Adsorption and separation behaviors of Y(III) and Sr(II) in acid solution by a porous silica based adsorbent

Phosphination of amino-modified mesoporous silica for the selective separation of strontium

Radioactive strontium (90Sr) is considered as one of the most dangerous radionuclides due to its high biochemical toxicity. For the efficient and selective separation of Sr from acidic environments, a novel functional adsorbent CEPA@SBA-15-APTES was prepared in this work through the phosphorylation of amino-modified mesoporous silica with organic content of approximately 20 wt%. CEPA@SBA-15-APTES was characterized by TEM, SEM, EDS, TG-DSC, BET, FTIR, and XPS techniques, revealing its characteristics of an ordered hexagonal lattice-like structure and rich functional groups. The experimental results demonstrated that the adsorbent exhibited good adsorption capacity for Sr over a wide acidity range (i.e., from 10-10 M to 4 M HNO3). The adsorption equilibriums of Sr by CEPA@SBA-15-APTES in 10-6 M and 3 M HNO3 solutions were reached within 30 and 5 min, respectively, and the adsorption capacities at 318 K were 112.6 and 71.8 mg/g, respectively. Furthermore, by combining the experimental and characterization results, we found that the adsorption mechanism consisted of ion exchange between Sr(II) and H+ (in P-OH) in the 10-6 M HNO3 solution and coordination between the Sr(II) and oxygen-containing (CO and P = O) functional groups in the 3 M HNO3 solution.

Utilization of Low Cost Biofertilizers for Adsorptive Removal of Congo Red Dye

Presence of colors, organic surface finishing agents and surfactants in textile industry effluent makes it highly detrimental for surrounding environment. Hence the effluent from textile industry needs treatment for removal of these colors, organic and inorganic components before its disposal. Hence applicability of low cost and environmental friendly biosorbents, Azospirillium biofertilizer and Rhizobium biofertilizer were investigated for removal of Congo red dye. Batch experimentation was carried out to check operating parameters like, temperature, dose of adsorbent, pH, agitation speed, contact time and initial concentration. The biosorption capacity for Congo red dye was 67.114 and 101.01 mg/g, for Azospirillium biofertilizer and Rhizobium biofertilizer, respectively at optimized parameters. RL factor was 0.558 and 0.568 for Azospirillium biofertilizer and Rhizobium biofertilizer. The data showed combination of interaction-based separation through better fitting of Langmuir isotherm compared to Freundlich. Its separation is well described by Pseudo-second order and intraparticle diffusion model. Adsorption was favorable at lower temperature suggesting exothermic and spontaneous nature. Reusability for Azospirillium biofertilizer and Rhizobium biofertilizer was checked for 25 mg/land. While the biological nature of Azospirillium and Rhizobium biofertilizer makes removal of Congo red dye environmentally benign.

Rational fabrication of a new ionic imprinted carboxymethyl chitosan-based sponge for efficient selective adsorption of Gd(iii)

In this work, a new PEI-CMC-IIS adsorbent with 3D network structure was fabricated for the selective adsorption of Gd(iii).

Adsorption of N,N,N′,N′-Tetraoctyl Diglycolamide on Hypercrosslinked Polysterene from a Supercritical Carbon Dioxide Medium

The work considers for the first time the preparation of sorbents based on hypercrosslinked polysterene (HCP) and chelating agent N,N,N′,N′-tetraoctyl diglycolamide (TODGA) by impregnation in the supercritical (SC) CO₂ medium. Such sorbents can be applied for further isolation and separation of lanthanides, actinides and other metals. They are usually prepared by impregnation in toxic organic solvents (e.g., methanol, dichloromethane). Our study shows that application of SC CO₂ instead of organic solvents can significantly speed up the impregnation, perfom it in one stage and make the process more eco-friendly. At the same time, the obtained sorbents are close in their parameters to the classical ones. This article presents the results of measuring the TODGA adsorption isotherms on two HCP sorbents (MN202 and MN270) on a wide range of SC fluid parameters. Adsorption measurements were carried out using on-line supercritical fluid chromatography and gravimetry. Based on the sorption capacity parameter, MN202 sorbent was selected as the better carrier for TODGA. An impregnation temperature increase within the range 313–343 K in isochoric conditions (ρ = 0.780 g/mL) reduces the maximum of TODGA adsorption from ~0.68 mmol/g to ~0.49 mmol/g.