Mesoporous polymer systems based on divinylbenzene copolymers modified with linear rubbers

Porous carbon black-polymer composites for volatile organic compound adsorption and efficient microwave-assisted desorption

Adsorbents with high surface area, thermal stability and microwave absorption ability are highly desired for cyclic adsorption and microwave regeneration processes. However, most polymeric adsorbents are transparent to microwaves. Herein, porous hyper-crosslinked polymers (HCP) of (4,4'-bis((chloromethyl)-1,1'-biphenyl-benzyl chloride)) with different carbon black (CB) contents were synthesized via the Friedel-Crafts reaction. CB was selected as the filler due to its low cost and high dielectric loss and was embedded inside the polymer structure during polymerization. CB-containing composites showed enhanced thermal stability at elevated temperatures, and more than a 90-times increase in the dielectric loss factor, which is favorable for microwave regeneration. Nitrogen physisorption analysis by the Bruner-Emmett-Teller isotherms demonstrated that CB presence in the polymer structure nonlinearly decreases the surface area and total pore volume (by 38% and 26%, respectively at the highest CB load). Based on the characterization testing, 4 wt% of CB was found to be an optimum filler content, having the highest MW absorption and minimal effect on the adsorbent porosity. HCP with 4 wt% CB allowed a substantial increase in the desorption temperature and yielded more than a 450% enhancement in the desorption efficiency compared to HCP without CB.

A novel surface imprinted resin for the selective removal of metal-complexed dyes from aqueous solution in batch experiments: ACB GGN as a representative contaminant

Metal-complexed dyes are harmful to the environment and human health because they contain heavy metals and complex organic ligands. It is difficult to separate and recover these dyes from wastewater owing to their complex components and poor selectivity of common adsorbents. In this study, a novel surface molecularly imprinted polymer (SMIP) was prepared using 4-vinyl pyridine as the functional monomer and polystyrene resin as the carrier. SMIP showed better adsorption performance than non-imprinted polymer (SNIP) in the whole pH range with the best adsorption capacity at pH 1.5. The correlation coefficients (R²) fitted by Langmuir and Temkin models were greater than 0.97, and the adsorption was a spontaneous exothermic process. The pseudo-second-order and Elovich models fitted the adsorption kinetic curves well. The adsorption capacity of SMIP was approximately 20% higher than that of SNIP in the salt concentration ranging from 2 to 80 mg/L. In selective adsorption experiments, the relative selectivity coefficients (I) of SMIP for competitors were all greater than 2.41, and the Cr (Ⅲ) components of ACB GGN played a more important role in the recognition performance of SMIP than the sulfonic groups. Adsorption mechanism tests revealed that although the adsorption of ACB GGN by SMIP mainly relied on electrostatic attraction, hydrophobic interactions, π-π conjugation, and Cr (Ⅲ) coordination were also involved. These results show that SMIP has excellent selective adsorption properties for ACB GGN and a promising application potential in the treatment of metal-complexed dye wastewater.