ABSTRACT
Advanced oxidation processes are a desirable technology for treatment of contaminants of emerging concern. Nevertheless, conventional advanced oxidation of organophosphorus compounds releases inorganic phosphate, posing downstream concerns related to eutrophication. For this reason, we evaluated the ultraviolet light-activated calcium peroxide (UV/CaO2) system for effective treatment of organophosphorus compounds and concurrent capture of the mineralization products, phosphate. The degradation mechanisms, reaction kinetics, and mineralizations were assessed to determine the overall efficiency and performance of the UV/CaO2 process. Knowledge gaps related to photocatalysis in the UV/CaO2 system were not only addressed, but also leveraged to identify unique advantages for removal of organophosphorus compounds and their degradation products. Experimental results confirmed that the UV/CaO2 system effectively mineralized organophosphorus compounds and recovered inorganic phosphate; additionally, collaborative carbon fixation performance of the system reveals the potential of carbon utilization. These outcomes were facilitated by the alkaline environment generated by CaO2. The recovered solids contained most of the phosphorus and carbon from the parent compounds. Ultimately, these findings provide transformative, new insights into the development and application of advanced oxidation processes that prevent downstream concerns related to mineralization products, especially inorganic phosphorus and carbon.
ABSTRACT
The widespread contamination of hexavalent chromium (Cr(VI)), pharmaceuticals and personal care products (PPCPs), and dyes is a growing concern. necessitating the development of convenient and effective technologies for their removal. Copper(I) phenylacetylide (PhC2Cu) has emerged as a promising photocatalyst for environmental remediation. In this study, we introduced a functional Cu-O bond into PhC2Cu (referred to as OrPhC2Cu) by creatively converting the adsorbed oxygen on the surface of PhC2Cu into a Cu-O bond to enhance the efficiency of Cr(VI) photoreduction, PPCPs photodegradation, and dyes photodegradation through a facile vacuum activating method. The incorporation of the Cu-O bond optimized the electron structure of OrPhC2Cu, facilitating exciton dissociation and charge transfer. The exciton dissociation behavior and charge transfer mechanism were systematically investigated for the first time in the OrPhC2Cu system by photoelectrochemical tests, fluorescence and phosphorescence (PH) techniques, and density functional theory (DFT) calculations. Remarkably, the enhanced visible-light response of OrPhC2Cu improved photon utilization and significantly promoted the generation of reactive species (RSs), leading to the highly efficient Cr(VI) photoreduction (98.52% within 25 min) and sulfamethazine photodegradation (94.65% within 60 min), with 3.91 and 5.23 times higher activity compared to PhC2Cu. Additionally, the photocatalytic efficiency of OrPhC2Cu in degrading anionic dyes surpassed that of cationic dyes. The performance of the OrPhC2Cu system in treating electroplating effluent or natural water bodies suggests its potential for practical applications.
ABSTRACT
In response to antibiotic residues in the water, a novel advanced oxidation technology based on MgO2 was used to remediate sulfamethazine (SMTZ) pollution in aquatic environments. Upon appropriate regulation, the remarkable removal efficiency of SMTZ was observed in a UV/MgO2 system, and the pseudo-first-order reaction constant reached 0.4074 min-1. In addition, the better performance of the UV/MgO2 system in a weak acid environment was discovered. During the removal of SMTZ, the pathways of SMTZ degradation were deduced, including nitration, ring opening, and group loss. In the mineralization exploration, the further removal of residual products of SMTZ by the UV/MgO2 system was visually demonstrated. The qualitative and quantitative researches as well as the roles of reactive species were valuated, which revealed the important role of ·O2-. Common co-existing substances in actual wastewater such as NO3- HA, Cl-, Fe2+, Co2+, and Mn2+ can slightly inhibit the degradation of SMTZ in the UV/MgO2 system. Finally, the capacity of efficient degradation of SMTZ in actual wastewater by the UV/MgO2 system was proved. The results indicated that the innovative UV/MgO2 system was of great practical application prospect in antibiotic residue wastewater remediation.
Subject(s)
Water Pollutants, Chemical , Water Purification , Anti-Bacterial Agents/chemistry , Magnesium Oxide , Wastewater , Hydrogen Peroxide/chemistry , Water Pollutants, Chemical/chemistry , Ultraviolet Rays , Sulfamethazine/chemistry , Sulfanilamide , Oxidation-Reduction , Kinetics , Sulfonamides , Water Purification/methodsABSTRACT
In the present work, a cobalt-doped carbon nitride nanotubes (Co-CNt) was synthesized via self-assembly process. Contributed to the narrow band gap, enlarged specific surface area and abundant active sites, Co-CNt has excellent photoelectric properties and superior performance than pristine CN in sulfisoxazole (SIZ) degradation under blue light irradiation, which achieved 100% removal within 40 min. Meanwhile, the system not only exhibited practical applicability by efficiently degrading SIZ, but also generating high levels of H2O2. Moreover, the Co-CNt/visible light system shows superior operability over a wide pH range, micro-concentration contaminants, various anions, water matrices and other sulfonamides with promising catalytic stability and applicability. The contribution of RSs in the degradation process were elucidated based on radical scavenging and spin-trapped tests, clarifying that O2·- and h+ majorly dominated the process. In addition, 4 probable degradation pathways of SIZ were provided and the generated intermediates' toxicity were evaluated. Overall, this study successfully synthesized a self-assembled 1D tubular photocatalyst with Co-doped and demonstrated the potential Co-CNt/visible light system for environmental remediation, providing a promising approach for the development of photocatalysis.
Subject(s)
Anti-Bacterial Agents , Nanotubes , Hydrogen Peroxide , Sulfanilamide , Sulfisoxazole , CatalysisABSTRACT
The widespread use of sulfonamides (SAs) in animals and human infections has raised significant concerns regarding their presence in ambient waterways and potential for inducing antimicrobial resistance. Herein, we report on the capacity of ferrate (VI) (FeVIO42-, Fe(VI)) to facilitate the photocatalytic degradation of sulfamethazine (SMT) via bismuth tungstate (Bi2WO6, BWO) under blue LED light (Vis/BWO/Fe(VI)) exposure, at rates that were 45-fold faster than BWO photocatalysis. Both the stepwise and time-series addition of Fe(VI) contributed to the degradation. Multiple lines of evidence confirmed that the common reactive species (RSs) in BWO-based photocatalytic systems and Fe(VI)-involved systems (e.g., â¢OH/h+, O2â¢-, 1O2 and Fe(V)/Fe(IV)) played subtle roles in our study system. Herein, for the first time, it was discovered that the precursor complex (BWO-Fe(V)/Fe(IV)* )) was the main contributor to induce electron transfer of SAs through the "conductive bridge" effect of BWO. The studied system was able to effectively degrade SMT in synthetic hydrolyzed urine (SHU) with low interference from background substances in water. This work not only offers a novel facilitation strategy for BWO, but also holds a great application prospect for contamination remediation in urine.
Subject(s)
Electrons , Sulfonamides , Humans , Oxidation-Reduction , Electron Transport , LightABSTRACT
OBJECTIVES: To study the etiology and clinical features of children with ascites, so as to provide a basis for the diagnosis and treatment of ascites in children. METHODS: The medical data of the children with ascites, who were hospitalized from January 1, 2010 to December 31, 2019, were retrospectively reviewed. RESULTS: Among the 165 children with ascites, the male/female ratio was 1.53:1, and the mean age of onset was (6±4) years. The causes of ascites included surgical acute abdomen (39 children, 23.6%), infectious diseases (39 children, 23.6%), neoplastic diseases (27 children, 16.4%), hepatogenic diseases (18 children, 10.9%), pancreatitis (10 children, 6.1%), cardiogenic diseases (8 children, 4.8%), rheumatic immune diseases (6 children, 3.6%), and nephrogenic diseases (5 children, 3.0%). According to the age of onset, there were 33 infants, 24 young children, 30 preschool children, 41 school-aged children, and 37 adolescents. Surgical acute abdomen and hepatogenic diseases were the main causes of ascites in infants (P<0.05). Neoplastic disease was the leading cause in young children (P<0.05). Infectious diseases were the most common cause in adolescents (P<0.05). CONCLUSIONS: Surgical acute abdomen, infectious diseases, neoplastic diseases, and hepatogenic diseases are the common causes of ascites in children, and there are some differences in the leading cause of ascites between different age groups.
Subject(s)
Abdomen, Acute , Communicable Diseases , Neoplasms , Pancreatitis , Abdomen, Acute/complications , Adolescent , Ascites/etiology , Child , Child, Preschool , Female , Humans , Infant , Male , Neoplasms/complications , Pancreatitis/complications , Retrospective StudiesABSTRACT
Lead pollution has become a global concern due to its ubiquity and persistence. This study describes two FeMn oxide substrate adsorbents, namely, FeMn binary oxides (FMBO) and mesoporous FeMn binary oxide (MFMBO) covered with tannic acid film (FMBO@TA-Fe3+ and MFMBO@TA-Fe3+), for the treatment of Pb2+ in water. The characterization results showed that TA was successfully coated onto the surfaces of FMBO and MFMBO. The maximum capacities of Pb2+ on FMBO@TA-Fe3+ and MFMBO@TA-Fe3+ were 322.08 and 357.14 mg g-1, respectively, which were twice those of FMBO and MFMBO. The adsorption of Pb2+ on the adsorbents was a spontaneous, endothermic process with increasing disorder through thermodynamics studies. An overall mechanism was proposed for Pb2+ adsorption, the improved adsorption performance of FMBO@TA-Fe3+ and MFMBO@TA-Fe3+ is ascribed to the mesoporous characteristics and the introduction of hydroxyl groups. Further investigation indicated the adsorption of Pb2+ could be attributed to electrostatic interactions on FMBO@TA-Fe3+ and MFMBO@TA-Fe3+, and cation exchange existed through the formation of these internal surface complexes. The Pb2+-loaded adsorbents could be effectively desorbed in a dilute hydrochloric acid solution, promoting recycling and reuse of the regenerated adsorbents. These results warrant the promising application of FMBO@TA-Fe3+ and MFMBO@TA-Fe3+ for the removal of Pb2+, and this work first proposed TA film-modified FMBO and MFMBO to improve its adsorption capacity in the application of environmental remediation.
ABSTRACT
In this study, the objective was mainly focusing on the mechanism investigation of ciprofloxacin (CIP) degradation by photocatalytic ozonation process which carried out by ozone and TiO2 with a low content of carbon-dots (CDs) under simulated sunlight irradiation. The physicochemical properties of the prepared photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) X-ray photoelectron spectroscopy (XPS) and zeta potential. Comprehensive investigation has proven the process to be efficient in the removal of CIP with high yield of reactive species (OH, O2-, h+, etc.). Kinetic model on pH investigation found out a repulsive force between the photocatalysts and CIP intensified with the increasing pH, so did the production rate of hydroxyl radicals (OH), while eventually reached a balance and achieved a maximum degradation rate. The results indicated that the enhancement mechanism was triggered by the photoexcited electron accumulated on CDs and transferred by ozone, resulting in the continuous generation of h+, O3- and O2-. Possible photocatalytic ozonation degradation pathways of CIP were proposed according to the identifications of intermediates using high-resolution accurate-mass spectrometry (HRAM) LC-MS/MS.
Subject(s)
Ciprofloxacin/chemistry , Environmental Restoration and Remediation , Free Radicals/chemistry , Ozone/chemistry , Quantum Dots/chemistry , Sunlight , Anti-Bacterial Agents/chemistry , Carbon/chemistry , Catalysis , Kinetics , Titanium/chemistry , Water Pollutants, Chemical/chemistryABSTRACT
OBJECTIVE: To investigate the prevalence of cagA, vacA, and iceA genotypes in the isolated strains of Helicobacter pylori (H.pylori) from children with gastroduodenal diseases in Jiangxi, China, as well as the association between cagA, vacA, and iceA genotypes and the type of gastroduodenal diseases. METHODS: The samples of gastric antral mucosa were collected from 316 children with gastroduodenal diseases in Jiangxi, and a total of 107 strains of H.pylori were isolated. The genomic DNA of these strains was extracted, and PCR was used to determine the ureA, cagA, vacA, and iceA genotypes. RESULTS: Of all the 107 isolated strains of H.pylori, the detection rates of ureA and cagA genes were 100% (107/107) and 94.4% (101/107) respectively. The overall detection rate of vacA gene was 100% (107/107), and the detection rates of vacAs1a, vacAs1c, vacAm1, and vacAm2 genes were 74.8% (80/107), 25.2% (27/107), 29.9% (32/107), and 69.2% (74/107) respectively, with both vacAm1 and vacAm2 genes detected in 0.9% (1/107) of all H.pylori strains. In the chimera of vacA gene, the detection rates of vacAs1a/m1, vacAs1a/m2, vacAs1c/m1, and vacAs1c/m2 genes were 26.2% (28/107), 51.4% (55/107), 3.7% (4/107), and 17.8% (19/107) respectively (P<0.001). The detection rates of iceA1 and iceA2 genes were 79.4% (85/107) and 9.3% (10/107), respectively (P<0.001), and both iceA1 and iceA2 genes were detected in 7.5% (8/107) of all strains. The detection rates of the genotypes of H.pylori showed no significant differences between the peptic ulcer, chronic gastritis, and duodenal bulbar inflammation groups (P>0.05). CONCLUSIONS: The dominant genotypes of H.pylori are cagA, vacAs1a/m2, and iceA1, and there are mixed infections with H.pylori strains of different genotypes in children with gastroduodenal disease from Jiangxi, China. The genotypes of H.pylori are not associated with the type of gastroduodenal disease.