查找使用阿拉丁产品的科研文献

Adsorption and removal of clofibric acid and diclofenac from water with MIEX resin

Xian Lu,Yisheng Shao,Naiyun Gao,Juxiang Chen,Yansen Zhang,Qiongfang Wang,Yuqi Lu

This study demonstrates the use of MIEX resin as an efficient adsorbent for the removal of clofibric acid (CA) and diclofenac (DCF). The adsorption performance of CA and DCF are investigated by a batch mode in single-component or bi-component adsorption system. Various factors influencing the adsorption of CA and DCF, including initial concentration, contact time, adsorbent dosage, initial solution pH, agitation speed, natural organic matter and coexistent anions are studied. The Langmuir model can well describe CA adsorption in single-component system, while the Freundlich model gives better fitting in bi-component system. The DCF adsorption can be well fitted by the Freundlich model in both systems. Thermodynamic analyses show that the adsorption of CA and DCF is an endothermic (ΔH o  > 0), entropy driven (ΔS o  > 0) process and more randomness exists in the DCF adsorption process. The values of Gibbs free energy (ΔG o  < 0) indicate the adsorption of DCF is spontaneous but nonspontaneous (ΔG o  > 0) for CA adsorption. The kinetic data suggest the adsorption of CA and DCF follow the pseudo-first-order model in both systems and the intra-particle is not the unique rate-limiting step. The adsorption process is controlled simultaneously by external mass transfer and surface diffusion according to the surface diffusion modified Biot number (Bi s ) ranging from 1.06 to 26.15. Moreover, the possible removal mechanism for CA and DCF is respectively proposed based on the ion exchange stoichiometry .

Degradation of diclofenac by Fe(II)-activated peracetic acid

Zhenran Wang,Hongle Shi,Shixiang Wang,Yiqing Liu,Yongsheng Fu

Degradation of Diclofenac by Loaded Solid Superbase-Activated Persulfate

Jiaqi Shi,Lei Wang,Shang Gao,Jianbo Huang,Hao Yang,Hao Lu,Shaohua Cao

Alkali-activated persulfate (PS) is widely used in situ in chemical oxidation processes; however, studies on the innovation of the alkali activation process are very limited. Two supported solid superbases, namely KNO3/γ-Al2O3(KAl) and KNO3/SBA-15/MgO (KSM), respectively, were prepared and used to activate persulfate to degrade DCF in this work. The results showed that the superbases elevated the solution pH once added and thus could catalyze persulfate to degrade diclofenac efficiently above pH 10.5. The catalytic efficiency of KAl was close to that of sodium hydroxide, and that of KSM was the highest. The mechanism might be that, in addition to raising the solution pH, some potassium existed as K2O2, which had a strong oxidizing effect and was conducive to DCF removal. Hydroxyl, sulfate and superoxide radicals were all found in the reaction system, among which hydroxyl might play the most important role. The material composition ratio, common anion and humic acid all had some influences on the catalytic efficiency. A total of five intermediates were found in the KSM/PS oxidation system, and six oxidation pathways, which were hydroxylation, dehydrogen, dechlorination, dehydration, decarboxylation, and C-N bond breakage, might be involved in the reaction process. Several highly toxic oxidation products that should be paid attention to were also proposed.Keywords:base-activated persulfate;catalytic mechanism;diclofenac;solid superbase

Kinetics and pathways of diclofenac degradation by heat-activated persulfate

Hongle Shi,Gaofeng Zhou,Yiqing Liu,Yongsheng Fu,Hongbin Wang,Peng Wu

In this study, the degradation of diclofenac (DCF) by heat-activated persulfate (HAP) was investigated. It was found that DCF could be degraded efficiently by HAP. The degradation of DCF followed the pseudo-first-order kinetic model, and the highest observed degradation rate constant (kobs) was obtained at pH 3. The sulfate radical was mainly responsible for DCF removal at pH < 7, whereas it was the hydroxyl radical at high pH. The elimination of DCF was enhanced with the increase in temperature or initial dosage of persulfate. Presence of Cu2+ and CO32− could improve DCF degradation, while an inhibition effect was observed in the presence of natural organic matter. According to the identified nine transformation products, the potential DCF degradation mechanism was proposed revealing five different reaction pathways, including hydroxylation, decarboxylation, formylation, dehydrogenation and C–N bond cleavage. This study indicates that HAP can effectively oxidize and degrade DCF, especially under acidic conditions.

Degradation kinetics and mechanism of diclofenac by UV/peracetic acid

Li Zhang,Yiqing Liu,Yongsheng Fu

In this work, the degradation kinetics and mechanism of diclofenac (DCF) by UV/peracetic acid (PAA) was investigated. The effects of pH, PAA dose and common water components such as inorganic ions and dissolved organic matter (DOM) on DCF degradation by UV/PAA were also evaluated. It was observed that the addition of PAA promoted the photodegradation of DCF due to the generation of reactive radicals in the photolysis of PAA, which was also confirmed by the radical scavenging experiment. The best degradation efficiency of DCF was obtained at pH 8.5. The removal of DCF was enhanced gradually with increasing PAA dose. Since NO3− is a photosensitive substance which can generate HO˙ under UV irradiation, its existence promoted the degradation of DCF. The presence of CO32− could slightly improve DCF degradation, which might be due to the role of generated carbonate radicals. Cl−, SO42− and Fe3+ had little effect on DCF removal, while Cu2+ could enhance DCF degradation because of its catalytic ability for PAA decomposition. An inhibition effect on DCF removal was observed in the presence of DOM, and it was more obvious in higher concentration of DOM. The elimination of total organic carbon (TOC) was low. According to the twelve reaction products detected in the UV/PAA system, the probable transformation mechanism of DCF was proposed exhibiting eight reaction pathways, i.e., hydroxylation, decarboxylation, formylation, dehydrogenation, dechlorination–hydrogenation, dechlorination–cyclization, dechlorination–hydroxylation and amidation. This study indicates that UV/PAA is a promising method for DCF removal from contaminated water.

Supramolecular Hydrogel Dexamethasone–Diclofenac for the Treatment of Rheumatoid Arthritis

Yanqin Song,Pufan Yang,Wen Guo,Panpan Lu,Congying Huang,Zhiruo Cai,Xin Jiang,Gangqiang Yang,Yuan Du,Feng Zhao

Rheumatoid arthritis (RA) severely affects patients’ quality of life and is commonly treated with glucocorticosteroids injections, like dexamethasone, which may have side effects. This study aimed to create a novel low dose of twin-drug hydrogel containing dexamethasone and diclofenac and explore its potential as a drug delivery system for an enhanced anti-inflammatory effect. Its characterization involved rheology, transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Furthermore, the hydrogel demonstrated thixotropic properties. The hydrogel exhibited no cytotoxicity against RAW 264.7 macrophages. Furthermore, the hydrogel demonstrated a significant anti-inflammatory efficacy by effectively downregulating the levels of NO, TNF-α, and IL-6 in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. The co-delivery approach, when intra-articularly injected in adjuvant-induced arthritis (AIA) rats, significantly alleviated chronic inflammation leading to reduced synovitis, delayed bone erosion onset, and the downregulation of inflammatory cytokines. The biocompatibility and adverse effect evaluation indicated good biological safety. Furthermore, the hydrogel demonstrated efficacy in reducing NF-κB nuclear translocation in LPS-induced RAW 264.7 macrophages and inhibited p-NF-kB, COX-2, and iNOS expression both in RAW 264.7 macrophages and the joints of AIA rats. In conclusion, the findings indicate that the hydrogel possesses potent anti-inflammatory activity, which effectively addresses the limitations associated with free forms. It presents a promising therapeutic strategy for the management of RA.

Simultaneously improving tabletability and solubility of diclofenac by cocrystallization with picolinamide

Chenyu Wu,Zijian Wang,Xu Han,Xinyi Yu,Changquan Calvin Sun,Zhengzheng Zhou

Diclofenac (DIC) is a nonsteroidal anti-inflammatory drug with poor tabletability and water solubility. In the present study, a new diclofenac-picolinamide cocrystal (DIC-PIC) was prepared to simultaneously improve its tabletability and solubility. The cocrystal was characterized using multiple techniques, such as X-ray diffraction, thermal methods and spectral analyses. The tabletability of DIC-PIC was significantly improved over DIC, which is attributed to the larger bonding area between crystals due to the higher plasticity of DIC-PIC, demonstrated by the lower in-die mean yield pressure, P y,i , of DIC-PIC (59.5 ± 0.6 MPa) than DIC (86.6 ± 1.4 MPa). The higher plasticity of DIC-PIC is consistent with the existence of a slip plane (001) in its crystal structure. The thermodynamic solubility of DIC-PIC is significantly higher than that of DIC (112 times higher in water and 22 times higher in pH = 6.8 buffer solution). Hence, the simultaneous improvement in tabletability and solubility of DIC-PIC overcomes two main barriers in developing DIC tablets, which makes it a promising candidate for developing a DIC tablet with improved performance.

Phosphorus-Coordinated Pd@MXene Electrocatalyst for Efficient Electrocatalytic Hydrodechlorination of Diclofenac

Lan-Ying Liu,Min-Hua Cui,Shi-Ming Niu,Xue-Dong Zhang,Xin-Hui Li,Wo-Long Wang,He Liu,Guo-Shuai Liu,Ai-Jie Wang

In this study, we synthesized a phosphorus-coordinated Pd@MXene catalyst to address the drawbacks associated with high noble metal usage, susceptibility to poisoning, and stability issues in the electrocatalytic hydrodehalogenation (EHDC) of recalcitrant halogenated pollutants. The phosphorus-coordinated Pd@MXene exhibited an EHDC performance comparable to that of the benchmark electrode (Pd@MX/CC) when tested on the model pollutant diclofenac (DCF). Notably, the phosphorus-coordinated Pd electrode demonstrated an 80% reduction in Pd usage and a 3.9-fold increase in Pd utilization efficiency. This improved performance was consistent across a wide range of pH values (pH 3, 7, and 11) and was sustained over 10 reaction cycles for the removal of DCF. Furthermore, the enhanced catalytic activity of the phosphorus-coordinated Pd electrode was achieved in the EHDC of various halogenated compounds. Importantly, the electrode exhibited a favorable tolerance to inorganic ions during the EHDC process. Density functional theory (DFT) calculations provided insights into the electronic configuration regulation of phosphorus-coordinated Pd@MXene, optimizing binding energies for H* and dechlorinated intermediates. The reported promotion effect of halogenated pollutants degradation by the phosphorus-coordination approach offers new insights into efficient EHDC systems toward water purification.

Molecularly imprinted polymer nanocarriers for recognition and sustained release of diclofenac

Lei Zheng,Hui Wang,Xiaomin Cheng

In this study, a series of imprinted poly(methacrylic acid- co -ethylene glycol dimethacrylate) nanocarriers for diclofenac and corresponding nonimprinted polymer nanocarriers have been synthesized in 4 different types of solvents by precipitation polymerization. The products were characterized by Fourier transform infrared, scanning electron microscopy, dynamic light scattering, and Brunauer-Emmett-Teller measurement. Results showed that uniformly sized molecularly imprinted polymer (MIP) nanospheres with relatively good porosity could only be obtained in acetonitrile. The effects of solvents on the recognition and release properties of polymer particles were also carefully investigated. The binding experiments indicated that MIPs prepared in acetonitrile displayed much higher binding capacity than other MIPs with a maximum binding capacity of 65.18 mg g −1 . The Scatchard analysis showed that synthetic MIPs have special recognition sites for diclofenac, while nonimprinted polymers have not. The Sips model could provide a best fit to the equilibrium data of nanocarriers over whole concentrations. The experimental data of an adsorption kinetic study were well fitted to the pseudo–second-order kinetic model, indicating the chemisorption mechanism between diclofenac and MIPs in the process of adsorption. The drug release of diclofenac from MIPs could well be described by the Ritger-Peppas model, suggesting a non-Fickian diffusion mechanism. In addition, we successfully used MIPs to extract diclofenac at low levels from fetal bovine serum.

Comparative investigation of diclofenac degradation by Fe2+/chlorine and Fe2+/PMS processes

Yu-qiong Gao,Yan-yan Rao,Han Ning,Ju-xiang Chen,Qian Zeng,Fu-xiang Tian,Nai-yun Gao

The degradation of diclofenac (DCF), a commonly used nonsteroidal anti-inflammatory drug, by Fe 2+ /chlorine and Fe 2+ /PMS processes was comparatively investigated. The influencing factors of pH, Fe 2+ and oxidant dosage on DCF degradation efficiency were evaluated and optimized. Typically, with an initial solution pH of 5, an Fe 2+ dosage of 70 μM, and a chlorine or PMS dosage of 70 μM, the degradation efficiency of DCF using the Fe 2+ /chlorine and Fe 2+ /PMS processes reached 94.2% and 79.7%, respectively, within 10 min. Quenching tests indicated the coexistence of •OH and RCS in the Fe 2+ /chlorine system, and both SO 4 ●– and •OH were identified in the Fe 2+ /PMS system. In addition, Fe(IV) was also identified to participate in DCF degradation in two systems based on the oxidation of PMSO to PMSO 2 . The degradation products and pathways of DCF were elucidated by LC/TOF/MS analysis and DFT calculations. It was assumed that the degradation pathway of DCF involves hydroxylation, dechlorination, decarboxylation, cleavage of the C-N bond, and chlorine substitution. In addition, trichloromethane (TCM), dichloroacetaldehyde (DCAL), dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM) were also detected in the Fe 2+ /chlorine process, and these chlorinated DBPs initially increased and then decreased with prolonged reaction time, indicating that Fe 2+ /chlorine is capable of controlling DBPs formation. Finally, the acute and chronic toxicity of DCF and its degradation products were evaluated by the ECOSAR program.

Effects of Microplastics on Diclofenac Degradation in the Permanganate–Manganese Dioxide System

Xinyu Lin,Yi-Bo Hu,Sai Yang,Wei Peng,Zhiling Zhao

Microplastics (MPs) are increasingly recognized as pervasive co-contaminants in aquatic environments, yet their impacts on advanced oxidation processes remain poorly understood. Herein, we systematically investigate the role of representative MPs in diclofenac (DCF) degradation within a permanganate–manganese dioxide (PM-MnO2) catalytic system. Results show that PM alone exhibits limited reactivity toward DCF, while MnO2significantly enhances DCF degradation. In the absence of MnO2, MPs increase PM consumption but do not influence DCF degradation, indicating that MPs primarily act as competing oxidant sinks. In contrast, under MnO2catalytic conditions, the effect of MPs strongly depends on their interaction with MnO2. Pre-adhesion of MPs onto MnO2suppresses DCF degradation by blocking active sites and inhibiting interfacial electron transfer. However, when MPs are introduced without pre-adhesion, no inhibition is observed; instead, a slight enhancement in DCF removal occurs. This promotion is attributed to in situ oxidation of MPs, which consumes PM and simultaneously generates secondary MnO2colloids that provide additional reactive interfaces. Further analysis reveals that PM consumption is decoupled from DCF degradation due to multi-pathway oxidant partitioning, including DCF oxidation, MP oxidation, and Mn redox cycling. These findings demonstrate that MPs can act as both inhibitors and promoters depending on their interaction mode with catalysts, highlighting the importance of catalyst accessibility and reaction sequence. This study provides new insights into the complex roles of MPs in catalytic oxidation systems and offers guidance for applying PM-based technologies in realistic water matrices.

Simultaneous removal of diclofenac, triclosan, and microplastics using graphene oxide-chitosan sponges

Mingi Ko,Jin-Hyuk Choi,Taesoon Jang,Soyeong Yoon,Jae-Woo Choi,Jeong-Ann Park

The interconnected macroporous graphene oxide-chitosan (GO-CS) sponge endowed the ability to simultaneously remove diclofenac (DCF), triclosan (TCS), and polystyren microplastics (PS MPs). Compared to the adsorption capacity for a single pollutant, the adsorption capacity for TCS and PS MPs was slightly decreased, indicating the partial competition of adsorption sites; however, the major adsorption sites for each pollutant differed. Fourier transform infrared and X-ray photoelectron spectroscopy analyses revealed that the adsorption of the pollutants onto the GO-CS sponge was influenced by electrostatic interactions, hydrogen bonding, and π-π interactions. The GO-CS sponge effectively removed DCF, TCS, and PS MPs even in real water samples. While DCF removal decreased in effluent and river water due to elevated pH and ion competition, TCS and PS MPs removal remained stable, driven by hydrophobic and π-π interactions. Under the flow-through condition, the highest adsorption capacities for DCF (20.49 mg/g), TCF (18.15 mg/g), and PS MPs (6.43 mg/g) were observed at the lowest flow rate (1.52 mL/min). All the breakthrough curves for the adsorption of the pollutants were described well by the Clark model, indicating their favorable and multilayer adsorption. Further, the sponge maintained its morphology and adsorption capacity (> 90.4 %) after three cycles of adsorption/desorption. Additionally, the GO-CS sponge exerted no toxicity on Daphnia magna (48 h of exposure) and no growth inhibition effect on Pseudokirchneriella subcapitata (72 h of exposure). The sponge lost 54.28 % of its total weight after being buried in the soil for 35 days, verifying its biodegradability.