The role of ferrous ion in Fenton and photo-Fenton processes for the degradation of phenol

The efficiency of different Fenton-related oxidative processes such as Fenton, solar-Fenton and UV-Fenton were examined using phenol as a model compound in simulated and industrial wastewater. A batch study was conducted to optimize parameters like pH, hydrogen peroxide concentration and ferrous ion concentration governing the Fenton process. At optimum conditions, different Fenton-related processes were compared for the degradation of phenol. Increased degradation and mineralisation efficiency were observed in photo-Fenton processes as compared to conventional Fenton process. The maximum mineralising efficiency for phenol with Fenton, solar and UV-Fenton processes were 41%, 96% and 97% respectively. In Fenton process, carboxylic acids like acetic acid and oxalic acid were formed as end products during the degradation of phenol while in photo-Fenton processes, both these ions were identified during the early stages of phenol degradation and were oxidized almost completely at 120 min of the reaction time. In photo-Fenton processes (solar and UV light) complete degradation were observed with 0.4 mM of Fe2+ catalyst as compared to 0.8 mM of Fe2+ in conventional Fenton process. In Fenton and solar-Fenton processes, an iron reusability study was performed to minimize the amount of iron used in treatment process. The efficacy of Fenton and solar-Fenton processes was applied to effluent from phenol resin-manufacturing unit for the removal and mineralisation of phenol.     

Application of Fenton, photo-Fenton, solar photo-Fenton, and UV/H2O2 to degradation of the antineoplastic agent mitoxantrone and toxicological evaluation

In the present study, selected advanced oxidation processes (AOPs)—namely, photo-Fenton (with Fe²⁺, Fe³⁺, and potassium ferrioxalate—FeOx—as iron sources), solar photo-Fenton, Fenton, and UV/H₂O₂—were investigated for degradation of the antineoplastic drug mitoxantrone (MTX), frequently used to treat metastatic breast cancer, skin cancer, and acute leukemia. The results showed that photo-Fenton processes employing Fe(III) and FeOx and the UV/H₂O₂ process were most efficient for mineralizing MTX, with 77, 82, and 90 % of total organic carbon removal, respectively. MTX probably forms a complex with Fe(III), as demonstrated by voltammetric and spectrophotometric measurements. Spectrophotometric titrations suggested that the complex has a 2:1 Fe³⁺:MTX stoichiometric ratio and a complexation constant (K) of 1.47 × 10⁴ M^–1, indicating high MTX affinity for Fe³⁺. Complexation partially inhibits the involvement of iron ions and hence the degradation of MTX during photo-Fenton. The UV/H₂O₂ process is usually slower than the photo-Fenton process, but, in this study, the UV/H₂O₂ process proved to be more efficient due to complexing of MTX with Fe(III). The drug exhibited no cytotoxicity against NIH/3T3 mouse embryonic fibroblast cells when oxidized by UV/H₂O₂ or by UV/H₂O₂/FeOx at the concentrations tested.     

Application of UV-activated persulfate and peroxymonosulfate processes for the degradation of 1,2,3-trichlorobenzene in different water matrices

Environmental Science and Pollution Research - The presence of a large number of micropollutants in the environment, including priority and emerging substances, poses a significant risk to surface...     

Heterogeneous Fenton degradation of persistent organic pollutants using natural chalcopyrite: effect of water matrix and catalytic mechanism

Environmental Science and Pollution Research - Natural chalcopyrite was evaluated as heterogeneous Fenton catalyst. Catalytic performance was evaluated considering different systems, catalyst...     

Research on ecosystem services of water conservation and soil retention: a bibliometric analysis

Environmental Science and Pollution Research - Water conservation and soil retention are two essential regulating services that are closely related, and their relationship might produce synergies...     

Fenton and Fenton-like oxidation of pesticide acetamiprid in water samples: Kinetic study of the degradation and optimization using response surface methodology

The aims of this study were (a) to evaluate the degradation of acetamiprid with the use of Fenton reaction, (b) to investigate the effect of different concentrations of H₂O₂ and Fe²⁺, initial pH and various iron salts, on the degradation of acetamiprid and (c) to apply response surface methodology for the evaluation of degradation kinetics.     

Risk assessment of antibiotic residues in different water matrices in India: key issues and challenges

Global detection of antibiotic substances in water matrices has considerably increased in the recent past. However, in India research on this issue is limited or generalised in the literature. Risks associated with the presence of antibiotics in the environment can be quantified using a hazard quotient (HQ) approach. Here, HQs were developed using the measured environmental concentration (MEC) approach for antibiotic residues in Indian water matrices previously reported in the literature. In the present study, environmental risk assessment, using the HQ index [HQ?=?measured environmental concentration (MEC)/predicted no effect concentration (PNEC)] for different antibiotics, was performed according to the guidelines of European Medicine Evaluation Agency (EMEA). MEC and PNEC levels were obtained from the literature. PNEC values were also calculated from EC₅₀ using a safety factor when no PNECs were reported in the literature. HQs were obtained for industrial effluents (HQ?=?10⁴) that were greater than any previously reported values. Ciprofloxacin, a fluoroquinolone antibiotic, seemed to present the greatest risk in India. The HQ indices for Indian water matrices were in the following order: industrial effluents?>?lake water?>?river water?>?hospital effluents?>?treated sewage ? groundwater. A very high HQ represents a potential environmental concern for aquatic environments in India and demands that immediate attention be devoted to regulating these compounds, especially in pharmaceutical industrial wastewater.     

Comparative analysis of trace contaminants in leachates before and after a pre-oxidation using a solar photo-Fenton reaction

Sanitary landfill leachates are a complex mixture of high-strength organic and inorganic persistent contaminants, which constitute a serious environmental problem. In this study, trace contaminants present in leachates were investigated by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector before and after a pre-oxidation step using a solar photo-Fenton process. More than 40 organic compounds were detected and identified as benzene (0.09?±?0.07 mg?L^-1), trichlorophenol (TCP) (0.18?±?0.12 mg?L^-1), phthalate esters (Di-n-butyl phthalate (DBP), Butyl benzyl phthalate (BBP), Di(2-ethylhexyl) phthalate (DEHP)) (DBP: 0.47?±?0.01 mg?L^-1; BBP: 0.36?±?0.02 mg?L^-1; DEHP: 0.18?±?0.01 mg?L^-1), among others. Toluene, pentachlorophenol, dimethyl phthalate, diethyl phthalate, and Di-n-octyl phthalate were never detected in any of the samples. After the photo-Fenton treatment process, TCP decreased to levels below its detection limit, benzene concentration increased approximately three times, and DBP concentration decreased about 77 % comparatively to the raw leachate sample. The solar photo-Fenton process was considered to be very efficient for the treatment of sanitary landfill leachates, leading to the complete elimination of 24 of the detected micropollutants to levels below their respective detection limits and low to significant abatement of seven other organic compounds, thus resulting in an increase of the leachate biodegradability.     

Extraction procedures for the study of phytotoxicity and degradation processes of selected triketones in a water ecosystem

Simple and effective extraction methods based on matrix solid-phase dispersion (MSPD), dispersive liquid–liquid microextraction (DLLME), and solid-phase extraction (SPE) coupled with high-performance liquid chromatography with diode array detector (HPLC-DAD) were developed to determine triketone herbicides—sulcotrione (SUL), mesotrione (MES), tembotrione (TEMB), and their degradation products—in plant tissues and water samples. The extraction procedures were employed to enable quantification of the accumulation of selected triketone herbicides and their degradation products in a model aquatic plant, Egeria densa. To obtain comprehensive information about the triketones' influence on an aquatic plant, changes in chlorophyll concentration in plants exposed to these triketones were monitored. The average recovery ranged from 58 to 115 % (coefficients of variation 7–12 %) for plant tissues and from 52 to 96 % (coefficients of variation 8–20 %) for water samples. The limit of detection (LOD) for the MSPD–HPLC-DAD procedure was in the range of 0.06–0.23 μg/g, whereas for DLLME–HPLC-DAD and SPE–HPLC-DAD, LOD was in the range of 0.06–0.26 μg/mL. Symptoms of the phytotoxicity of sulcotrione, mesotrione, tembotrione, and their degradation products (decrease of chlorophyll concentration in plant sprouts) were observed for E. densa cultivated in water with herbicide concentrations of 100 μg/L. Moreover, the tembotrione degradation product exhibited a high level of accumulation and low metabolism in plant tissues in comparison to the other triketones and their degradation products.     

Adsorptive removal of pollutants from water using magnesium ferrite nanoadsorbent: a promising future material for water purification

Environmental Science and Pollution Research - Nanoadsorbents having large specific surface area, high pore volume with tunable pore size, affordability and easy magnetic separation gained much...     

Degradation of antidepressant pharmaceuticals by photoperoxidation in diverse water matrices: a highlight in the evaluation of acute and chronic toxicity

Environmental Science and Pollution Research - Photoperoxidation (UV/H2O2) was used to degrade three of the worldwide most consumed antidepressant pharmaceuticals—bupropion, escitalopram, and...     

Gaps,biases, and future directions in research on the impacts of anthropogenic land-use change on aquatic ecosystems: a topic-based bibliometric analysis

Environmental Science and Pollution Research - Anthropogenic land use change (ALUC) satisfies human needs but also impacts aquatic ecosystems. Aquatic ecosystems are intrinsically linked with...     

Utilization of coal fly ash in China: a mini-review on challenges and future directions

Environmental Science and Pollution Research - The rapid economic development in China places a large demand for energy, and as a result, thermal power plants in China are producing an enormous...     

Simultaneous E. coli inactivation and NOM degradation in river water via photo-Fenton process at natural pH in solar CPC reactor. A new way for enhancing solar disinfection of natural water

Bacteria inactivation and natural organic matter oxidation in river water was simultaneously conducted via photo-Fenton reaction at “natural” pH (6.5) containing 0.6 mg L⁻¹ of Fe³⁺ and 10 mg L⁻¹ of H₂O₂. The experiments were carried out by using a solar compound parabolic collector on river water previously filtered by a slow sand filtration system and voluntarily spiked with Escherichia coli. Fifty five percent of 5.3 mg L⁻¹ of dissolved organic carbon was mineralized whereas total disinfection was observed without re-growth after 24 h in the dark.     

欧氏贴近度模糊物元分析法优选制浆造纸中段水处理工艺

制浆造纸中段水处理工艺优选属于多方案、多指标的综合评价问题,本研究在模糊物元分析的基础上,结合优选理论中贴近度的概念,建立了制浆造纸中段水处理工艺优选的欧氏贴近度模糊物元分析法(FMEA),并通过均方差法确定指标权重.通过建立评价指标体系,从技术性能、经济费用和管理效果3个方面对传统活性污泥法、完全混合活性污泥法、氧化沟法和序批式活性污泥法(SBR)进行评价,结果表明,SBR法技术性能和经济费用最优,氧化沟法管理效果和综合评价最优,为不同条件下优选制浆造纸中段水处理工艺提供了参考依据.     

Improved concepts and methods in analysis and evaluation of the urban climate for optimizing urban planning processes

Planning processes are strongly influenced by an increased awareness of environmental issues concerned by projected land-use transformations. A research project was carried out to produce climate maps for the region of Basel/Switzerland to enable planning authorities taking care of the urban climate and its interrelations with urban structures. Main focus was given to develop and implement a methodology meeting not only the regional requirements of Basel. The new approach is not depending on subjective criteria or manual interventions and ensures its applicability for other regions. Three basic concepts were developed or improved in this study. A new definition of `climatopes’ was introduced, and methods were developed for their digital determination by objective criteria. This definition of climatopes requires adequate information on land-use, which is provided by introducing the concept of `areal types'. In contrast to `traditional’ land-use classes directly derived from satellite images, areal types are complex aggregates reflecting not only different physical surface properties, but also socioeconomic aspects of land-use. `Ventilation classes’ are the second component required to delineate climatopes. They summarize the combined influencing factors of terrain features and land-use structures on wind field and urban ventilation. Their determination is based on topographic information and surface properties derived from a digital terrain model and from land-use data. The spatial distribution of climatopes was computed for Basel. Various quality assessment procedures and the application of climatopes for an automated generation of planning guidelines demonstrate the applicability of the concepts. Climate maps containing the results of the analysis and evaluation of the urban climate of Basel were estimated by the involved planners to be a valuable tool meeting their practical requirements to a high degree.     

Farmer knowledge and a priori risk analysis: pre-release evaluation of genetically modified Roundup Ready wheat across the Canadian prairies

Background, aim, and scope  

The controversy over the world’s first genetically modified (GM) wheat, Roundup Ready wheat (RRW), challenged the efficacy of ‘science-based’ risk assessment, largely because it excluded the public, particularly farmers, from meaningful input. Risk analysis, in contrast, is broader in orientation as it incorporates scientific data as well as socioeconomic, ethical, and legal concerns, and considers expert and lay input in decision-making. Local knowledge (LK) of farmers is experience-based and represents a rich and reliable source of information regarding the impacts associated with agricultural technology, thereby complementing the scientific data normally used in risk assessment. The overall goal of this study was to explore the role of farmer LK in the a priori risk analysis of RRW.     

Photolytic degradation of methyl-parathion and fenitrothion in ice and water: Implications for cold environments

Here we investigate the photodegradation of structurally similar organophosphorus pesticides; methyl-parathion and fenitrothion in water (20 °C) and ice (−15 °C) under environmentally-relevant conditions with the aim of comparing these laboratory findings to limited field observations. Both compounds were found to be photolyzed more efficiently in ice than in aqueous solutions, with quantum yields of degradation being higher in ice than in water (fenitrothion > methyl-parathion). This rather surprising observation was attributed to the concentration effect caused by freezing the aqueous solutions. The major phototransformation products included the corresponding oxons (methyl-paraoxon and fenitroxon) and the nitrophenols (3-methyl-nitrophenol and nitrophenol) in both irradiated water and ice samples. The presence of oxons in ice following irradiation, demonstrates an additional formation mechanism of these toxicologically relevant compounds in cold environments, although further photodegradation of oxons in ice indicates that photochemistry of OPs might be an environmentally important sink in cold environments.     

Presence of heavy metals in drinking water resources of Iran: a systematic review and meta-analysis

Environmental Science and Pollution Research - Water quality is one of the most important indices for public health especially for drinking water consumptions. This study was conducted to survey...