Synthesis of a novel polysuccinimide based resin for the ultrahigh removal of anionic azo dyes from aqueous solution.

A novel hyper-cross-linked polyamide resin (PSI-PA) has been synthesized for the ultrahigh removal of Congo red (CR) and Eriochrom Black T (EBT) from aqueous solution. The mesoporous resin, having a specific surface area (98.80 m2 g-1), showed maximum adsorption capacity (Qmax) of 522.18 mg g-1 for CR (pH 9.0) and 460.34 mg g-1 for EBT (pH 6) at room temperature. The adsorption of these dyes was rapid and the equilibrium was attained within 4 h. The kinetic data was well-fitted by pseudo-second-order rate equation. Analysis of the surface chemical composition of loaded PSI-PA by XPS revealed the appearance of a new peak at around 166.0 eV (S 2p), confirming the adsorption of the sulfur-based dyes onto the resin. Examination of experimental data of dyes adsorption by a variety of non-linear adsorption isotherms and kinetic models suggested that the Langmuir model exhibited the best fit with high correlation coefficients for both CR (R2 = 0.9966) and EBT (R2 = 0.9934). PSI-PA has been extensively characterized by FT-IR, solid state 13C (CP-MAS) NMR, EDS, TGA and BET analysis. Moreover, PSI-PA exhibited 82% removal efficiency for dyes in simulated effluents, manifesting its promise and utility for treating industrial effluent.

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.