Synthesis of a novel 3,5-diacrylamidobenzoic acid based hyper-cross-linked resin for the efficient adsorption of Congo Red and Rhodamine B.

A novel hyper cross-linked, 3,5-diacrylamidobenzoic acid based resin (APEADA) has been synthesized for the highly efficient removal of Congo red (CR) and Rhodamine B (RhB) from aqueous solution. The synthesized resin was extensively characterized by FT-IR, FESEM, PXRD, EDX, BET analysis, TGA and solid state 13C (CP-MAS) NMR. APEADA exhibits thermal stability (≈ 200 °C) and a considerable surface area (64.78 m2 g-1), as suggested by Thermogravimetric Analysis (TGA) and Brunauer-Emmett-Teller (BET) analysis, respectively. The experimental data of dyes adsorption onto resin was examined by a variety of isotherm models wherein Langmuir and Temkin models were found to be the best fit for explaining the adsorption of both RhB (R2 = 0.9899) and CR (R2 = 0.9919). The resin can efficiently remove CR (92.03%) at pH 8.14 and moderately adsorb RhB (45.3%) at pH 5.01 and exhibits maximum adsorption capacity (Qmax) for CR (280.0 mg g-1) and RhB (23.28 mg g-1) at 318.6 K. The thermodynamic analysis of the data revealed that the adsorption processes were exothermic and spontaneous. Moreover, APEADA showed efficient removal efficiency (80.13%) for dyes in simulated effluents which warrants its utility and effectiveness in industrial waste water treatment.