The COVID-19 pandemic has an adverse effect on the environment. This epidemic’s effect on the waste composition and management and the impacts of municipal solid waste management (MSWM) on disease ...transmission or controlling are considered a compelling experience of living in the COVID-19 pandemic that can effectively control the process. This systematic review research was conducted to determine the effects of COVID-19 on the quantity of waste and MSWM. Searches were conducted in three databases (using keywords covid 19, coronaviruses, and waste), and among the published articles from 2019 to 2021, 56 ones were selected containing information on the quantity and waste management during the COVID-19 pandemic. The results showed that COVID-19 caused the quantity variation and composition change of MSW. COVID-19 also has significant effects on waste recycling, medical waste management, quantity, and littered waste composition. On the other hand, the COVID-19 pandemic has changed waste compounds’ management activities and waste generation sources. Recognizing these issues can help plan MSWM more efficiently and reduce virus transmission risk through waste.
Abstract In this study, TiO 2 nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO 2 nanoparticles were decorated on ...natural pyrite (TiO 2 /NP) and characterized using XRD, FTIR, and SEM–EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm 2 ), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be · OH radicals in the TiO 2 /NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO 2 /NP system has high performance in photocatalytic TC removal under optimized experimental conditions.
In this study, the photocatalytic activity of ZnO was effectively improved via its combination with spinel cobalt ferrite (SCF) nanoparticles. The catalytic performance of ZnO@SCF (ZSCF) was ...investigated in coupling with UV irradiation and ultrasound (US), as a heterogeneous sono-photocatalytic process, for the decontamination of phenanthrene (PHE) from contaminated soil. Soil washing tests were conducted in a batch environment, after extraction assisted by using Tween 80. Several characterization techniques such as XRD, FESEM-EDS, BET, TEM, UV–vis DRS, PL and VSM were utilized to determine the features of the as-prepared catalysts. ZSCF showed an excellent catalytic activity toward degradation of PHE in the presence of US and UV with a significant synergic effect. It was found that more than 93% of PHE (35 mg/L) and 87.5% of TOC could be eliminated by the integrated ZSCF/US/UV system under optimum operational conditions (pH: 8.0, ZSCF: 1.5 g/L, UV power: 6.0 W and US power: 70 W) within 90 min of reaction. After five times of use, ZSCF illustrated good reusability in the decontamination of PHE (87%) and TOC (79%). Quenching tests revealed the contribution of h+, HO• and e− species during PHE degradation over ZSCF/UV/US and an S-scheme photocatalytic mechanisms was proposed for the possible charge transfer routes under the ZSCF system. This study provides the important role of SCF in enhancing the ZnO photocatalytic activity due to its high performance, easy recovery and excellent durability, which it make an efficient and promising catalyst in environmental clean-up applications.
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•UV-assisted ZSCF was combined with US irradiation towards PHE degradation.•A significant synergy effect was observed between ZSCF, UV, and US for PHE removal.•The removal efficiencies of 93.8 and 87.5% were attained for PHE and TOC under optimum conditions.•Photocatalysis process was attributed to S-scheme heterojunction mechanism.
Developing heterogeneous catalysts with high performance for peroxymonosulfate (PMS) activation to decontaminate organic pollutants from wastewater is of prominent importance. In this study, spinel ...cobalt ferrite (CoFe2O4) materials were coated on the surface of powdered activated carbon (CoFe2O4@PAC) via the facile co-precipitation method. The high specific surface area of PAC was beneficial for the adsorption of both bisphenol A (BP-A) and PMS molecules. The CoFe2O4@PAC-mediated PMS activation process under UV light could effectively eliminate 99.4% of the BP-A within 60 min of reaction. A significant synergy effect was attained between CoFe2O4 and PAC towards PMS activation and subsequent elimination of BP-A. Comparative tests demonstrated that the heterogeneous CoFe2O4@PAC catalyst had a better degradation performance in comparison with its components and homogeneous catalysts (Fe, Co, and, Fe + Co ions). The formed by-products and intermediates during BP-A decontamination were evaluated using LC/MS analysis, and then a possible degradation pathway was proposed. Moreover, the prepared catalyst exhibited excellent performance in recyclability with slight leaching amounts of Co and Fe ions. A TOC conversion of 38% was obtained after five consecutive reaction cycles. It can be concluded that the PMS photo-activation process via the CoFe2O4@PAC catalyst can be utilized as an effective and promising method for the degradation of organic contaminants from polluted-water resources.
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•CoFe2O4 was anchored on PAC and used as a PMS activator to degrade BP-A.•CoFe2O4@PAC catalyst exhibited better performance than homogeneous catalysts towards BP-A degradation.•CoFe2O4@PAC/PMS/UV eliminated 99.4% and 49.5% of BP-A and TOC, respectively.•The plausible BP-A degradation pathway was proposed based on the produced intermediates.•CoFe2O4@PAC had an excellent performance in recyclability with slight leaching of metal ions.
In this study, the photocatalytic degradation of toluene through zinc oxide (ZnO) nanoparticles coated on glass plates was examined under simulated sunlight. Heat attachment procedure was employed to ...immobilize ZnO nanoparticles on glass plates. Removal performance of these prepared plates for toluene degradation was evaluated in a rectangular reactor under irradiation of metal halide lamp. The effects of operational parameters including initial toluene concentration, temperature, relative humidity, irradiation time, and concentration of zinc oxide suspension on the removal of toluene were investigated. The structural properties of ZnO nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The concentration of toluene was analyzed by gas chromatography with flame ionization detector (GC-FID). The results of the present study indicated that ZnO-coated glass plates resulted in removal of 67% toluene for concentration of 50 ppm at temperature 45 °C, and relative humidity of 40% after 240 min irradiation of metal halide light. As the glass plates coated by ZnO have relatively good performance under experimental conditions, it concluded that coating ZnO nanoparticles on surfaces can be considered as an environmentally friendly method to eliminate low concentration of toluene from polluted air under sunlight.
A heterogeneous photocatalyst, ZnO/reduced graphene oxide (ZnO/rGO or ZG), was synthesised for the photocatalytic degradation of metalaxyl (MX) in aqueous solutions under UV irradiation. The ...characteristics of the prepared catalyst were determined by FTIR, XRD, FE-SEM, EDS, and BET analyses. The effect of various parameters such as solution pH, catalyst concentration, rGO loading in the catalyst structure, MX concentration and UV light intensity on the photodegradation of MX was investigated. The concentration of MX and the toxicity of the intermediates were determined by HPLC and the Daphnia Magna toxicity test, respectively. The effect of the water anions and radical scavenger compounds on the MX removal process was studied as well. The rate of mineralisation was determined by measuring the total organic carbon (TOC) value using the TOC analyser. The efficiency of the degradation process was compared with the real sample of agricultural drainage and deionised water. At optimum conditions (pH = 7, catalyst loading = 10%, catalyst concentration = 0.75 g/l, MX concentration = 10 mg/l, and UV intensity = 220 MW/cm
2
), the removal and mineralisation rates were 90.25% and 51.17% after 120 min, respectively. Reactive species scavenging experiments showed that the hole was the most effective factor for MX degradation in the ZG/UV process. The MX degradation rate in real agricultural run-off samples showed that the degradation efficiency was 50.42%, which was significantly lower than that of the synthetic samples. The toxicity bioassay by D. Magna indicated that the toxicity of MX was reduced from 51.22 to 15.17 after 96 h during the ZnO/rGO process. The photocatalytic efficiency decreased in the presence of phosphate and nitrate ions but did not change much in the presence of other water anions. Thus, the ZG/UV process can be effectively used for the degradation of organic pollutants, especially pesticides in wastewater.
The photocatalytic oxidation of benzene by ZnO nanoparticles coated on glass plates was studied under simulated sunlight. ZnO nanoparticles were coated on three glass plates by heat attachment ...method. To evaluate the photocatalytic removal of benzene, coated plates were irradiated by metal halide lamp in a rectangular reactor in batch mode. The effect of initial pollutant concentration, temperature, relative humidity, irradiation time, concentration of zinc oxide suspension, were assessed. The surface morphology and structure of ZnO nanoparticles and ZnO coated on glass plates were characterized by scanning electron microscopy, X-ray diffraction and field emission scanning electron microscopy. Sampling and analysis of benzene were performed according to NIOSH method. To analyze the concentration of benzene, gas chromatography with flame ionization detector (GC-FID) was used. Results indicated that photocatalytic process by ZnO under irradiation of metal halide lamp could remove benzene at optimum experimental conditions. Coating of glass plates by ZnO suspension, resulted in 57% removal of benzene as concentration of 50 ppm at 45 °C, and relative humidity of 40% after 240 min irradiation of metal halide lamp. Results indicated that photocatalytic oxidation process by ZnO nanoparticles can be used as a proper and environmentally friendly method for removing low concentrations of benzene from polluted air under simulated sunlight.
Background and Objective: Pharmaceutical compounds can cause potential risks to aquatic and terrestrial organisms. So far, different methods have been used to eliminate these pollutants, ...photocatalytic processes are one of the most efficient processes to eliminate pharmaceutical compounds. In this study, the efficiency of a novel MOF-based nanocomposite, PMo/UiO-66 as a photocatalyst for amoxicillin degradation under visible light irradiation was evaluated. Materials and Methods: The study of the chemical decomposition of amoxicillin using the PMo/UiO-66 system was conducted at different stages. First, the PMo/UiO-66 MOF nanocomposite was synthesized using the solvothermal method, then the properties of the synthesized nanocomposite were investigated using XRD, FTIR, and SEM techniques. The effect of different operational parameters such as pH (3, 6, and 9), catalyst concentration (15, 20, 25, and 30 %w/w), initial concentrations of amoxicillin (20, 30, 40, and 50 mg/L) at different times on the removal efficiency was investigated. The reusability of the catalyst for four cycles was assessed. Results: The results showed that PMo/UiO-66 nanocomposite at pH 6, 25 %w/w nanocomposite concentration, and the amoxicillin concentration of 20 mg/L led to complete decomposition of amoxicillin after 120 min. The kinetic of amoxicillin removal followed the first-order model. Reusability tests showed that the photocatalytic efficiency of the synthesized catalyst was not substantially reduced after four cycles. Conclusion: The current study confirmed that the PMo/UiO-66 system has an appropriate efficiency for photocatalytic removal of amoxicillin under optimized test conditions.
For this data article the photocatalytic oxidation of benzene and toluene by ZnO nanoparticles coated on glass plates were studied under simulated sunlight. ZnO nanoparticles were coated on three ...glass plates by heat attachment methods. To evaluate the photocatalytic removal of benzene and toluene, coated plates irradiated by metal halide lamp in a rectangular reactor in batch mode. The effect of initial pollutants concentration, temperature, relative humidity, irradiation time, concentration of zinc oxide suspension, were assessed. The surface morphology and structure of ZnO nanoparticles and ZnO coated on glass plates were characterized by scanning electron microscopy, X-ray diffraction and Field Emission Scanning Electron Microscopy. Sampling and analysis of pollutants were performed according to the National Institute for Occupational Safety and Health (NIOSH) method. To analyze the concentration of benzene and toluene, gas chromatography with flame ionization detector (GC-FID) was used. The data results indicated that photocatalytic process by ZnO under irradiation of metal halide lamp could remove benzene and toluene at optimum experimental conditions. Coating of glass surfaces by ZnO suspension, resulted in 46% and 57% removal of benzene and toluene as concentration of 50 ppm at 45 °C, and relative humidity of 40% after 240 min irradiation of metal halide lamp.
In this study, TiO
nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO
nanoparticles were decorated on natural pyrite (TiO
.../NP) and characterized using XRD, FTIR, and SEM-EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm
), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be
OH radicals in the TiO
/NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO
/NP system has high performance in photocatalytic TC removal under optimized experimental conditions.
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