Nanocomposite magnetic hydrogel based on κ-carrageenan and acrylic acid for the removal of Cd(II), Co(II), Cu(II), and Ni(II); Efficient adsorption enhanced by activated carbon and magnetic nanoparticles.

A novel nanocomposite magnetic hydrogel was synthesized based on κ-carrageenan, acrylic acid, and activated carbon as an absorbent for removing heavy metal ions from aqueous solution. FT-IR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibration sample magnetometer (VSM) were employed to confirm the structure of the nanocomposite hydrogels. The effects of contact time, pH, particle size, temperature, and metal ion concentration on the metal ion adsorption were investigated.

Alkaline range pH sensor based on chitosan hydrogel: A novel approach to pH sensing.

Monitoring of pH under extreme alkaline range is still a challenge due to the lack of accuracy and validity. This research developed a novel pH sensor (hydrogel/BTB) based on the transition of bromothymol blue from the hydrogel matrix into the pH-examining sample solution. The hydrogel/BTB sensor was synthesized through the solvent casting of chitosan, citric acid as the crosslinker, and bromothymol blue as a pH-sensitive dye.

Copper(II) containing chitosan hydrogel as a heterogeneous Fenton-like catalyst for production of hydroxyl radical: A quantitative study.

The Fenton reaction, which generate hydroxl radical as a powerful oxidizing agent, is of interest due to its role in biological systems and wastewater treatment. However, unlike the ferrous/ferric system that is active only in acidic condition, the copper ion can operate over a wide pH range as a Fenton-like system. In this research a copper containing hydrogel (Cu/CH) was prepared by loading the Cu ions into a hydrogel based on chitosan, acrylamide (AAM), and acrylic acid (AA), and used for production of hydroxyl radical in a Fenton-like reaction.

Nanocomposite hydrogel based on sodium alginate, poly (acrylic acid), and tetraamminecopper (II) sulfate as an efficient dye adsorbent.

In this study, a novel nanocomposite hydrogel (NCH) was prepared by in situ crosslinking and radical polymerization of acrylic acid (AA) in the presence of sodium alginate (Na-Alg), followed by loading of Cu ions and reaction with ammonia. The main advantage of the synthesized NCH is the high adsorption of dye due to the large contact area. The structure of the NCH was studied by FT-IR spectroscopy, TEM, and SEM.