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Wastewater containing dyes is frequently discharged by industrial processes and needs separation and recycling. To solve this problem, it is important to research and develop environmentally friendly, efficient adsorbent materials for pollutant separation and recovery. In this study, a poly(PEI‐catechol‐tetraethylenepentamine) (PPCT) adsorbent was synthesized using a simple catecholamine reaction. This adsorbent exhibited high adsorption capacity and excellent removal efficiency for Reactive Red 195 (RR‐195) in wastewater. The material was characterized using SEM, FT‐IR, TGA, EA, and XPS. Its performance was optimized by varying the type of polyethyleneimine and the amount added during the preparation process. The effects of temperature, pH, contact time, and salt concentration on the adsorption were systematically investigated. Additionally, the experimental data showed consistency with both the Langmuir and pseudo‐second‐order kinetic models, simultaneously. The maximum adsorption capacity can reach 1754 mg g−1 at 303 K, with a retention rate of 86.6% after two cycles. The removal rate exceeds 98% at a concentration of 400 mg g−1 or lower. Additionally, the protonated amine group in PPCT carries a positive charge under acidic conditions, enabling selective adsorption of the anionic dye RR‐195. Consequently, PPCT exhibits an excellent adsorption effect on RR‐195 and holds promising applications in pollutant removal. [ABSTRACT FROM AUTHOR]

In this work, a new AC@Catechol/PEI adsorbent was prepared via the copolymerization of catechol and polyethyleneimine (PEI) onto pretreated commercial activated carbon (AC). It achieved a high adsorption capacity of 411.52 mg/g for the anionic dye Congo red (CR), which was approximately 7 times that of pretreated AC without modification. In bath adsorption experiment, 1 g of adsorbent was used to treat 4 L of 100 mg/L CR solution, resulting in 98.5% CR removal. In addition, the prepared AC@Catechol/PEI adsorbent exhibited highly efficient CR competitive adsorption against SO42− ions and cationic malachite green dye. The adsorption mechanism was mainly attributed to electrostatic interactions, hydrogen bonding, and π–π stacking. Catecholamine modification greatly improved the adsorption capacity and adsorption selectivity of commercial AC for CR dyes. This low‐cost adsorbent may have broad prospects for the removal of anionic dyes in wastewater. [ABSTRACT FROM AUTHOR]

ABSTRACT A silica-sphere-poly(catechol hexamethylenediamine) (PCHA-SiO2) composite was prepared via the one-step facile polymerization of catechol and hexamethylenediamine; this method uses a silica sphere as a hard template. The chemical structures and morphologies of this composite were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy. The adsorption experiments indicated that the PCHA-SiO2 composite served as a very attractive adsorbent for Pb(II)-, Cu(II)-, and Cd(II)-ion removal at lower concentrations and had very good selective adsorption abilities for Pb(II) and Cu(II) ions in a solution contaminated with these three ions at higher concentrations. These interesting results may have been due to the reversible H+ adsorption-desorption properties of the characteristic phenol amine structure of the PCHA-SiO2 composite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45839. [ABSTRACT FROM AUTHOR]

In this article, poly[(dimethylamino)ethyl methacrylate] (PDMAEMA) brushes were grafted onto graphene oxide (GO) sheet via noncovalent modification of pyrene terminated initiator and subsequent in situ surface-initiated atom transfer radical polymerization (SI-ATRP). The results of zeta-potentials, dispersivity measurement as well as the permeability of cationic and anionic redox-active probe molecules reveal that the as-prepared GO/PDMAEMA composite exhibits zwitterionicity because of the presence of phenol hydroxyl, carboxyl, and amine groups and the charging state can be manipulated by controlling pH values. Furthermore, by ion exchange and in situ reduction, palladium and gold nanoparticles were successfully uploaded and the catalytic property of the uniformly distributed Pd-Au nanoparticles on GO sheet was investigated. These results reported in this work may open primarily toward constructing a bridge among GO, charged polymer and metal nanoparticles and secondarily to represent a new strategy for uniformly depositing inorganic nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Lignosulfonate‐based polycatecholamine (PCEA‐LS) was synthesized by a two‐stage approach involving Mannich and catechol–amine reactions, and it was directly used to adsorb Congo red (CR) from the pH‐unadjusted aqueous solution. PCEA‐LS was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), and X‐ray photoelectron spectroscopy (XPS). Various factors affecting on removal of CR by PCEA‐LS were investigated in depth, including contact time, adsorbent dosage, and initial concentration of CR and adsorption temperature. The adsorption kinetics, isotherm, and thermodynamics of PCEA‐LS for CR were explored in detail, and then its adsorption mechanism was systematically elucidated. Results indicated that the removal process of CR followed the pseudo‐second‐order kinetic model, and the isotherm data fitted the Langmuir model well. The maximum adsorption capacity reached 972.6 mg g−1 at 30°C in the pH‐unadjusted (pH = 6.25) solution possibly due to the hydrogen bond, π–π stacking, and electrostatic interaction between PCEA‐LS and CR. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48640. [ABSTRACT FROM AUTHOR]

Synthesis of covalently linked porous polymers with high surface area and larger pore volume for two or more task‐specific functionalities is always a big challenge. In this article, the facile Friedel–Crafts reaction is employed to construct the hierarchical hybrid porous polymers (HPPs) from tetraphenyladamantane and octavinylsilsesquioxane. The resulting polymers, HPP‐1 to HPP‐3, possessed the surface areas from 1356 to 1511 m2 g−1, and the pore volumes from 2.05 to 2.67 cm3 g−1. All these polymers feature micropores, mesopores, and macropores in nature. The resultant polymers exhibit high CO2 adsorption capacity up to 2.0 mmol g−1 (8.82 wt %), at 273 K, 1.0 bar, and the maximum Rhodamine B (RB) sorption capacity of 653.6 mg g−1. To illustrate the adsorption process, the effects of factors, contact time, initial concentration, temperature, and pH value on the adsorption capacity of RB were studied. The adsorption equilibrium data displayed a better fitting to the Langmuir isotherm model than the Freundlich model and the adsorption kinetics fitted well with the pseudo‐second‐order kinetic model. The recycle experiments displayed that the capacity recovery was still higher than 95% after four cycles. Theses polymers are promising to be the adsorbents for capturing CO2 and removing RB. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 136, 48572. [ABSTRACT FROM AUTHOR]