3D printed cylindrical capsules as a Chlorella pyrenoidosa immobilization device for removal of lead ions contamination

Immobilization is considered as a promising strategy toward the practical applications of powdered adsorbent. Herein, three dimensional (3D) printing cylindrical capsules with cross-linked PVA hydrogels membrane in encapsulate Chlorella pyrenoidosa (Cp) were utilized for removal of lead ions. The chemical compositions, hydrogels performance and morphologies of the membranes were determined by Fourier transformed infrared spectroscopy (FTIR), cross-linking degree, swelling degree, membrane flux and scanning electron microscopy (SEM). It is found that PVA cross-linking structure is successfully synthesized on the surface of capsule body and cap due to the presence of PVA in the filament. The lead ions adsorption capacity related to initial concentration of 50 mg/L in 48 h is reached 75.61%, revealing a good removal ability. The self-floating 3D printed capsules device also shows an excellent recovering property. After 7 runs of adsorption experiment, the lead ions adsorption ratio remains 78.56%, which will bring a broad prospect in wastewater treatment, chemical slow release along with sample preparation and separation.

Polymeric nanocomposites for the removal of Acid red 52 dye from aqueous solutions: Synthesis, characterization, kinetic and isotherm studies

Polymeric nanocomposites polyaniline-polyvinylpyrrolidone (PAPV) and polyaniline-polyvinylpyrrolidone-neodymium/zinc oxide (PAPV-NZO) were synthesized for the effective dye removal through adsorption process. Neodymium doped zinc oxide (NZO) with various proportions of neodymium were prepared by chemical co-precipitation method and incorporated into the copolymer matrix via oxidative polymerization technique. NZO nanoparticles were characterized by X-ray diffraction (XRD) and the morphological features, and functional group linkages of the PAPV-NZO were confirmed by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) analyses. Acid red 52 dye was chosen as a synthetic toxic effluent to study the removal efficiency of the nanocomposites with different parameters viz. time, concentration, adsorbent dosage and pH. The studies were performed under visible light irradiation and the residual dye concentration was analyzed by UV-visible spectrophotometer. PAPV-NZO exhibited greater dye removal rate than PAPV due to the incorporation of NZO that enhanced the conducting nature, stability and surface area of PAPV-NZO. The optimum concentration of the dye and the adsorbent dosage of the PAPV-NZO were determined to be 80 ppm and 50 mg, respectively. At acidic condition of pH 2, the removal capacity of PAPV-NZO was found 99.6%. Kinetic and isotherm models have been studied on the optimum parameters to investigate the nature of the adsorption process. The process followed pseudo second order kinetics and was best suited to the Langmuir model. The maximum dye adsorption capacity of PAPV-NZO was estimated to be 159.36 mg g^-1. From the results, it can be assured that the PAPV-NZO can be effectively used for the removal of dye pollutants in water.

Self-regenerative and self-enhanced smart graphene/Ag3PO4 hydrogel adsorbent under visible light

We prepared a new 3D adsorbent that could be easily removed by filtration and recycled.

A new functionalized magnetic nanocomposite of poly(methylacrylate) for the efficient removal of anionic dyes from aqueous media

A magnetic nano-adsorbent was synthesized via the radical polymerization of methyl acrylate on modified Fe₃O₄ MNPs, followed by amidation of the methyl ester groups using pentaethylenehexamine, to create active sites for adsorption of anionic dyes.

Ultrasensitive detection of sulfide ions through interactions between sulfide ions and Au(iii) quenching the fluorescence of chitosan microspheres functionalized with rhodamine B and modified with Au(iii)

A rapid and facile fluorescence probe for detecting sulfide ions was developed. The probe can be completely regenerated and was easily separated. The approach described here is a new and convenient way of developing reusable fluorescence probes.

Effective removal of azo-dye orange II from aqueous solution by zirconium-based chitosan microcomposite adsorbent

In this study, zirconium-based chitosan (CTS@Zr) microcomposite was prepared and employed as an efficient adsorbent for the removal of orange II dye from aqueous solution.

Fabrication of degradable polymer microspheres via pH-responsive chitosan-based Pickering emulsion photopolymerization

Degradable polymer microspheres were facilely fabricated by chitosan-based Pickering emulsion photopolymerization.