Herein, an electroactive filtration system, consisting of a Ti4O7 anode and a Pd-Cu co-modified nickel foam cathode, was developed and applied for the decontamination of ammonia from water. When assisted with an external electrical field, ClO• was generated on the surface of the Ti4O7 anode, which then reacted selectively with ammonia to generate N2. The anodic byproduct, NO3−, could also be reduced efficiently at the functional cathode to produce N2 as well. Electron paramagnetic resonance technique and radical scavenging tests synergistically verified the essential role of ClO• during the highly efficient ammonia conversion process. Relative to conventional batch systems, the developed flow-through design demonstrated enhanced ammonia conversion kinetics, thanks to the convection-enhanced mass transport. The proposed technology also showed desirable stability across a wide environmental matrix. This work provides new insights for the development of advanced and affordable continuous-flow systems towards effective decontamination of ammonia.
Herein, we report and demonstrate a photoelectrochemical filtration system that enables the effective decontamination of micropollutants from water. The key to this system was a photoelectric–active nanohybrid filter consisting of a carbon nanotube (CNT) and MIL–101(Fe). Various advanced characterization techniques were employed to obtain detailed information on the microstructure, morphology, and defect states of the nanohybrid filter. The results suggest that both radical and nonradical pathways collectively contributed to the degradation of antibiotic tetracycline, a model refractory micropollutant. The underlying working mechanism was proposed based on solid experimental evidences. This study provides new insights into the effective removal of micropollutants from water by integrating state–of–the–art advanced oxidation and microfiltration techniques.
Decolorization of malachite green (MG) from the aqueous phase was investigated using tea stalk powder. The adsorption efficiency decreased with the initial MG concentration, ionic strength of the solution, and heavy metal content. A suitable initial MG concentration of up to 200 mg/L can be accepted because adsorption efficiency of more than 95% is achieved. Various adsorption kinetic models were used to fit the experimental data, and the data obtained was best explained by the pseudo second-order model. The adsorption capacities calculated with the pseudo second-order model at different initial MG concentrations ranging from 24.27 to 158.7 mg/g were very close to the experimental data. The Langmuir isotherm fitted well, and the thermodynamic investigation showed that the adsorption of MG by tea stalk powder was feasible, endothermic, and spontaneous. The regeneration/adsorption experiments indicated that the tea stalk powder remained more than 95% of efficiency after six cycles using NaOH as desorbent and thus could be used many times. In conclusion, tea stalk has considerable potential as a cost-effective adsorbent for the removal of MG.
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