NOx storage and reduction assisted by non-thermal plasma over Co/Pt/Ba/γ-Al2O3 catalyst using CH_(4) as reductant

NOx storage and reduction(NSR)technology has been regarded as one of the most promising strategies for the removal of nitric oxides(NOx)from lean-burn engines,and the potential of the plasma catalysis method for NOx reduction has been confirmed in the past few decades.This work reports the NSR of nitric oxide(NO)by combining non-thermal plasma(NTP)and Co/Pt/Ba/γ-Al2O3(Co/PBA)catalyst using methane as a reductant.The experimental results reveal that the NOx conversion of NSR assisted by NTP is notably enhanced compared to the catalytic efficiency obtained from NSR in the range of 150°C–350°C,and NOx conversion of the 8%Co/PBA catalyst reaches 96.8%at 350°C.Oxygen(O_(2))has a significant effect on the removal of NOx,and the NOx conversion increases firstly and then decreases when the O_(2)concentration ranges from 2%to 10%.Water vapor reduces the NOx storage capacity of Co/PBA catalysts on account of the competition for adsorption sites on the surface of Co/PBA catalysts.There is a negative correlation between sulfur dioxide(SO_(2))and NOx conversion in the NTP system,and the 8%Co/PBA catalyst exhibits higher NOx conversion compared to other catalysts,which shows that Co has a certain SO_(2)resistance.

Removal of virus aerosols by the combination of filtration and UV-c irradiation

The COVID-19 pandemic remains ever prevalent and afflicting—partially because one of its transmission pathways is aerosol.With the widely used central air conditioning systems worldwide,indoor virus aerosols can rapidly migrate,thus resulting in rapid infection transmission.It is therefore important to install microbial aerosol treatment units in the air conditioning systems,and we herein investigated the possibility of combining such filtration with UV irradiation to address virus aerosols.Results showed that the removal efficiency of filtration towards f2 and MS2 phages depended on the type of commercial filter material and the filtration speed,with an optimal velocity of 5 cm/s for virus removal.Additionally,it was found that UV irradiation had a significant effect on inactivating viruses enriched on the surfaces of filter materials;MS2 phages had greater resistance to UV-C irradiation than f2 phages.The optimal inactivation time for UV-C irradiation was 30 min,with higher irradiation times presenting no substantial increase in inactivation rate.Moreover,excessive virus enrichment on the filters decreased the inactivation effect.Timely inactivation is therefore recommended.In general,the combined system involving filtration with UV-C irradiation demonstrated a significant removal effect on virus aerosols.Moreover,the system is simple and economical,making it convenient for widespread implementation in air-conditioning systems.

Removing and recycling mercury from scrubbing solution produced in wet nonferrous metal smelting flue gas purification process

Wet purification technology for nonferrous metal smelting flue gas is important for mercury removal;however, this technology produces a large amounts of spent scrubbing solution that contain mercury. The mercury in these scrubbing solutions pose a great threat to the environment. Therefore, this research provides a novel strategy for removing and recycling mercury from the scrubbing solution, which is significant for decreasing mercury pollution while also allowing for the safe disposal of wastewater and a stable supply of mercury resources. Some critical parameters for the electrochemical reduction of mercury were studied in detail. Additionally, the electrodeposition dynamics and electroreduction mechanism for mercury were evaluated. Results suggested that over 92.4% of mercury could be removed from the scrubbing solution in the form of a Hg-Cu alloy under optimal conditions within 150 min and with a current efficiency of approximately 75%. Additionally, mercury electrodeposition was a quasi-reversible process, and the controlled step was the mass transport of the reactant. A pre-conversion step from Hg(Tu)_(4)^(2+) to Hg(Tu)_(3)^(2+) before mercury electroreduction was necessary. Then, the formed Hg(Tu)_(3)^(2+) on the cathode surface gained electrons step by step. After electrodeposition, the mercury in the spent cathode could be recycled by thermal desorption. The results of the electrochemical reduction of mercury and subsequent recycling provides a practical and easy-to-adopt alternative for recycling mercury resources and decreasing mercury contamination.

Enhanced activation of peroxydisulfate by strontium modified BiFeO3 perovskite for ciprofloxacin degradation

A series of Sr-doped BiFeO3 perovskites(Bi1-xSrxFeO3,BSFO)fabricated via sol-gel method was applied as peroxydisulfate(PDS)activator for ciprofloxacin(CIP)degradation.Various technologies were used to characterize the morphology and physicochemical features of prepared BSFO samples and the results indicated that Sr was successfully inserted into the perovskites lattice.The catalytic performance of BiFeO3 was significantly boosted by strontium doping.Specifically,Bi0.9Sr0.1FeO3(0.1 BSFO)exhibited the highest catalytic performance for PDS activation to remove CIP,where 95%of CIP(10 mg/L)could be degraded with the addition of 1 g/L 0.1 BSFO and 1 mmol/L PDS within 60 min.Moreover,0.1 BSFO displayed high reusability and stability with lower metal leaching.Weak acidic condition was preferred to neutral and alkaline conditions in 0.1 BSFO/PDS system.The boosted catalytic performance can be interpreted as the lower oxidation state of Fe and the existence of affluent oxygen vacancies generated by Sr doping,that induced the formation of singlet oxygen(^1O_(2))which was confirmed as the dominant reactive species by radical scavenging studies and electron spin resonance(ESR)tests.The catalytic oxidation mechanism related to major ^1O_(2) and minor free radicals was proposed.Current study opens a new avenue to develop effective A-site modified perovskite and expands their application for PDS activation in wastewater remediation.