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Porous organic polymers (POPs) with high Brunauer-Emmett-Teller (BET) surface area (S BET) and plentiful heteroatoms are promising for CO 2 capture and separation. Herein a series of melamine-based porous polyamides were synthesized from melamine and binary/ternary benzoic acid by one-pot polycondensation strategy. These polymers have considerably high S BET (up to 521 m2/g) and enriched nitrogen (13.8–44.9 wt%). Importantly, they possess noteworthy CO 2 uptake (0.53–2.9 mmol/g at 273 K and 1 bar), the synergistic effect of predominant microporosity and abundant nitrogen are beneficial. Moreover, they have moderate isosteric heats (Q st) (29.5–43.7 kJ/mol) and acceptable CO 2 /N 2 selectivity (IAST: 31.6–277.8), which are highly relevant to the micropore volume, micropore area, and nitrogen content. Image 1 • A series of melamine-based porous polyamides were facilely prepared by one-pot synthesis without catalyst. • These polyamides with abundant nitrogen content had much higher surface areas compared to previous polyamides. • Their porosity and nitrogen content were carefully controlled via a simple and effective approach. • The well-defined microporosity and abundant nitrogen give them outstanding CO 2 capture. • The CO 2 adsorption was highly dependent on the V micro /V total. [ABSTRACT FROM AUTHOR]

The O-containing hyper-cross-linked polymers were synthesized from phenol (2-naphthol) and formaldehyde dimethyl acetal by a simple one-step Friedel-Crafts reaction, they were subsequently carbonized using KOH as the activating agent, and their adsorption to CO 2 was carefully tested. The results indicated that these samples had a high Brunauer-Emmett-Teller surface area (up to 2241 m 2 /g), pore volume (up to 1.20 cm 3 /g), CO 2 uptake (up to 6.3 mmol/g at 273 K and 1.0 bar), and CO 2 /N 2 selectivity (up to 96 for the HCPs, and 22.5 for the porous carbon). In particular, the CO 2 adsorption was highly dependent on the ultramicropore volume (pore width<0.7 nm), while the CO 2 /N 2 selectivity mainly relied on the oxygen content and the ultramicropore structure. [ABSTRACT FROM AUTHOR]

Novel quaternary ammonium/magnetic graphene oxide composites (M-PAS-GO) that efficiently remove Cr(VI) ions were fabricated through the introduction of the (3-aminopropyl) triethoxysilane and Fe3O4 nanoparticles on the surface of GO, and then modified with n-butyl bromide. The fabricated M-PAS-GO was comprehensively characterized by SEM, TEM, EDX, XRD, Raman spectroscopy and FTIR, and the results manifest that the quaternary ammonium group was introduced onto the surface of GO. Under the reaction conditions of pH 3.20, temperature of 25 °C and M-PAS-GO dosage of 0.01 g/50 mL, 90% of 10 mg/L Cr(VI) ions were removed from the solution within 20 min. The kinetics study indicates that the adsorption process followed the pseudo-second-order model and was surface reaction-controlled. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggest that the adsorption process was an exothermic and spontaneous process. The maximum adsorption capacities of Cr(VI) ions on M-PAS-GO composites calculated by the Langmuir model were 46.48 mg/g. Moreover, the reusability and stability of M-PAS-GO demonstrates its economic sustainability. This study suggests that M-PAS-GO is a potential candidate adsorbent for the separation of Cr(VI) from wastewater. [ABSTRACT FROM AUTHOR]