applied. The optimal conditions for the removal of mercury(II), lead(II), cadmium(II), and aluminum(III) by N′-(2-phenylacetyl) thiophene-2-carbohydrazide-modified carbon were pH 6 and a contact time of 60 min. The adsorption capacities were 86.7, 70.3, 71.36, and 88.5 mg/g for mercury(II), lead(II), cadmium(II), and aluminum(III), respectively. Based on the adsorption kinetic models, the process followed a second-order kinetic model, which confirms the fast uptake of metals from the solutions. The removal efficiencies of mercury(II), lead(II), cadmium(II), and aluminum(III) from real wastewater samples were at least 90% in most of the tested real wastewater samples.