Synthesis and characterization of super dye adsorbent hydrogels based on acrylic acid and acryloyl tetrasodium thiacalix[4]arene tetrasulfonate

Abstract

Acryloyl tetrasodium thiacalix[4]arene tetrasulfonate (ACSTCA) was synthesized via fictionalization of tetrasodium thiacalix[4]arene tetrasulfonate (STCA). Hydrogels based on acrylic acid (AA) (20-70 mol%) and ACSTCA (30-80 mol%) were prepared by solution copolymerization in water using methylene bisacrylamide and ammonium persulfate as crosslinker and initiator, respectively. The gels obtained exhibited a good ability for absorbing water. Swelling of the gels was improved with increase in ACSTCA content in the gel feed. Characterization of the synthesized monomer (ACSTCA) was performed using mass spectrometry and Fourier transform infrared (FTIR), 1 H and 13 C NMR spectroscopies and the synthesized gels were characterized by FTIR. The thermal and mechanical properties of these copolymers were also studied using TGA and dynamic mechanical thermal analysis. The glass transition temperature and storage modulus of the copolymer were increased with increasing content of ACSTCA in the gel. Thermal stability was improved with increasing ACSTCA content in the structure of the copolymer. The results showed that the synthesized copolymer (ACSTCA-AA) can effectively remove dye from wastewater. The dye removal capacity of the gels was investigated with a UV−visible spectrophotometer. In addition, the effect of key operation parameters such as the ACSTCA content in the structure of the copolymer, contact time, adsorbent dosage, pH of the solution and temperature on dye removal from aqueous solution was experimentally studied. The equilibrium data were analyzed using the Langmuir and Freundlich adsorption isotherms. The Freundlich isotherms provided a better fit to the data. Results from the kinetic studies revealed that the adsorption of malachite green onto the hydrogels followed a pseudo-second-order kinetic model.

Nanopore-Based Strategy for Sequential Separation of Heavy-Metal Ions in Water

“…The purpose of converting TCA into TCAS was to introduce sulfonic groups to TCA molecular structure and make it water-soluble. 2 g of TCA and 80 mL of concentrated sulfuric acid were poured into a 100 mL beaker, and the temperature was controlled at 80 °C for 4 h. − The final extracted substance was TCAS with high purity.…”