Comparative study of degradation of ketoprofen and paracetamol by ultrasonic irradiation: Mechanism, toxicity and DBP formation.

The present study comparatively investigated the ultrasonic degradation of ketoprofen (KET) and paracetamol (PCT) in water. Ultrasonic irradiation at 555 kHz achieved rapid degradation of KET and PCT in water, the removal efficiencies of KET (2.5-80 µM) and PCT (2.5-80 µM) reached 87.7%-100% and 50.6%-86.9%, respectively, after 10 min of reaction under an ultrasonic power of 60 W. The degradation behaviors of both KET and PCT followed the Langmuir-Hinshelwood model. KET was eliminated faster than PCT because of its higher hydrophobicity. Acidic media favored ultrasonic degradation of KET and PCT. Organic compounds in water matrices exerted a great negative effect on the ultrasonic degradation rates of KET and PCT major by competing with target compounds with the generated radicals at the bubble/water interfacial region. The effects of anions were species dependent. The introduction of ClO4- and Cl- enhanced KET and PCT degradation to different extents, while the introduction of HCO3- posed a negative effect on both KET and PCT. KET and PCT degradation are accompanied by the generation of several transform intermediates, as identified via LC/MS/MS analysis, and corresponding reaction pathways have been proposed. A human umbilical vein endothelial cell (HUVEC) toxicity evaluation indicated that ultrasonic treatment was capable of controlling the toxicity of KET or PCT degradation. Of note, the enhanced formation of disinfection byproducts (DBPs), i.e., trichloromethane (TCM) and trichloronitromethane (TCNM), was found due to chlorination after ultrasonic treatment for both KET and PCT.

Electrochemically activated peroxymonosulfate for the abatement of chloramphenicol in water: performance and mechanism.

In this study, electrochemically activated peroxymonosulfate (EC/PMS) with a sacrificial iron electrode was used for the removal of chloramphenicol (CAP) from water. Compared to electrolysis alone, peroxymonosulfate (PMS) alone, and Fe2+/PMS, EC/PMS significantly enhanced the CAP degradation. Various parameters, such as the applied current, electrolyte concentration, and PMS dose, were investigated to optimize the process. In addition, acidic conditions facilitated the CAP degradation. The presence of Cl- slightly enhanced the CAP degradation, while both HCO3- and NO3- exhibited an inhibitory effect on the CAP degradation. The floccules were also analyzed after the reaction by XPS and XRD. Quenching experiments indicated that both sulfate radicals (SO4●-) and hydroxyl radicals (•OH) were responsible for the CAP degradation. In addition, the degradation products were identified by LC/TOF/MS, and the degradation pathways were proposed accordingly. These results indicated that EC/PMS is a promising treatment process for the remediation of water polluted by CAP.

MoS2-assisted Fe2+/peroxymonosulfate oxidation for the abatement of phenacetin: efficiency, mechanisms and toxicity evaluation.

In this study, molybdenum disulfide (MoS2) was chosen as a co-catalyst to enhance the removal efficiency of phenacetin (PNT) in water by a ferrous ion-activated peroxymonosulfate (Fe2+/PMS) process. Operating parameters, such as the initial solution pH and chemical dose on PNT degradation efficiency were investigated and optimized. Under an initial pH of 3, an Fe2+ dose of 25 µM, a PMS dose of 125 µM and a MoS2 dose of 0.1 g L-1, the degradation efficiency of PNT reached 94.3%, within 15 min. The presence of common water constituents including Cl-, HCO3 -, SO4 2- and natural organic matter (NOM) will inhibit degradation of PNT in the MoS2/Fe2+/PMS system. Radical quenching tests combined with electron paramagnetic resonance (EPR) results indicated that in addition to free radical species (˙OH, SO4˙- and O2˙-), nonradical reactive species (1O2) were also crucial for PNT degradation. The variations in the composition and crystalline structure of the MoS2 before and after the reaction were characterized by XPS and XRD. Further, the degradation pathways of PNT were proposed according to the combined results of LC/TOF/MS and DFT calculations, and primarily included hydroxylation of the aromatic ring, cleavage of the C-N bond of the acetyl-amino group, and cleavage of the C-O bond of the ethoxy group. Finally, toxicity assessment of PNT and its products was predicted using the ECOSAR program.

Comparison of UV-induced AOPs (UV/Cl2, UV/NH2Cl, UV/ClO2 and UV/H2O2 ) in the degradation of iopamidol: Kinetics, energy requirements and DBPs-related toxicity in sequential disinfection processes.

The UV-induced advanced oxidation processes (AOPs, including UV/Cl2, UV/NH2Cl, UV/ClO2 and UV/H2O2 ) degradation kinetics and energy requirements of iopamidol as well as DBPs-related toxicity in sequential disinfection were compared in this study. The photodegradation of iopamidol in these processes can be well described by pseudo-first-order model and the removal efficiency ranked in descending order of UV/Cl2  > UV/H2O2  > UV/NH2Cl > UV/ClO2  > UV. The synergistic effects could be attributed to diverse radical species generated in each system. Influencing factors of oxidant dosage, UV intensity, solution pH and water matrixes (Cl- , NH4 + and nature organic matter) were evaluated in detail. Higher oxidant dosages and greater UV intensities led to bigger pseudo-first-order rate constants (Kobs) in these processes, but the pH behaviors exhibited quite differently. The presence of Cl- , NH4 + and nature organic matter posed different effects on the degradation rate. The parameter of electrical energy per order (EE/O) was adopted to evaluate the energy requirements of the tested systems and it followed the trend of UV/ClO2  > UV > UV/NH2Cl > UV/H2O2  > UV/Cl2 . Pretreatment of iopamidol by UV/Cl2 and UV/NH2Cl clearly enhanced the production of classical disinfection by-products (DBPs) and iodo-trihalomethanes (I-THMs) during subsequent oxidation while UV/ClO2 and UV/H2O2 exhibited almost elimination effect. From the perspective of weighted water toxicity, the risk ranking was UV/NH2Cl > UV/Cl2 > UV > UV/H2O2 > UV/ClO2 . Among the discussed UV-driven AOPs, UV/Cl2 was proved to be the most cost-effective one for iopamidol removal while UV/ClO2 displayed overwhelming advantages in regulating the water toxicity associated with DBPs, especially I-THMs. The present results could provide some insights into the application of UV-activated AOPs technologies in tradeoffs between cost-effectiveness assessment and DBPs-related toxicity control of the disinfected waters containing iopamidol.

Persulfate activation by nano zero-valent iron for the degradation of metoprolol in water: influencing factors, degradation pathways and toxicity analysis.

In this study, nano zero-valent iron (nZVI) was utilized to activate persulfate (PS) for the degradation of metoprolol (MTP), a commonly used drug for curing cardiovascular diseases, in water. Quenching tests indicated that both the sulfate radical (SO4˙-) and hydroxyl radical (˙OH) contributed to the degradation of MTP, while SO4˙- seemed to play a large role under natural pH conditions. Batch tests were conducted to investigate the effects of several influencing factors, such as PS concentration, initial MTP concentration, pH, temperature and common anions, on the degradation performance of MTP. Generally, lower MTP concentration and pH values, and higher PS concentration and temperature favoured MTP degradation. HCO3 -, NO3 - and SO4 2- were found to inhibit MTP degradation, while Cl- enhanced MTP degradation. Several corrosion products of nZVI, including Fe3O4, Fe2O3 and FeSO4, were formed during the reaction, which was reflected by the combined XRD and XPS analysis. Degradation pathways of MTP were proposed according to the identified transformation products, and the peak areas of the major products along with the time were also monitored. Finally, the toxicity of the reaction solution was assessed by experiments using Aliivibrio fischeri. Overall, it could be concluded that nZVI/PS might be a promising method for the rapid treatment of MTP-caused water pollution.

Comparative evaluation of metoprolol degradation by UV/chlorine and UV/H2O2 processes.

The degradation of metoprolol (MTP), a ß-blocker commonly used for cardiovascular diseases, by UV/chlorine and UV/H2O2 processes was comparatively evaluated. MTP direct photolysis at 254 nm could be neglected, but remarkable MTP degradation was observed in both the UV/chlorine and UV/H2O2 systems. Compared with UV/H2O2, UV/chlorine has a more pronounced MTP degradation efficiency. In addition to primary radicals (OH and Cl), secondary radicals (ClO and Cl2-) played a pivotal role in degrading MTP by UV/chlorine process. The relative contributions of hydroxyl radicals (OH) and reactive chlorine species (RCS) in the UV/chlorine system varied at different solution pH values (i.e., the contribution of RCS increased from 57.7% to 75.1% as the pH increased from 6 to 8). The degradation rate rose as the oxidant dosage increased in the UV/chlorine and UV/H2O2 processes. The presence of Cl- slightly affected MTP degradation in both processes, while the existence of HCO3- and HA inhibited MTP degradation to different extents in both processes. In terms of the overall cost of electrical energy, UV/chlorine is more cost efficient than UV/H2O2. The degradation products during the two processes were identified and compared, and the degradation pathways were proposed accordingly. Compared with the direct chlorination of MTP, pre-oxidation with UV/chlorine and UV/H2O2 significantly enhanced the formation of commonly known DBPs. Therefore, when using UV/chlorine and UV/H2O2 in real waters to remove organic pollutants, the possible risk of enhanced DBP formation resulting from the degradation of certain pollutants during post-chlorination should be carefully considered.

Ultrasound-assisted heterogeneous activation of persulfate by nano zero-valent iron (nZVI) for the propranolol degradation in water.

This study investigated the degradation of propranolol (PRO), a beta (ß)-blockers, by nano zero-valent iron (nZVI) activated persulfate (PS) under ultrasonic irradiation. Effects of several critical factors were evaluated, inclusive of PS concentration, nZVI dosage, ultrasound power, initial pH, common anions, and chelating agent on PRO degradation kinetics. Higher PS concentration, nZVI dosage and ultrasound power as well as acidic pH favored the PRO degradation. Conversely, anions and chelating agent took on the inhibitory effect towards PRO degradation to different extents. Furthermore, the variations of morphology and surface composition of nZVI before and after the reaction were characterized by TEM, XRD and XPS. Finally, on the basis of identified degradation intermediates by LC/MS/MS analysis, this work tentatively proposed the degradation pathways. These encouraging results suggest that US/nZVI/PS process is a promising strategy for the treatment of PRO-induced water pollutant.

A new multifunctional hydroxytyrosol-clofibrate with hypolipidemic, antioxidant, and hepatoprotective effects.

Oxidative stress has been regarded as the leading mechanism of the hepatotoxicity of clofibrate (CF). To achieve multifunctional novel hypolipidemic agents with hypolipidemia, antioxidant, and ameliorating liver injury, clofibric acid derivative hydroxytyrosol-clofibrate (CF-HT) was synthesized by molecular hybridization. CF-HT exhibited significant hypolipidemia, reducing serum triglyceride (TG), total cholesterol (TC), and malonaldehyde (MDA) by 30%, 33%, and 29% in hyperlipidemic mice induced by Triton WR 1339. CF-HT also shown hepatoprotective effect, a significant decrease in hepatic indices toxicity was observed, i.e. aspartate and lactate transaminases (AST and ALT) activities, alkalines phosphatases (ALP), and total bilirubin (TBIL) levels. The liver weight and liver coefficient were also ameliorated. Serum superoxide dismutase (SOD) was significantly elevated, and serum catalase (CAT) and malondialdehyde (MDA) content were remarkably restored. The hepatic glutathione (GSH) content was obviously increased and hepatic oxidized glutathione (GSSG) content was reduced dramatically by CF-HT, as compared to the CF treated mice (p < 0.05). Moreover, the histopathological damage that hepatocyte hyperplasia and hypertrophy was also significantly ameliorated by treatment with CF-HT. Therefore, the results indicated that CF-HT exerted more potent hypolipidemic activity and definite hepatoprotective effect which may mainly be associated with its antioxidative property in mice.

Hydroxytyrosol nicotinate, a new multifunctional hypolipidemic and hypoglycemic agent.

Hydroxytyrosol (HT) is a natural polyphenol antioxidant that exists in olive oil. In the study of multifunctional hypolipidemic of nicotinic derivatives, we found that hydroxytyrosol nicotinate (HT-N) incorporation of niacin with HT displayed ?-glucosidase inhibitory activities in vitro, such as yeast ?-glucosidase (IC50?=?117.72??M) and rat intestinal ?-glucosidases maltase (IC50?=?31.86??M) and sucrase (IC50?=?22.99??M), and had a good control of postprandial blood glucose (PBG). HT-N shown significantly hypoglycemic action by 16.9% and protection of pancreatic tissue in type 2 diabetic mellitus (T2DM) mouse model. HT-N also shown a potent antioxidant activity and property of anti-glycation in vitro, which were benefit for ameliorating diabetic complications. Moreover, HT-N exhibited much significant hypolipidemia, lowering plasma triglyceride (TG), total cholesterol (TC), and malonaldehyde (MDA) by 34.6%, 45.8% and 32.1% respectively, in hyperlipidemic mice induced by Triton WR 1339. The results indicated that HT-N has hypolipidemic, hypoglycemic and antioxidant actions. All these properties could be conducive to amelioration of oxidative stress, hyperlipidemia, and diabetes that HT-N may serve as a multifunctional potential therapeutic strategy in diabetic patients with hyperlipidemia.

Oxidation of the ß-blocker propranolol by UV/persulfate: Effect, mechanism and toxicity investigation.

In this study, the degradation of propranolol (PRO) by UV/persulfate process was systematically investigated. Direct photolysis of PRO was limited due to its low quantum yield, while the PRO degradation efficiency can be greatly promoted by the combination of persulfate and UV irradiation. Radical scavenging tests showed that both SO4- and OH contributed to the removal of PRO, with SO4- playing a more important role. The degradation rate of PRO was improved by increasing the persulfate dose and initial solution pH consistent with pseudo-first-order reaction kinetics. The effects of common water constituents were species dependent. HCO3- and Cl- promoted PRO degradation. By contrast, NO3- and HA were found to inhibit PRO degradation. A total of nine degradation products were identified by LC/MS/MS, which mainly derived from the ring-opening attack on the naphthalene group or oxidation of the amino moiety by SO4- and OH. Finally, the toxicity of the reaction mixtures was also assessed using luminescent bacteria Vibrio fischeri, and the results indicated that UV/persulfate is capable of controlling the toxicity of PRO degradation.

Kinetic and mechanistic investigations of the degradation of propranolol in heat activated persulfate process.

This study investigated the heat activated persulfate (heat/PS) process in the degradation of propranolol from water. Various factors (e.g., temperature, persulfate dose, initial pH and natural water constituent) on PRO degradation kinetics have been investigated. The results showed that the PRO degradation followed a pseudo-first-order kinetics pattern. As temperature rises, the pseudo-first-order rate constant (k obs) was improved significantly, and the k obs determined at 40-70 °C satisfied the Arrhenius equation, yielding an activation energy of 99.0 kJ mol-1. The radical scavenging experiments and the EPR tests revealed that both SO4˙- and ·OH participated in degrading PRO, with SO4˙- playing a dominant role. Higher PS concentration and neutral pH favored PRO degradation. The impact of Cl- and HCO3 - were concentration-dependent. A lower concentration of Cl- and HCO3 - could accelerate PRO degradation, while the presence of HA showed inhibitory effects. Seven degradation products were recognized through LC/MS/MS analysis. Cleavage of ether bond, hydroxylation, and ring-opening of naphthol moiety are involved in the PRO's degradation pathway. Finally, the formation of disinfection byproducts (DBPs) before and after pre-treated by heat/PS was also evaluated. Compared with direct chlorination of PRO, the heat/PS pre-oxidation greatly impacted the DBPs formation. The higher PRO removal efficiency in natural water indicated the heat/PS process might be capable of treating PRO-containing water samples, however, its impacts on the downstream effect on DBPs formation should be also considered.

Phototransformation of iodate by UV irradiation: Kinetics and iodinated trihalomethane formation during subsequent chlor(am)ination.

The photodegradation of IO3- at 254nm and the formation of iodinated trihalomethanes (I-THMs) during subsequent chlorination or chloramination in the presence of natural organic matter (NOM) were investigated in this study. The thermodynamically stable IO3- can be degraded by UV irradiation with pseudo-first order kinetics and the quantum yield was calculated as 0.0591moleinstein-1. Solution pH posed no remarkable influence on the photolysis rate of IO3-. The UV phototransformation of IO3- was evidenced by the determination of iodide (I-) and hypoiodous acid (HOI) in solution. NOM sources not only enhanced the photodegradation rate of IO3- by photoejecting solvated electrons, but also greatly influenced the production I-THMs in subsequent chlor(am)ination processes. In UV irradiation and sequential oxidation processes by chlorine or chloramine, the I-THMs formation was susceptible to NOM sources, especially the two major fractions of aqueous humic substances (humic acid and fulvic acid). The toxicity of disinfected waters greatly increased in chloramination over chlorination of the UV photodecomposed IO3-, as far more I-THMs especially CHI3, were formed. As "the fourth iodine source" of iodinated disinfection by-products, the occurrence, transportation and fate of IO3- in aquatic environment should be of concern instead of being considered a desired iodine sink.

Degradation of florfenicol in water by UV/Na2S 2O 8 process.

UV irradiation-activated sodium persulfate (UV/PS) was studied to degrade florfenicol (FLO), a phenicol antibiotic commonly used in aquaculture, in water. Compared with UV/H2O2 process, UV/PS process achieves a higher FLO degradation efficiency, greater mineralization, and less cost. The quantum yield for direct photolysis of FLO and the second-order rate constant of FLO with sulfate radicals were determined. The effects of various factors, namely PS concentration, anions (NO3 (-), Cl(-), and HCO3 (-)), ferrous ion, and humic acid (HA), on FLO degradation were investigated. The results showed that the pseudo-first-order rate constant increased linearly with increased PS concentration. The tested anions all adversely affected FLO degradation performance with the order of HCO3 (-) > Cl(-) > NO3 (-). Coexisting ferrous ions enhanced FLO degradation at a Fe(2+)/PS molar ratio under 1:1. HA significantly inhibited FLO degradation due to radical scavenging and light-screening effect. Toxicity assessment showed that it is capable of controlling the toxicity for FLO degradation. These findings indicated that UV/PS is a promising technology for water polluted by antibiotics, and the treatment is optimized only after the impacts of water characteristics are carefully considered.

Factors affecting sonolytic degradation of sulfamethazine in water.

In this study, the major factors affecting sonolytic degradation of sulfamethazine (SMT), a typical pharmaceutically active compound, in water were evaluated. The factors tested included two operational parameters (i.e. initial SMT concentration and ultrasonic power), three dissolved gases (i.e. Ar, O2 and N2), five most frequently found anions in water (NO3(-),Cl(-),SO4(2-),HCO3(-)andBr(-)), ferrous ion (Fe(2+)), and four alcohols (methanol, ethanol, isopropyl alcohol, tert-butyl alcohol). Typically, the degradation rate was increased with the increasing initial SMT concentration and power. The degradation rate was accelerated in the presence of argon or oxygen, but inhibited by nitrogen. Effects of anions on the ultrasonic treatment were species-dependent. The SMT degradation rate was slightly inhibited by NO3(-),Cl(-),and,SO4(2-) but significantly improved by HCO3(-)andBr(-). The negative effects of alcohols acted as hydroxyl radicals scavengers with the following order: tert-butyl alcohol>isopropyl alcohol>ethanol>methanol. The synergetic effect of ferrous ion was mainly due to production of additional hydroxyl radicals (·OH) through Fenton chemistry. LC/MS/MS analysis indicated that the degradation of SMT by ultrasonic irradiation is mainly ascribed to ·OH oxidation. Of interest, although the SMT could be rapidly degraded by ultrasonic irradiation, the degradation products were rarely mineralized. For example, ~100% of 180 µM SMT was decomposed, but only 8.31% TOC was reduced, within 2h at an irradiation frequency of 800 kHz and a power of 100 W. However, the products became much biodegradable (BOD5/COD was increased from 0.04 to 0.45). Therefore, an aerobic biological treatment may be an appropriate post-treatment to further decompose the SMT degradation products.

Adsorption of microcystin-LR from water with iron oxide nanoparticles.

Adsorption of microcystin-LR (MC-LR) from water using iron oxide (alpha-Fe2O3) nanoparticles was investigated in this study. Adsorption of MC-LR adsorption was well-described by a pseudo second order kinetics model and Freundlich and Langmuir isotherm equations at 15 to 35 degrees C. Thermodynamic analysis showed that the Gibbs free energy was negative, whereas standard enthalpy and entropy changes were positive at this temperature range. These findings suggest that the adsorption of MC-LR on iron oxide nanoparticles was spontaneous and endothermic. The effects of initial pH, inorganic cations, and competing compounds with carboxyl groups on absorption of MC-LR were also evaluated. Typically, adsorption efficiency decreased with increasing pH from 2 to 11. Sodium ions did not appear to significantly affect MC-LR adsorption, whereas calcium ions slightly enhanced the MC-LR adsorption capacity of the iron oxide nanoparticles. Moreover, the inhibiting effect of competing organic compounds was increased with increasing numbers of carboxyl groups, as follows: citric acid (3)>oxalic acid (2)>benzoic acid (1).

[Studies on the chemical constituents of the volatile oil from Radix Cudramiae].

OBJECTIVE: To study the chemical constituents of the volatile oil from Radix Cudramiae. METHOD: The oil was obtained by steam distillation. The chemical compositions were separated and identified by GC-MS. The relative contents in the oil were determined by area nomalization. RESULT: Sixty-four compounds were obtained from Radix Cudramiae. The relative contents of twenty-three compounds were more than 1%. The highest relative content was L-linalool (9.852%). CONCLUSION: Sixty-four compounds characterized by GC-MS analysis were obtained from Radix Cudramiae for the first time.