Improved catalytic performance of ZnO via coupling with CoFe2O4 and carbon nanotubes: A new, photocatalysis-mediated peroxymonosulfate activation system, applied towards Cefixime degradation.

In this study, a ternary ZnO@spinel cobalt ferrite@carbon nanotube magnetic photocatalyst (ZSCF@CNT) was successfully synthesized and used to activate peroxymonosulfate (PMS) for Cefixime (CFX) antibiotic degradation under UVC irradiation. The morphology, optical, structural, and physicochemical properties of ZSCF@CNT were characterized and analyzed by XPS, XRD, FESEM-EDX, TEM, BET, VSM, UV-vis DRS and PL analysis. The results indicated that the ternary ZSCF@CNT photocatalyst exhibited superior catalytic activity on CFX elimination than that of individual components and binary composite catalysts, in which CFX with was rapidly removed under UVC irradiation and PMS. The effect of operational parameters including initial PMS, catalyst, and CFX concentrations and solution pH on the catalytic activity was investigated in detail; the optimal conditions were: pH: 7.0, catalyst: 0.3 g/L, PMS: 3.0 mM, leading to total CFX (10 mg/L) elimination in ∼20 min. Based on the radical scavenger tests, various radicals and non-radical species including sulfate, hydroxyl and superoxide radicals, singlet oxygen and electrons were involved in the ZSCF@CNT/PMS/UVC system. The high surface area, reduced agglomeration formation and excellent separation of photogenerated electron-hole pairs embodied in ZSCF@CNT photocatalyst conferred its superior catalytic activity and stability. The results from the tests in real water matrices revealed that ZSCF@CNT could be a promising photocatalyst to activate PMS for actual aqueous matrices' treatment.

The effects of cadmium exposure in the induction of inflammation.

Inflammation is a physiological process essential for maintaining homeostatic mechanisms in human, but however, exaggerated inflammatory responses are closely related to many chronic diseases. Cadmium (Cd) is a heavy metal with high toxicity when present in food, water and air has the potential of eliciting inflammatory reactions, with a major health risk to human. This review aimed to elucidate on the major routes of Cd exposure, the main organs affected by the exposure, the degree of toxicity as well as the roles of the toxic effects on the immune system which results to inflammatory responses. Immune modulation by Cd may cause serious adverse health effects in humans. Various studies have highlighted the ability of Cd as an environmental pollutant involved in the modulation of the innate, adaptive and mucosal immune responses in relations to the release of chemokine, gene expression, and susceptibility to microbial infections.

Efficient clean-up of waters contaminated with diazinon pesticide using photo-decomposition of peroxymonosulfate by ZnO decorated on a magnetic core/shell structure.

In the present study, ZnO nanoparticles were anchored on a magnetic core/shell structure (SiO2@Fe3O4) to perpetrate ZnO@SiO2@Fe3O4 and then coupled with UV light as a heterogeneous nanocatalyst for activating peroxymonosulfate (PMS) into diazinon (DZ) degradation. Several techniques like XRD (X-ray diffraction), BET (Brunaeur, Emmett and Teller), TEM (Transmission electron microscope), FESEM (Field emission-scanning electron microscope) coupled with EDS (Energy Dispersive X-ray Spectrometer), PL (photoluminescence), VSM (Vibrating Sample Magnetometer) and UV-vis diffuse reflectance spectroscopy (DRS) were applied for identification of catalyst features. A possible mechanism for PMS activation and DZ degradation was proposed in details. The effect of solution pH, various concentrations of catalyst, PMS and DZ, quenching agents, different chemical oxidants and co-existing anions was assessed as operating factors to determine the optimum conditions. PMS decomposed effectively in coupling with ZnO@SiO2@Fe3O4 and UV. At optimal conditions, over 95 and 56% of DZ and TOC were removed during 60 min reaction, respectively. The complete degradation of DZ was confirmed using its absorption peak in UV-vis spectra analysis over 60 min treatment. A wide variety of free radicals was identified during quenching tests. HO• and h+ played a pivotal role in the degradation process of DZ. Decreasing the degradation efficiency in the presence of anions was as Cl- > CO32- > NO3- > PO43- > SO42- > HCO3-. A negligible amount of leaching Fe (<0.2 mg/L) was found for ZnO@SiO2@Fe3O4, indicating that the catalyst possesses a high stability in oxidation systems. In addition, a significant potential was achieved in reusing of catalyst within five consecutive runs. In conclusion, ZnO@SiO2@Fe3O4/PMS/UV hybrid system can be utilized as a promising advanced oxidation process into efficient degradation of pesticides, thanks to easy recovery, high catalytic activity, co-production of different reactive species and high durability and recyclability potential.

Impacts of drought phenomenon on the chemical quality of groundwater resources in the central part of Iran-application of GIS technique.

In the recent decades, global warming has caused water shortages all over the world. This study aimed to investigate the impacts of drought caused by climate change on the chemical quality of groundwater in Saveh County, Markazi province, Iran. The physicochemical parameters of 29 wells were analyzed by the Standardized Precipitation Index (SPI) during the drought period 2004-2015. Wilcox and Schoeller diagrams were applied to evaluate the water quality of wells for irrigation and drinking purposes, respectively. Schoeller diagram was consulted to show the relative concentrations of anions and cations typically expressed in milliequivalents per liter. Also, the Wilcox diagram was consulted to determine the suitability of water for agriculture purposes. Finally, the geographic information system was applied to the zoning of the groundwater quality parameters. According to the results, almost 90% of wells were in the category of "very salty and harmful for agriculture uses" in the last year of the study period (2015). The Schoeller diagram suggests that the water quality of 72.5, 10.4, 65.5, 100, 44.9, and 69% of wells were inappropriate and exceeded the Iranian National Standard level, in terms of TDS, TH, Na+، Mg2+, Cl-, and SO42- in 2015, respectively. A decrease in yearly average precipitation during the studied period has not only caused overuse of groundwater as the primary water resources but also led to a significant decline in its chemical quality.

Enhancing oxygen reduction reaction performance through eco-friendly chitosan gel-assisted molten salt strategy: Small NiCo alloy nanoparticles decorated with high-loading single Fe-NX.

We developed an effective and eco-friendly strategy using chitosan gel-molten salt to achieve high loading (2.23 At. %) of single Fe-NX as assistive active sites. These sites were combined with small NiCo alloy NPs distributed on porous carbon aerogels to boost the ORR performance. The FeSAs-NiCo alloy@N-C sphere exhibits exceptional mass activity and specific activity of 3.705 A.mg-1 and 8.79 mA.cm-2(ECSA), respectively, at 0.85 V versus RHE. It has a superior onset potential of 1.08 V versus RHE, surpassing that of its nanoparticle Fe counterpart and NiCo alloy@N-C sphere. The significant improvement in ORR performance of the FeSAs-NiCo alloy@N-C sphere could be attributed to the positive effects of increased lattice strain due to the single atoms of Fe-NX hybridized with small NiCo alloy NPs. The chitosan gel-assisted molten salt strategy and assistive active sites of Fe-NX hybridized with NiCo alloy NPs regulate the electronic properties of the FeSAs-NiCo alloy@N-C sphere, both geometrically via lattice strain mismatch and electronically through shifting of the d-band center. This could influence the binding energies for oxygen and/or oxygen reduction intermediate adsorption/desorption. The additional improvement in the ORR performance of the FeSAs-NiCo alloy@N-C sphere also benefits from having a lower electrochemical activation energy.

US-assisted catalytic degradation of paraquat using ZnO/Fe3O4 recoverable composite: Performance, toxicity bioassay test and degradation mechanism.

In this study, the ZnO/Fe3O4 catalyst was used as an active catalyst for the oxidation of Paraquat (PQ) herbicide in aqueous solution under ultrasonic (US) waves. FTIR, XRD, FE-SEM, and VSM analyses were performed to characterize the synthesized catalyst. Studies on the effect of radical scavengers were also carried out and the amount of organic matter degradation was determined by measuring the TOC. Under the optimized conditions (catalyst concentration = 0.75 g/L, herbicide concentration = 10 ppm, US power = 70w), the degradation and mineralization rates of the herbicide were acquired as 96.1% and 68% within 60 min, respectively. The quenching tests showed that the hydroxyl (oOH) radical was the most effective oxidant agent in the degradation process of the PQ under ZnO/Fe3O4/US system. The toxicity of treated effluent assayed by Daphnia Magna was decreased from %73.16 in raw samples to %7.2 in the treated samples, during 96 h. Finally, it can be concluded that ZnO/Fe3O4/US process can be successfully performed as an effective process to herbicides in aqueous solutions, due to the high efficiency and excellent catalytic activity.

Experimental design, modeling and mechanism of cationic dyes biosorption on to magnetic chitosan-lutaraldehyde composite.

Magnetic separation of toxic dyes has become a potential and effective method in wastewater treatments. In present research, a facile in situ one step co-precipitation synthetic approach is used to develop water-dispersible Fe3O4/Chitosan/Glutaraldehyde nanocomposites (MCS-GA) as an efficient adsorbent for the removal of Crystal Violet (CV) from aqueous solution. The physicochemical properties of the MCS-GA were investigated using FTIR, SEM, TEM, XRD, BET, and VSM techniques. 5-level and 3-factors central composite design (CCD) combined with the response surface methodology (RSM) was applied to investigate the statistical relationships between independent variables i.e. initial pH, adsorbent dosage, initial dye concentration and adsorption process as response. The optimal values of the parameters for the best efficiency (99.99%) were as follows: pH of 11, the initial dye concentration of 60 mg L-1 and MCS-GA dosage of 0.817 g L-1, respectively. The adsorption equilibrium and kinetic data were fitted with the Langmuir monolayer isotherm model (qmax: 105.467 mg g-1, R2: 0.996) and pseudo-second order kinetics (R2: 0.960). Thermodynamic parameters (R2 > 0.941, ΔH°: 690.609-896.006 kJ mol-1, ΔG°: -1.6849 to -13.4872 kJ mol-1, ΔS°: 0.168-0.232 kJ mol-1 K-1) also indicated CV adsorption is feasible, spontaneous and endothermic in nature. Overall, taking into account the excellent efficiency, good regeneration and acceptable performance in real terms, MCS-GA can be introduced as a promising absorbent for dyes removal from the textile wastewater.

Evaluation and analysis of municipal solid wastes in Tehran, Iran.

Waste management for municipal solid waste is considered a public health services, providing citizens with a system of disposing of their waste in an environmentally sound and economically feasible way. The amount and composition of waste generated comprise the basic information needed for the planning, operation and optimization of waste management systems. In this study, paper and plastic quantity changes in the MSW (municipal solid waste) of the region 10 of Tehran city were evaluated. This study was conducted in 6 months, in the summer and autumn seasons, at the region 10 of Tehran city. In this study, paper and plastic were segregated and data were analyzed by SPSS software. The paper parameter of solid wastes was consisted of folder paper, cardboard and used newspaper. The plastic parameter of solid wastes was consisted of plastic materials, plastic house shoes, plastic sack, nylon sack, linoleum, radiology photograph and PET. Samples were collected and weighed daily. The total quantity of paper and plastic portion of this region solid waste were 203,930 Kg and 180,101 Kg, respectively. The percentage of paper and plastic portion of this region solid waste also were 6.82% and 6.03%, respectively. The analyses showed a significant difference between these parameters and season, some months and days (P-value < 0.05). So, because of the results of this study and economical issues, the paper and plastic segregation from generated source point and recycling them are important.

Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater.

Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

Biodegradation of 2,4-dinitrophenol with laccase immobilized on nano-porous silica beads.

Many organic hazardous pollutants, including 2,4-dinitrophenol (2,4-DNP), which are water soluble, toxic, and not easily biodegradable make concerns for environmental pollution worldwide. In the present study, degradation of nitrophenols-contained effluents by using laccase immobilized on the nano-porous silica beads was evaluated. 2,4-DNP was selected as the main constituent of industrial effluents containing nitrophenols. The performance of the system was characterized as a function of pH, contact time, temperature, pollutant, and mediator concentrations. The laccase-silica beads were employed in a mixed-batch reactor to determine the degradation efficiency after 12 h of enzyme treatment. The obtained data showed that the immobilized laccase degraded more than 90% of 2,4-DNP within 12 h treatment. The immobilization process improved the activity and sustainability of laccase for degradation of the pollutant. Temperatures more than 50°C reduced the enzyme activity to about 60%. However, pH and the mediator concentration could not affect the enzyme activity. The degradation kinetic was in accordance with a Michaelis-Menten equation with Vmax and Km obtained as 0.25-0.38 µmoles/min and 0.13-0.017 mM, respectively. The stability of the immobilized enzyme was maintained for more than 85% of its initial activity after 30 days. Based on the results, it can be concluded that high resistibility and reusability of immobilized laccase on CPC-silica beads make it considerable choice for wastewater treatment.