Jirui Yang,Xinhua Qi,Feng Shen,Mo Qiu,Richard Lee Smith
Transfer hydrogenation is highly effective for dechlorinating priority organic pollutants in wastewater. Lindane could be completely dechlorinated at room temperature and atmospheric pressure via transfer hydrogenation, in which Pd (3.1 wt%) supported on chitosan-derived porous carbon (3.1Pd@A600) and formic acid (FA) were used as catalyst and hydrogen source, respectively. Favorable catalytic activity of 3.1Pd@A600 is attributed to pyridinic N of the support that allowed Pd nanoparticles to be well-dispersed in the solid and to pyridinic N-Pd interactions that enhanced FA decomposition over that observed for commercial carbon supported Pd catalyst (5Pd@AC). In the reaction system containing 3.1Pd@A600 and FA, 99.7% lindane conversion and 100% dechlorination efficiency could be achieved at 25 °C and atmospheric pressure within 60 min. Benzene and cyclohexane were identified as end-products of lindane dechlorination . The transfer hydrogenation strategy developed in this study has wide application to chlorinated organic pollutants contained in actual waste streams.
The capacitive deionization technology has demonstrated its efficacy in removing chlorine-containing contaminants from water. However, the long-term and selective removal of Cl − remains a significant challenge. We present the synthesis of nitrogen‑phosphorus co-doped carbon composites embedded with silver-metal particles by incorporating N and P heteroatoms, which serve as effective anchoring sites for metallic Ag. The design of the electrode material ultimately enhances the electrochemical stability of silver by facilitating strong interactions between nitrogen and phosphorus with the silver and carbon substrates, respectively, forming stable chemical bonds. The electrode material exhibited excellent dechlorination performance, with a selectivity factor (Cl − versus SO 4 2− ) of up to 83.4 for Cl − in wastewater in a mixed solution and an adsorption capacity of 99.2 mg·g −1 for Cl − . Additionally, the silver-based selective dechlorination electrode achieved a desalination capacity of 77.7 mg·g −1 for Cl − in a single system and demonstrated remarkable stability over 100 cycles, retaining 93.99 % of its capacity. The present study demonstrates that introducing nitrogen and phosphorus can significantly enhance the cyclic stability of silver‑carbon electrodes, thereby facilitating the sustainable treatment of chlorinated wastewater.
Anion exchange membranes polypyrrole-modified(PPy-M), polypyrrole-graphene oxide-modified(PPy-GO-M), and polypyrrole-polyethyleneimine-graphene oxide-modified(PPy-PEI-GO-M) were synthesized using in situ polymerization for advanced desulfurization wastewater treatment and cathodic scaling inhibition in membrane electrolysis(ME). Characterization by SEM-EDX(scanning electron microscope-energy-dispersive X-ray spectroscopy), AFM(Atomic force microscopy), FT-IR(Fourier-transform micro-infrared spectrometer), XPS(X-ray photoelectron spectroscopy), and Raman spectroscopy revealed the membranes morphology and chemical properties, and their basic performances, including ion exchange capacity, water uptake, contact angle, zeta potential,perm-selectivity, and the membrane resistance, were rough analyzed. PPy-PEI-GO-M showed the best performance, with an ion exchange capacity of 2.57 mmol g -1 , contact angle of 85°, zeta potential of +15.59mV, membrane resistance of 6.97 Ω cm 2 , and perm-selectivity of 98%. Under optimal electrolysis conditions (ME time 180 min, temperature 30°C, current density 40 mA cm -2 , electrode spacing 4 cm), it achieved a Cl - removal rate of 96.83% without cathodic scaling, with treated effluent successfully reused in a flue gas desulfurization system. This modified membrane shows strong potential for water treatment applications.
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