查找使用阿拉丁产品的科研文献

Photocatalytic Degradation of Sulfamethoxazole and Enrofloxacin in Water Using Electrospun Composite Photocatalytic Membrane

Xiaohu Lin,Haifeng Fang,Libing Wang,Danyan Sun,Gang Zhao,Jingcheng Xu

Photocatalysis has emerged as a promising technology for the removal of emerging contaminants such as antibiotics from water. Fixing photocatalytic materials on polymers to prepare applicable membranes is a feasible method for applying photocatalysis. This study explored the preparation of composite PAN-TiO2and PAN-TiO2-rGO (PAN-rGTi) photocatalytic membranes by combining TiO2, TiO2-reduced graphene oxide (rGO) and polyacrylonitrile (PAN) using electrospinning. Characterization through SEM and EDS analysis confirms the composite membrane’s microstructure and elemental composition. The electrospun PAN-TiO2and PAN-rGTi composite membranes exhibit a stable and efficient photocatalytic performance in degrading sulfamethoxazole (SMX) and enrofloxacin (ENR), two typical antibiotics commonly found in water bodies. Photocatalytic degradation experiments under simulated solar light reveal the superior performance of the composite photocatalytic membranes compared to PAN alone, with a notable increase in the reaction rate constants of PAN-TiO2(1.8 to 2.2 times for SMX and 3.2 to 4.0 times for ENR) and even higher enhancements for PAN-rGTi (2.8 to 3.0 times for SMX and 5.4 to 6.5 times for ENR) compared to PAN alone. Despite minor decreases (from 97.6% to 90.4%) in activity over five cycles, the photocatalytic composite membranes remain effective, showcasing their stability and recyclability. This study highlights the potential application of PAN-TiO2and PAN-rGTi composite membranes as sustainable and effective materials for removing emerging contaminants from water. Further exploration should focus on optimizing materials for specific emerging contaminants and improving their application feasibility for wastewater and water treatment and water purification in water bodies.

Removal of sulfamethoxazole by Fe(III)-activated peracetic acid combined with ascorbic acid

Yiqing Liu,Linghan Xu,Xin Li,Shixiang Wang

Ascorbic acid (AA) was used as a reducing agent to improve the Fe(III)-activated peracetic acid (PAA) system for the removal of sulfamethoxazole (SMX) in this work. The efficiency, influencing factors and mechanism of SMX elimination in the AA/Fe(III)/PAA process were studied. The results exhibited that AA facilitated the reduction of Fe(III) to Fe(II) and subsequently improved the activation of PAA and H2O2. Various radicals, including organic radicals (e.g. CH3C(O)O• and CH3C(O)OO•) and hydroxyl radical (HO•), were rapidly formed from the activated PAA and H2O2, resulting in SMX removal. Increasing dosages of PAA and Fe(III) contributed to enhanced SMX degradation, while excessive PAA and Fe(III) did not further promote SMX degradation. Due to the radicals' quenching effect, excess AA hindered SMX elimination in the AA/Fe(III)/PAA process. The presence of HCO3− and Cl− inhibited SMX removal in this system, whereas NO3−, SO42− and natural organic matter had little impact on SMX degradation. The transformation pathways of SMX in the AA/Fe(III)/PAA system included hydroxylation, bond cleavage and amino oxidation. This research provides a strategy to enhance the Fe(III)-activated PAA system for the elimination of refractory organic pollutants.

Improved sulfamethoxazole degradation by the addition of MoS2 into the Fe2+/peroxymonosulfate process

Songlin Wang,Wenxin Xu,Junfeng Wu,Qing Gong,Pengchao Xie

The low efficiency of transforming ferric ion (Fe 3+ ) to ferrous ion (Fe 2+ ) always challenges the activation of peroxymonosulfate (PMS) by (Fe 2+ ) processes in the degradation of micro-organic contaminants. In this study, molybdenum disulfide (MoS 2 ) which accelerated PMS activation and the Fe 2+ /Fe 3+ cycle through the reaction of Mo 4+ and Fe 3+ was employed to significantly improve the efficiency of Fe 2+ /PMS on sulfamethoxazole (SMX) degradation. Through the analysis of electron paramagnetic resonance (EPR) and quenching experiments, both sulfate and hydroxyl radicals have been proven to account for SMX degradation in the MoS 2 /Fe 2+ /PMS process. The optimal pH of 3 has been determined for SMX degradation in the process, and an equation to express the relationship between the rate of SMX degradation and the dosages of Fe 2+ , MoS 2 and PMS was simulated. Chloride ion and humic acid had positive and negative effects on the process, respectively, whereas nitrate and bicarbonate had no influences on SMX degradation. Through the identified intermediates by LC/MS, a transformation pathway of SMX in the MoS 2 /Fe 2+ /PMS process was proposed. Additionally, the good efficiency of SMX degradation (>80%) in real water matrices and good stability of MoS 2 after reuse for 6 times further suggest that the MoS 2 /Fe 2+ /PMS process can be effectively used to degrade SMX.

Theoretical insights into influence of additives on sulfamethoxazole crystal growth kinetics and mechanisms

Chen Qiao,Zhang Mingdong,Ji Yuanhui

In this work, the influence of the initial chemical potential gradient, stirring speed, and polymer type on sulfamethoxazole (SMX) crystal growth kinetics was systematically investigated through density functional theory (DFT) calculations, experimental measurements and the two-step chemical potential gradient model. To investigate the influence of different conditions on the thermodynamic driving force of SMX crystal growth, SMX solubilities in different polymer solutions were studied. Four model polymers effectively improved SMX solubility. It was further found that polyvinylpyrrolidone (PVP) and hydroxypropyl methyl cellulose (HPMC) played a crucial role in inhibiting SMX crystal growth. However, polyethylene glycol (PEG) promoted SMX crystal growth. The effect of the polymer on the crystal growth mechanisms of SMX was further analyzed by the two-step chemical potential gradient model. In the system containing PEG 6000, crystal growth is dominated by the surface reaction. However, in the system containing PEG 20000, crystal growth is dominated by both the surface reaction and diffusion. In addition, DFT calculations results showed that HPMC and PVP could form strong and stable binding energies with SMX, indicating that PVP and HPMC had the potential ability to inhibit SMX crystal growth.

Removal of sulfamethoxazole from water by biosurfactant-modified sludge biochar: Properties and mechanism

Tingbao Zhao,Amjad Ali,Junfeng Su,Shuyu Liu,Huan Yan,Liang Xu

With industrialization and urbanization accelerating, water pollution, especially from pharmaceuticals like sulfamethoxazole, has become a major global issue. The widespread use of sulfamethoxazole has increased its concentration in water bodies, posing serious threats to ecosystems and human health. Thus, developing efficient and cost-effective removal methods is urgently needed. The aim of this study was to synthesize and evaluate a biosurfactant modified sludge biochar to enhance its ability to remove sulfamethoxazole from wastewater. Sludge was used as raw material and modified sludge biochar was obtained by pyrolysis and biosurfactant modification. The effects of different pH, initial concentration of sulfamethoxazole and the amount of modified sludge biochar on sulfamethoxazole adsorption were investigated by batch adsorption experimental system and the adsorption mechanism was discussed. The modified biochar was characterized using techniques such as Fourier transform infrared spectroscopy. The maximum adsorption capacity of modified sludge biochar on sulfamethoxazole reached 43.61 mg/g. The biosurfactant modification significantly altered the pore structure and surface functional groups of the biochar, which improved the adsorption capacity of sulfamethoxazole. Both physisorption and chemisorption played an important role in the adsorption process. The results of this study provide a potential solution for the treatment of pollutants in water bodies.

Degradation of Sulfamethoxazole by Activation of Persulfate Based on Nitrogen-Doped Mesoporous Carbon

Zhang Kaibin,Liu Xiaocong,Wang Yi,Yang Guo,Zhu Ying,Jiang Caiyi,Pan Zhicheng,Liu Xiaonan,Xing Bo

In this study, novel nitrogen-doped mesoporous carbon was prepared using solvent evaporation self-assembly method and used to activate persulfate for sulfamethoxazole (SMZ) degradation. The physicochemical properties of the materials were characterized using a variety of characterization techniques (XRD, SEM, Raman, XPS, FTIR). SEM and BET results showed that the catalysts had an obvious pore structure and large specific surface area, which increased with the increase of nitrogen content. XPS results revealed that nitrogen doping could increase the content of graphite-N in mesoporous carbon (from 0.4 to 3.28%), which was the main reason for the excellent catalytic performance of the catalyst. SMZ (20 mg/L) could be effectively degraded by 81.4% within 60 min under the optimal conditions of 200 mg/L of catalyst dosage, 2.0g/L of PS dosage, and initial pH of 6. Mechanistic study demonstrated that both radical and non-radical reactive species play crucial roles in SMZ degradation and deep mineralization to CO 2 and H 2 O through the combination of SO 4 •− , HO•, and 1 O 2 . This research offers valuable insights for investigations into the relationship between active sites and catalytic performance in N-doped mesoporous carbon-activated persulfate degradation of organic pollutants.

The fate and risk of microplastic and antibiotic sulfamethoxazole coexisting in the environment

Zhang Xiaolei,Liu Lu,Chen Xiaoli,Li Ji,Chen Jiaxin,Wang Hongjie

With huge amount of plastic entering to the environment, microplastic pollution has become a great concern. Microplastic behavior in the environment is important to evaluate its harm to ecosystem and human beings. It has been found that microplastic can be used as a carrier to adsorb and enrich heavy metals or organic pollutants in water or soil. With the development of industry and medicine, antibiotics are improperly used in many countries and most of them end up in wastewater. This study investigates the adsorption behavior of sulfamethoxazole (SMX) antibiotic onto virgin and aged polyamide 6 (PA6) microplastics. The maximum adsorption amount was 0.089 mg SMX/g PA6 at 25 °C and pH 7 with initial SMX concentration of 2 mg/L. Results reveal that the adsorption was mainly due to the chemical bounding. The impact of pH, salinity, and humic acid on the adsorption have been studied, and it was found that the pH has significant impact on the adsorption. At pH 5, the adsorption amount was 0.27 mg/g which is two times higher than that at pH 7. The SMX adsorbed on PA6 tends to be more likely desorbed in reservoir water than in ultrapure water. For instance, the desorption amount of SMX from virgin PA6 was 0.15 mg/L in reservoir water but 0.10 mg/L in ultrapure water. The study indicates that microplastics have great threat to environment.

Polyacrylic acid-mediated sulfamethoxazole degradation by hydroxyl radicals during FeS oxidation under aerobic conditions

Dong Cheng,Jiaqing Luo,Runhao Ma,Fan Wu,Binbin Wang,Yingying Ma,Guangyu Lou,Feng He

Iron sulfide (FeS) nanoparticles demonstrate great potential for degrading organic contaminants under aerobic conditions through the production of hydroxyl radicals (•OH). However, its oxidative efficacy is often constrained by low electron utilization efficiency. In this study, we developed a polyacrylic acid (PAA)-mediated FeS oxidation system and investigated its effectiveness in sulfamethoxazole (SMX) degradation. The results indicate that PAA substantially enhanced the degradation of SMX by FeS at oxic conditions. As PAA dosage increased from 0.1 to 0.4 g/L, the observed degradation rate constants ( k obs ) of SMX were enhanced by 3- to 10-fold. Quenching experiments identified •OH as the primary reactive species responsible for SMX degradation. The electron utilization efficiency of FeS for •OH production was significantly increased from 0.3 % in FeS-only system to 2.1 % upon the addition of 0.4 g/L PAA. The enhancement was primarily attributed to the formation of dissolved Fe(II)-PAA complexes and the promotion of Fe redox cycling by PAA. By combining intermediate identification with density functional theory calculations, the degradation pathway of SMX was elucidated thoroughly. Additionally, the FeS/PAA/O 2 system exhibited exceptional degradation efficiency toward other common organic pollutants. X-ray diffraction and transmission electron microscopy revealed that PAA inhibited the formation of crystalline γ-FeOOH during FeS oxidation, which instead leads to the generation of amorphous structures. Collectively, this study provides fundamental insights into the oxidizing performance of FeS/PAA system and proposes a promising remediation technique for removing sulfonamide antibiotics.

Role of interfacial electron transfer reactions on sulfamethoxazole degradation by reduced nontronite activating H2O2

Hao-Jie Cui,Yaqi Ning,Cong Wu,Wei Peng,Dong Cheng,Lichu Yin,Weijun Zhou,Wenjuan Liao

It has been documented that organic contaminants can be degraded by hydroxyl radicals (•OH) produced by the activation of H 2 O 2 by Fe(II)-bearing clay. However, the interfacial electron transfer reactions between structural Fe(II) and H 2 O 2 for •OH generation and its effects on contaminant remediation are unclear. In this study, we first investigated the relation between •OH generation sites and sulfamethoxazole (SMX) degradation by activating H 2 O 2 using nontronite with different reduction extents. SMX (5.2–16.9 µmol/L) degradation first increased and then decreased with an increase in the reduction extent of nontronite from 22% to 62%, while the •OH production increased continually. Passivization treatment of edge sites and structural variation results revealed that interfacial electron transfer reactions between Fe(II) and H 2 O 2 occur at both the edge and basal plane. The enhancement on basal plane interfacial electron transfer reactions in a high reduction extent rNAu-2 leads to the enhancement on utilization efficiencies of structural Fe(II) and H 2 O 2 for •OH generation. However, the •OH produced at the basal planes is less efficient in oxidizing SMX than that of at edge sites. Oxidation of SMX could be sustainable in the H 2 O 2 /rNAu-2 system through chemically reduction. The results of this study show the importance role of •OH generation sites on antibiotic degradation and provide guidance and potential strategies for antibiotic degradation by Fe(II)-bearing clay minerals in H 2 O 2 -based treatments.

Rapid degradation of sulfamethoxazole by permanganate combined with bisulfite: efficiency, influence factors and mechanism

Shenglan Liu,Yiqing Liu,Jiewen Deng,Yongsheng Fu

Activated peracetic acid by Mn3O4 for sulfamethoxazole degradation: A novel heterogeneous advanced oxidation process

Runyu Zhou,Gaofeng Zhou,Yiqing Liu,Shenglan Liu,Shixiang Wang,Yongsheng Fu

In this study, a novel peracetic acid (PAA)-based advanced oxidation process using Mn 3 O 4 as a catalyst was proposed. A thorough sulfamethoxazole (SMX) removal could be achieved within 12 min in Mn 3 O 4 /PAA system at neutral pH. The characterization results of fresh and used Mn 3 O 4 suggested that ≡Mn(II), ≡Mn(III) and ≡Mn(IV) on Mn 3 O 4 were the Mn species for PAA activation , constituting the redox cycles of ≡Mn(II)/≡Mn(III) and ≡Mn(III)/≡Mn(IV) simultaneously. Organic radicals (i.e., CH 3 C(O)O • and CH 3 C(O)OO • ) were verified to be the dominant reactive species responsible for SMX degradation in Mn 3 O 4 /PAA system by radical scavenging experiments. The neutral condition was the most favorable pH for SMX removal in Mn 3 O 4 /PAA system and the increase of PAA or Mn 3 O 4 dosage could enhance SMX degradation. Presence of HCO 3 − and natural organic matter (NOM) could inhibit SMX degradation, while Cl − , NO 3 − and SO 4 2− had a negligible effect on SMX removal. The thorough SMX removal in successive experiments and characterization results of used Mn 3 O 4 suggested the good reusability and stability of Mn 3 O 4 for PAA activation. Based on six detected transformation products of SMX, hydroxylation, nitration, bond cleavage and coupling reaction were proposed to be its degradation pathways in Mn 3 O 4 /PAA system.

Non-radicals dominated degradation of sulfamethoxazole by a chemical-less microwave enhanced photolysis process

Wenchao Liao,Shuyi Liao,Su Xu,Qingsong Li,Linbo Han

A chemical-less microwave enhanced photolysis process (named MW/UV) was established for sulfamethoxazole (SMX) degradation and the mechanisms were specifically studied. 96.7% of SMX could be removed in an extremely short reaction time of 140 s under 400 W of microwave and 23.0 mW/cm 2 of UV light at 254 nm. The half-live of SMX was greatly shortened to 5 s in MW/UV process, compared with 67 s in UV process and 1386 s in MW process. MW/UV process was also effective when applied to complex real water matrices, such as river water, seawater, and synthetic waste water. Non-thermal effects of microwave were found to play an essential role in elevating photolysis degradation efficiency. The ROS formation detected by quenching experiments and EPR test showed that SMX degradation by MW/UV followed non-radicals dominated method, although 1 O 2 and OH co-existed in this system. 16 intermediates in total were detected by HPLC-Q-TOF and three degradation pathways based on 1 O 2 and OH oxidation were proposed according to the structural characteristics of the intermediates. Besides, toxicity evaluation of SMX and its intermediates revealed that MW/UV process could effectively reduce the toxicity of SMX. This study provides an efficient and promising scheme for practical SMX degradation.