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1.
BMC Med Imaging ; 23(1): 173, 2023 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-37907837

RESUMO

PURPOSE: To investigate the prognosis value of a combined model based on 18F-fluoro-deoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) baseline and interim parameters in patients with diffuse large B-cell lymphoma (DLBCL). METHODS: We retrospectively analyzed the PET metabolic parameters and clinical data of 154 DLBCL patients between December 2015 and October 2020. All of these patients underwent 18F-FDG PET/CT scan before treatment and after three or four courses of chemotherapy. The optimal cut-off values for quantitative variables were determined by the receiver operating characteristic (ROC) curve. The baseline and interim PET/CT parameters, which respectively included maximum standardized uptake value (SUVmax0), total metabolic tumor volume (TMTV0), standardized total metabolic tumor volume (STMTV0), and the distance between the two furthest lesions (Dmax) and total tumor lesion glycolysis (TTLG1), SUVmax1, TMTV1, and the rate of change of SUVmax (%ΔSUVmax), and clinical characteristics were analyzed by chi-squared test, Kaplan-Meier survival curve, and Cox regression analysis. RESULTS: Of 154 patients, 35 exhibited disease progression or recurrence. ROC analysis revealed that baseline 18F-FDG PET/CT metabolic parameters, including maximum standardized uptake value (SUVmax0), total metabolic tumor volume (TMTV0), standardized total metabolic tumor volume (STMTV0), and the distance between the two furthest lesions (Dmax), along with interim 18F-FDG PET/CT metabolic parameters such as total tumor lesion glycolysis (TTLG1), SUVmax1, TMTV1, and the rate of change of SUVmax (%ΔSUVmax), were predictive of relapse or progression in DLBCL patients (P < 0.05). The chi-squared test showed that TMTV0, STMTV0, Dmax, SUVmax1, TMTV1, TTLG1, %ΔSUVmax, Deauville score, IPI, Ann Arbor stage, and LDH were associated with patient prognosis (P < 0.05). Multivariate Cox regression analysis showed that Dmax (P = 0.021) and %ΔSUVmax (P = 0.030) were independent predictors of prognosis in DLBCL patients. There were statistically significant differences in PFS among the three groups with high, intermediate, and low risk according to the combination model (P < 0.001). The combination model presented higher predictive efficacy than single indicators. CONCLUSION: The combined model of baseline parameter Dmax and intermediate parameter %ΔSUVmax of 18F-FDG PET/CT improved the predictive efficacy of PFS and contributed to the risk stratification of patients, providing a reference for clinical individualization and precision treatment.


Assuntos
Linfoma Difuso de Grandes Células B , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Humanos , Fluordesoxiglucose F18 , Estudos Retrospectivos , Recidiva Local de Neoplasia , Tomografia por Emissão de Pósitrons , Prognóstico , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Linfoma Difuso de Grandes Células B/tratamento farmacológico
2.
BMC Med Imaging ; 22(1): 226, 2022 12 24.
Artigo em Inglês | MEDLINE | ID: mdl-36566187

RESUMO

BACKGROUND: We aimed to determine the performance of 18 F-FAPI PET/CT used for preprocedural assessment of glioblastoma before radiotherapy. METHODS: Twelve glioblastoma patients having undergone incomplete surgical resection or biopsy were examined with 18 F-FAPI PET/CT and MRI scanning before radiotherapy. All patients had confirmed tumor residues according to findings of histopathological and/or long-term clinical and radiological follow-ups. Lesion characterization data, including SUVmax and tumor-to-background ratio (TBR) on PET/CT were attained. PET/CT and MRI findings were compared in terms of number of lesions. The correlation between immunohistochemistry, molecular expression, and PET/CT parameters was also evaluated. RESULTS: 18 F-FAPI PET/CT detected 16 FAPI-avid out of 23 lesions in 12 patients described on MRI. MRI was statistically different from 18 F-FAPI PET/CT for lesion detection according to the exact McNemar statistical test (P = 0.0156). The SUVmax and TBR of the glioblastomas was 7.08 ± 3.55 and 19.95 ± 13.22, respectively. The sensitivity and positive predictive value (PPV) of 18 F-FAPI PET were 69.6% and 100%, respectively. Neither the Ki-67 index nor the molecular expression was correlated with the FAPI-PET/CT parameters. CONCLUSION: 18 F-FAPI PET/CT detects glioblastomas at a lower rate than MRI. However, the 100% PPV of the examination may make it useful for differentiating controversial lesions detected on MRI. The 18 F-FAPI-avid lesions are displayed more clearly probably due to a higher TBR. 18 F-FAPI PET/CT imaging might find application in glioblastoma biopsy and radiotherapy planning.


Assuntos
Glioblastoma , Radiologia , Humanos , Glioblastoma/diagnóstico por imagem , Glioblastoma/radioterapia , Projetos Piloto , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Biópsia , Fluordesoxiglucose F18
3.
J Environ Manage ; 317: 115437, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35661878

RESUMO

Biochar can achieve multiple benefits including solid waste management, polluted water remediation, carbon sequestration, and emission reduction. However, various environmental factors (such as temperature variations and dry-wet alternation) and microbial activity may lead to the fragmentation, dissolution, and oxidation of biochar. These accelerate the dissolution of biochar-derived dissolved organic matter (DOM) and then influence disinfection byproducts formation potential (DBPFP) throughout the water treatment process. In this paper, biochars from six biomass feedstocks with five aging processes were prepared, and the DBPFP of biochar and its derived DOM were first studied systematically. Different aging processes might increase the DBPFP of biochar by increasing DOM content and changing the fraction distribution of DOM derived from biochar. Especially, the DBPFP of biochar increased apparently with the chemical aging process. Coexisting with the environmental concentration of humic acid, even aged biochar showed the potential to reduce DBPFP and integrated toxic risk value of the mixed system. In this study, the DBPFP of biochar-derived DOM during the disinfection process is confirmed, and the results can give information to the selection of biomass feedstocks of biochar and its service life in the water treatment process.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Carvão Vegetal/química , Desinfecção/métodos , Matéria Orgânica Dissolvida , Halogenação , Poluentes Químicos da Água/química
4.
J Environ Sci (China) ; 87: 10-23, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791484

RESUMO

Five biochars derived from lotus seedpod (LSP) were applied to examine and compare the adsorption capacity of 17ß-estradiol (E2) from aqueous solution. The effect of KOH activation and the order of activation steps on material properties were discussed. The effect of contact time, initial concentration, pH, ionic strength and humic acid on E2 adsorption were investigated in a batch adsorption process. Experimental results demonstrated that the pseudo second-order model fitted the experimental data best and that adsorption equilibrium was reached within 20 hr. The efficiency of E2 removal increased with increasing E2 concentration and decreased with the increase of ionic strength. E2 adsorption on LSP-derived biochar (BCs) was influenced little by humic acid, and slightly affected by the solution pH when its value ranged from 4.0 to 9.0, but considerably affected at pH 10.0. Low environmental temperature is favorable for E2 adsorption. Chemisorption, π-π interactions, monolayer adsorption and electrostatic interaction are the possible adsorption mechanisms. Comparative studies indicated that KOH activation and the order of activation steps had significant impacts on the material. Post-treated biochar exhibited better adsorption capacity for E2 than direct treated, pre-treated, and raw LSP biochar. Pyrolyzed biochar at higher temperature improved E2 removal. The excellent performance of BCs in removing E2 suggested that BCs have potential in E2 treatment and that the biochar directly treated by KOH would be a good choice for the treatment of E2 in aqueous solution, with its advantages of good efficiency and simple technology.


Assuntos
Estradiol/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Carvão Vegetal , Temperatura Alta , Substâncias Húmicas , Concentração de Íons de Hidrogênio , Hidróxidos , Cinética , Lotus , Concentração Osmolar , Compostos de Potássio , Sementes , Temperatura
5.
Crit Rev Biotechnol ; 39(5): 746-757, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30955366

RESUMO

The objective of this study is to summarize the effects of surfactants on anaerobic digestion (AD) of waste activated sludge (WAS). The increasing amount of WAS has caused serious environmental problems. Anaerobic digestion, as the main treatment for WAS containing three stages (i.e. hydrolysis, acidogenesis, and methanogenesis), has been widely investigated. Surfactant addition has been demonstrated to improve the efficiency of AD. Surfactant, as an amphipathic substance, can enhance the efficiency of hydrolysis by separating large sludge and releasing the encapsulated hydrolase, providing more substance for subsequent acidogenesis. Afterwards, the short chain fatty acids (SCFAs), as the major product, have been produced. Previous investigations revealed that surfactant could affect the transformation of SCFA. They changed the types of acidification products by promoting changes in microbial activity and in the ratio of carbon to nitrogen (C/N), especially the ratio of acetic and propionic acid, which were applied for either the removal of nutrient or the production of polyhydroxyalkanoate (PHA). In addition, the activity of microorganisms can be affected by surfactant, which mainly leads to the activity changes of methanogens. Besides, the solubilization of surfactant will promote the solubility of contaminants in sludge, such as organic contaminants and heavy metals, by increasing the bioavailability or desorbing of the sludge.


Assuntos
Ácidos Graxos/metabolismo , Metano/metabolismo , Esgotos , Tensoativos/farmacologia , Eliminação de Resíduos Líquidos/métodos , Anaerobiose/efeitos dos fármacos , Poluição da Água
6.
Environ Sci Technol ; 51(11): 6352-6359, 2017 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-28494154

RESUMO

Adsorption of two estrogen contaminants (17ß-estradiol and 17α-ethynyl estradiol) by graphene nanomaterials was investigated and compared to those of a multi-walled carbon nanotube (MWCNT), a single-walled carbon nanotube (SWCNT), two biochars, a powdered activated carbon (PAC), and a granular activate carbon (GAC) in ultrapure water and in the competition of natural organic matter (NOM). Graphene nanomaterials showed comparable or better adsorption ability than carbon nanotubes (CNTs), biochars (BCs), and activated carbon (ACs) under NOM preloading. The competition of NOM decreased the estrogen adsorption by all adsorbents. However, the impact of NOM on the estrogen adsorption was smaller on graphenes than CNTs, BCs, and ACs. Moreover, the hydrophobicity of estrogens also affected the uptake of estrogens. These results suggested that graphene nanomaterials could be used to removal estrogen contaminants from water as an alternative adsorbent. Nevertheless, if transferred to the environment, they would also adsorb estrogen contaminants, leading to great environmental hazards.


Assuntos
Estrogênios , Nanoestruturas , Poluentes Químicos da Água , Adsorção , Carbono , Carvão Vegetal , Grafite , Nanotubos de Carbono , Purificação da Água
7.
J Environ Manage ; 184(Pt 1): 85-93, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27591848

RESUMO

A novel biochar/MgAl-layered double hydroxides composite (CB-LDH) was prepared for the removal of crystal violet from aqueous solution by pyrolyzing MgAl-LDH pre-coated ramie stem (Boehmeria nivea (L.) Gaud.). Pyrolysis played dual role for both converting biomass into biochar and calcining MgAl-LDH during the pyrolysis process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and zeta potential analysis were used to characterize the CB-LDH. The results of characterization suggested that the calcined LDH was successfully synthesized and coated on biochar. The resulted CB-LDH had higher total pore volume and more functional groups than the pristine biochar. Adsorption experimental data fitted well with the pseudo-second order kinetics model and the Freundlich isotherm model. The rate-controlled step was controlled by film-diffusion initially and then followed by intra-particle diffusion. Thermodynamic analysis showed that the adsorption of crystal violet was a spontaneous and endothermic process. The higher pH and temperature of the solution enhanced the adsorption performance. CB-LDH could also have excellent ability for the removal of crystal violet from the actual industrial wastewater and groundwater with high ionic strength. LDH adsorption, electrostatic attraction, pore-filling, π-π interaction and hydrogen bond might be the main mechanisms for crystal violet adsorption on CB-LDH. The results of this study indicated that CB-LDH is a sustainable and green adsorbent with high performance for crystal violet contaminated wastewater treatment and groundwater remediation.


Assuntos
Boehmeria/química , Carvão Vegetal/química , Violeta Genciana/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Hidróxido de Alumínio/química , Biomassa , Água Subterrânea/química , Concentração de Íons de Hidrogênio , Cinética , Hidróxido de Magnésio/química , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Soluções , Temperatura , Termodinâmica , Águas Residuárias/química
8.
J Environ Sci (China) ; 43: 40-47, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27155407

RESUMO

Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to 314.2µg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S. trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects.


Assuntos
Proliferação Nociva de Algas/efeitos dos fármacos , Microcystis/efeitos dos fármacos , Extratos Vegetais/toxicidade , Sagittaria , Clorofila , Clorofila A , Cianobactérias , Glutationa/metabolismo , Peroxidação de Lipídeos , Malondialdeído/metabolismo , Estresse Oxidativo , Oxirredutases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
9.
J Environ Manage ; 153: 68-73, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25660498

RESUMO

This study investigated the efficiency and mechanisms of Cd removal by biochar pyrolyzed from water hyacinth (BC) at 250-550 °C. BC450 out-performed the other BCs at varying Cd concentrations and can remove nearly 100% Cd from aqueous solution within 1 h at initial Cd ≤ 50 mg l(-1). The process of Cd sorption by BC450 followed the pseudo-second order kinetics with the equilibrium being achieved after 24 h with initial Cd ranging from 100 to 500 mg l(-1). The maximum Cd sorption capacity of BC450 was estimated to be 70.3 mg g(-1) based on Langmuir model, which is prominent among a range of low-cost sorbents. Based on the balance analysis between cations released and Cd sorbed onto BC450 in combination with SEM-EDX and XPS data, ion-exchange followed by surface complexation is proposed as the dominant mechanism responsible for Cd immobilization by BC450. In parallel, XRD analysis also suggested the formation of insoluble Cd minerals (CdCO3, Cd3P2, Cd3(PO4)2 and K4CdCl6) from either (co)-precipitation or ion exchange. Results from this study highlighted that the conversion of water hyacinth into biochar is a promising method to achieve effective Cd immobilization and improved management of this highly problematic invasive species.


Assuntos
Cádmio/química , Carvão Vegetal/química , Eichhornia/química , Poluentes Químicos da Água/química , Adsorção , Troca Iônica
10.
Artigo em Inglês | MEDLINE | ID: mdl-38913263

RESUMO

Micro-nanobubbles (MNBs) can form reactive oxygen species (ROS) with high oxidizing potential. In this study, nickel-doped metal-organic framework materials (MOFs) capable of activating molecular oxygen were synthesized using trivalent arsenic (As(III)) as a target pollutant and combined with peroxymonosulfate (PMS) to construct a MOF/MNB/PMS system. The results included the rapid oxidation of As(III), the successful absorption of oxidized As(V), and finally the efficient removal of As. The effects of pH, amount of PMS used, and preparation time of MNBs on the As removal performance of the MOF/MNB/PMS system were investigated experimentally. The changes in the properties of the materials before and after the reaction were analyzed by XPS, and it was found that the main active sites on the surface of the MOFs were the metal elements and the pyridine nitrogen near the carbon atom. The regular morphology and elemental composition of the MOFs were determined by TEM scanning and EDS test, which indicated the presence of nickel. XRD tests before and after the reaction showed that the MOFs were structurally stable. The results of the free radical burst experiments show that the single linear oxygen (1O2) is the main active substance in the system, and that the MNBs are key factors by which the system achieves efficient oxidation performance. In addition to providing a sustainable supply of molecular oxygen to the MOFs during the reaction process, coupling the MNBs with PMS was found to improve the oxidation capacity of the system. The results of this study thus provide a new concept for As removal and advanced oxidation in water bodies.

11.
Sci Total Environ ; 923: 171350, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38432377

RESUMO

Microplastics (MPs) pollution is widely investigated owing to its potential threats to river ecosystems. However, it remains unclear whether hydraulic disturbance deepens or mitigates the effects of MPs-contaminated sediments on the river environment. Herein, we studied the impact of sediment aggregates, organic matter, and enzyme activity, with emphasis on microbial community structure and function in sediments exposed to MPs (1 %, 5 %, and 10 % w/w) in conjunction with hydraulic disturbance. The experimental results showed that the influence of MPs on the sediment under hydraulic disturbance is more significant than that of static culture, especially for various environmental factors (MWD, MBC, and sucrase activity etc.). The proportions of the >0.05 mm-fraction aggregates increased from 74-76 % to 82-88 % in the sediment throughout the entire disturbance process. It has been found that the disturbance generally promotes the interaction between MPs and sediments. FAPROTAX analysis demonstrated that the disturbance reduced the difference in effects on microbial functional genes between the control group and the MPs-added groups by up to 10 times, suggesting that the effects of disturbance on MPs-contaminated sediments are relatively complex. This work provides new insights into the effects of hydraulic disturbance on physicochemical properties and microbial communities of MPs-contaminated sediment.


Assuntos
Microbiota , Poluentes Químicos da Água , Microplásticos , Plásticos , Poluição Ambiental , Rios , Sedimentos Geológicos , Monitoramento Ambiental
12.
Environ Pollut ; 346: 123641, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38428791

RESUMO

The excessive accumulation of hexavalent chromium (Cr(VI)) in the environment poses a risk to environment and human health. In the present study, a potassium bicarbonate-modified pyrite/porous biochar composite (PKBC) was prepared in a one-step process and applied for the efficient removal of Cr(VI) in wastewater. The results showed that PKBC can significantly remove Cr(VI) within 4 h over a wide range of pH (2-11). Meanwhile, the PKBC demonstrated remarkable resistance towards interference from complex ions. The addition of potassium bicarbonate increased the pore structure of the material and promoted the release of Fe2+. The reduction of Cr(VI) in aqueous solution was primarily attributed to the Fe(II)/Fe(III) redox cycle. The sulphur species achieved Fe(II)/Fe(III) cycle through electron transfer with iron, thus ensuring the continuous reduction capacity of PKBC. Besides, the removal rate was also maintained at more than 85% in the actual water samples treatment process. This work provides a new way to remove hexavalent chromium from wastewater and demonstrates the potential critical role of potassium bicarbonate and sulphur.


Assuntos
Bicarbonatos , Compostos de Potássio , Sulfetos , Águas Residuárias , Poluentes Químicos da Água , Humanos , Compostos Férricos , Potássio , Porosidade , Ferro/química , Carvão Vegetal/química , Cromo/química , Compostos Ferrosos , Poluentes Químicos da Água/análise , Adsorção
13.
Chemosphere ; 345: 140436, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37838028

RESUMO

Residual flotation chemicals in beneficiation wastewater seriously threaten local ecosystems, such as groundwater or soil, and must be treated effectively. Currently, the degradation of organic pollutants using nitrided MOFs-derived carbon to activate persulfate (PDS) has attracted considerable attention. Hence, we developed a new synthetic strategy to load dopamine hydrochloride (PDA) onto MOF-5-derived porous carbon (PC) to form NPC, and the degradation of a typical flotation Aniline aerofloat (AAF) at high salinity by a low dose of the NPC/PDS system was investigated. Several characterization analyses such as TEM, XRD, Raman, FT-IR and XPS demonstrated that the nitrogen-rich indolequinone unit in PDA provided nitrogen to PC during the pyrolysis process. This enabled the core-shell structure of NPC and the synergy among the multiple components to induce the AAF degradation by PDS over a wide pH scale in a short period of time. It was deduced that the degradation of AAF by the NPC-8/PDS system was a non-radical pathway dominated by 1O2, which relied mainly on the conversion of superoxide radicals (O2•-) and surface-bound radicals. Among them, the pyridine N in the sp2 hybrid carbon was considered as a possible active site. This non-radical pathway was resistant to pH changes and background substances in the water, and well overcame the inhibition of the reaction by natural organic substances and inorganic anions in natural water. In this study, A novel approach to the synthesis of homogeneous MOFs nuclear-derived porous carbon was proposed and the application of MOFs-derived porous carbon for AAF remediation of mineral processing wastewater was broadened.


Assuntos
Carbono , Águas Residuárias , Carbono/química , Ecossistema , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos de Anilina , Água , Nitrogênio
14.
Water Res ; 245: 120614, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37717327

RESUMO

Catalysts for peroxymonosulfate (PMS) activation are appealing in the purification of organic wastewater. Singlet oxygen (1O2) is widely recognized as a crucial reactive species for degrading organic contaminants in catalysts/PMS systems due to its adamant resistance to inorganic anions, high selectivity, and broad pH applicability. With the rapid growth of studies on 1O2 in catalysts/PMS systems, it becomes necessary to provide a comprehensive review of its current state. This review highlights recent advancements concerning 1O2 in catalysts/PMS systems, with a primary focus on generation pathways and identification methods. The generation pathways of 1O2 are summarized based on whether (distinguished by the geometric structures of metal species) or not (distinguished by the active sites) the metal element is included in the catalysts. Furthermore, this review thoroughly discusses the influence of metal valence states and metal species with different geometric structures on 1O2 generation. Various potential strategies are explored to regulate the generation of 1O2 from the perspective of catalyst design. Identification methods of 1O2 primarily include electron paramagnetic resonance (EPR), quenching experiments, reaction in D2O solution, and chemical probe tests in catalysts/PMS systems. The principles and applications of these methods are presented comprehensively along with their applicability, possible disagreements, and corresponding solutions. Besides, an identifying procedure on the combination of main identification methods is provided to evaluate the role of 1O2 in catalysts/PMS systems. Lastly, several perspectives for further studies are proposed to facilitate developments of 1O2 in catalysts/PMS systems.

15.
Sci Total Environ ; 895: 165171, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37379931

RESUMO

The frequent occurrence of algal blooms in water bodies leads to a significant accumulation of microcystin-LR (MC-LR). In this study, we developed a porous foam-like self-floating N-deficient g-C3N4 (SFGN) photocatalyst for efficient photocatalytic degradation of MC-LR. Both the characterization results and DFT calculations indicate that the surface defects and floating state of SFGN synergistically enhance light harvesting and photogenerated carrier migration rate. The photocatalytic process achieved a nearly 100 % removal rate of MC-LR within 90 min, while the self-floating state of SFGN maintained good mechanical strength. ESR and radical capture experiments revealed that the primary active species responsible for the photocatalytic process was OH. This finding confirmed that the fragmentation of MC-LR occurs as a result of OH attacking the MC-LR ring. LC-MS analysis indicated that majority of the MC-LR molecules were mineralized into small molecules, allowing us to infer possible degradation pathways. Furthermore, after four consecutive cycles, SFGN exhibited remarkable reusability and stability, highlighting the potential of floating photocatalysis as a promising technique for MC-LR degradation.


Assuntos
Luz , Microcistinas , Fotólise , Catálise
16.
J Hazard Mater ; 455: 131589, 2023 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-37163890

RESUMO

Although water metalloid pollution is widely studied, the effect of the combined pollution of organic matter and metalloids in mining water and, especially, the possible interaction mechanisms between metalloids and flotation reagents, are both poorly understood. Existence of mixed pollution of metalloids and organic compounds tends to cause more serious harm to natural organisms. In this study, a synergistic removal of arsenite (As(III)) and butyl xanthate (Bx) in an advanced oxidation system was reported using biochar-based catalyst loaded with nano-zero-valent iron from an inexpensive iron source (iron slag) to activate peroxodisulfate. The removal efficiencies were improved by 30 % in the co-existence of As(III) and Bx compared to those of the single pollutant. The theoretical calculations, especially frontier molecular orbital theory, revealed the generation of [AsO2-OH]•- by the combination of As(II) with •OH. This [AsO2-OH]•- participated in the oxidative degradation of Bx with high activity and combined with the sulfur falling off Bx after the reaction to form a novel Fe-As-S complex as indicated by X-ray absorption +fine structure analysis. Overall, this study reports the generation of low-valent arsenic active substances of [AsO2-OH]•- and their effect on the removal of organic pollution containing S atoms in advanced oxidation systems under typical mining water conditions with the coexistence of As(III) and expands the understanding and application of traditional free radicals.

17.
Water Res ; 231: 119659, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36716570

RESUMO

Residual flotation reagents in mineral processing wastewater can trigger severe ecological threats to the local groundwater if they are discharged without treatment. Metal-free biochar-induced persulfate-advanced oxidation processes (KCBC/PS) were used in this study to elucidate the degradation of aniline aerofloat (AAF) - a typical flotation reagent. In KCBC/PS system, AAF can be removed at low doses of catalyst (KCBC, 0.05 g/L) and oxidant (PS, 0.3 mM) additions with high efficiency. The analysis revealed the dominance of O2•- among the identified reactive oxygen species (ROS), which achieved deeper mineralization for the AAF degradation in the KCBC/PS system. The role of the electron transfer mechanism was equally important; the importance was corroborated by the chemical quenching experiments, electron spin resonance (ESR) detection, probe experiments, and electrochemical analysis. It benefited from the electron transfer mechanism in the KCBC/PS system and exhibited a wide pH adaptation (3.5-11) and high resistance to inorganic anions for real mining wastewater treatment. Combined with theoretical calculations and other analyses, the carbonyl group was deemed to be the active site of the non-radical pathway of biochar, while the site of the conversion of SO4•- to superoxide radicals by biochar activation represented a defect. These findings revealed a synergistic effect of multiple active sites on PS activation in biochar-based materials. Moreover, the intermediate degradation products of AAF from mass spectrometry indicated a possible pathway through the density functional theory (DFT) method, which was effective in reducing the environmental toxicity of pollutants for the first time according to the T.E.S.T software and seed germination experiments. Overall, our study proposed a novel modification strategy for cost-effective and environmentally friendly biochar-based catalysts, while also deepening our understanding of the mechanism of activation of persulfate by metal-free carbon-based materials.


Assuntos
Elétrons , Poluentes Químicos da Água , Carvão Vegetal/química , Transporte de Elétrons , Oxirredução , Metais , Compostos de Anilina , Poluentes Químicos da Água/química
18.
Front Med (Lausanne) ; 10: 1238333, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37727766

RESUMO

18F-PSMA-1007 PET/CT imaging is increasingly used for the diagnosis, staging, and efficacy assessment of patients with prostate cancer. Compared with other PSMA tracers, 18F-PSMA-1007 is mainly cleared by the liver and bile and has lower urinary clearance, thus allowing a better assessment of the lesions around the bladder. However, there were some patients who showed an obvious concentration of the 18F-PSMA-1007 in the bladder, which may affect the observation of peripheral lesions, but the mechanism of this change is unknown. The aim of this study was to explore the cause of bladder 18F-PSMA-1007 concentration by assessing the clinical and imaging characteristics of 18F-PSMA-1007 PET/CT scans. A total of 284 patients were included in this retrospective study, and their clinical characteristics such as age, height, weight, Gleason score, metastases, different treatment methods, the level of liver and kidney function, PSA level, and imaging characteristics such as 18F-PSMA-1007 injected activity, the interval between injection to scan, physiological distribution (parotid gland, kidney, liver, spleen, intestine, obturator internus), pathological distribution (prostate lesions, metastases) were collected, and were compared after subgrouping using bladder urine SUVmax. This study showed that the distribution of bladder 18F-PSMA-1007 was not correlated with the above clinical and imaging characteristics, so further studies are needed to find the explanations, and thus to improve the disease assessment of this type of prostate cancer patients.

19.
Sci Total Environ ; 844: 156924, 2022 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-35779737

RESUMO

Arsenic is one of the most common and harmful pollutants in environment throughout the world, especially in aqueous solutions. In this study, two kinds of industrial solid wastes (Oxide scale (OS) and Blast furnace slag (BFS)) and one kind of phytoremediation plant waste (Ramie stalk) were used to prepare an environmentally friendly, low-cost, and efficient calcium silicate coated nano zero-valent iron (nZVI)/biochar composite (BOS) for As(V) adsorption. The potential environmental risks of BOS and their effects on removal of arsenic ions from aqueous media were investigated. The adsorption mechanism was explored and discussed based on XRD, SEM-EDS, XPS, etc. The results suggested that the environmental risk and heavy metals toxicity in BOS by co-pyrolysis were significantly reduced compared to the original materials, and no additional contaminant was observed in the subsequent experiments. Simultaneously, the BOS showed excellent As(V) removal capacity (>99%) and regenerative properties. The As(V) removal mechanisms are mainly ascribed to the complexation and co-precipitation between Fe and As, and the hydrogen bond between CO functional group of BOS and As. The mechanism of enhanced nZVI activity for As(V) removal was revealed. A protective layer of Ca2SiO4 was formed on the surface of nZVI during the co-pyrolysis process to prevent the passivation of nZVI. During the reaction process, the Ca2SiO4 covering the nZVI surface would be continuously detached to expose the fresh surface of nZVI, thus providing more redox activity and adsorption sites. This study provides a new way to treat and recycle industrial steel solid wastes and phytoremediation plant wastes, and the produced calcium silicate coated-nZVI/biochar composite is proposed to be a very promising material for practical remediation of As(V)-contaminated water bodies.


Assuntos
Arsênio , Boehmeria , Poluentes Químicos da Água , Adsorção , Arsênio/análise , Biodegradação Ambiental , Compostos de Cálcio , Carvão Vegetal/química , Resíduos Industriais , Ferro/química , Medição de Risco , Silicatos , Resíduos Sólidos , Aço , Poluentes Químicos da Água/análise
20.
Water Res ; 225: 119191, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36215841

RESUMO

There are numerous studies concerning the impacts of widespread microplastic pollution on the ecological environment, and it shows synergistic effect of microplastics and co-exposed pollutants in risk enhancement. However, the control methods for removing harmful pollutants from microplastic surface to reduce their ecological toxicity has rarely been explored. In this paper, magnetic graphitized biochar as a catalyst is shown to achieve 97% removal of tetrabromobisphenol A (TBBPA) from microplastics by biochar mediated electron transfer. The changes in the surface and structure of microplastics caused by various aging processes affected the pollutant attachment and subsequent removal efficiency. After chlorination, the highest disinfection by-product (DBP) generation potential was observed by the group of microplastics attached with TBBPA. The oxidation system of biochar activating peroxodisulfate (PDS) can not only reduce the kinds of DBPs, but also greatly reduce the total amount of detected DBPs by 76%, as well as reducing the overall toxicity. This paper highlights an overlooked contribution of pollutant attachment to the potential risks of DBP generated from natural microplastics during chlorination process, and provides the underlying insights to guide the design of a biochar-based catalyst from wastes to achieve the removal of TBBPA from microplastics and reduce the risks and hazards of co-contamination.


Assuntos
Microplásticos , Poluentes Químicos da Água , Desinfecção , Plásticos , Poluentes Químicos da Água/análise
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