The persistent organic pollutants (POPs) are environmentally stable and highly toxic chemicals that accumulate in living adipose tissue and have a very destructive effect on aquatic ecosystems. To ...analyze the evolution of the concentration and prevalence of POPs such as α-HCH, β-HCH, γ-HCH, ∑-HCH, Heptachlor, Aldrin, p,p′-DDE, p,p′-DDT, ∑-DDT, and ∑-OCP in water resources, a search between January 01, 1970, to February 10, 2020, was followed using a systematic review and meta-analysis prevalence. Among the 2306 explored articles in the reconnaissance step, 311 articles with 5315 exemplars, 56 countries, and 4 types of water were included in the meta-analysis study. Among all studied POPs, the concentration of p,p′-DDT in water resources was the highest, especially in drinking water resources. The overall rank order based on the concentration and prevalence of POPs were surface water > drinking water > seawater > groundwater. To identify POPs-contaminated areas, the distance from the mean relative to their distribution was considered. The most to the least polluted areas included: South Africa, India, Turkey, Pakistan, Canada, Hong Kong, and China. The highest carcinogenic risk was observed for β-HCH (Turkey and China), followed by α-HCH (Mexico). The highest non-carcinogenic risk was identified for Aldrin (all analyzed countries), followed by Dieldrin (Turkey) and γ-HCH (Mexico). The Monte Carlo analysis (under the assumption that γ-HCH has a normal distribution), the mean obtained was 8.22E−07 for children and 3.83E−07 for adults. This is in accordance with the standard risk assessment approach. In terms of percentiles, the Monte-Carlo approach indicates that 75% of child population is under the 1.07E−06 risk and 95% of adults under 7.35E−06.
Health risk assessment of POPs in water resources worldwide. Display omitted
•p,p′-DDT concentration in water resources is higher than other POPs.•South Africa is the most polluted region.•China, Mexico, and Turkey are exposed to adverse POPs risk in the water resources.•The order of POPs is surface water > drinking water > seawater > groundwater.•In the Monte Carlo model, the mean is 8.22E−07 for children and 3.83E−07 for adults.
Phthalate esters (PAEs) are known as esters of phthalic acid, which are commonly used as plasticizers in the plastic industry. Due to the lack of chemical bonding with the polymer matrix, these ...compounds are easily separated from plastic products and enter the environment. To investigate the growth of concentration of PAEs like DBP (Dibutyl phthalate), DEP (Diethyl phthalate), DMP (Dimethyl phthalate), DIBP (Diisobutyl phthalate), and TPMBP (tris(2-methylbutyl) phosphate) in different water sources, a study from January 01, 1976, to April 30, 2021, was implemented via a global systematic review plus meta-analysis in which, 109 articles comprising 4061 samples, 4 water types, and 27 countries were included. Between various types of water sources, river water and lake water were the most contaminated resources with PAEs. Among all studies of PAEs, DBP and DEP with the values >15,573 mg L−1 have the highest average concentration and TPMBP with the value 0.002885 mg L−1 has the lowest average concentration in water sources. The most contaminated water sources with PAEs were in Nigeria and the least contaminated was in China. Besides, Monte-Carlo simulation indicated that for DMP and DEP minimum values that are lower than the acceptable limit are generated. However, most of the population (>75 %) is at risk for both adults and child cases. For DIBP and DBP the situation is much worse, the simulations not providing at least one case where the R index is lower than the acceptable limit of 1E-06.
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•Here we provide a global meta-analysis and risk assessment of PFAE in drinking water.•River and lakes are the most contaminated aquatic systems.•DBP shows the highest and BBP the lowest Z scores reflecting concentration differences.•Nigeria and China are the lowest and highest polluted regions, respectively.•More than 75 % of adults and children China is at risk for health effects.
Pesticides are chemical compounds used to kill pests and weeds. Due to their nature, pesticides are potentially toxic to many organisms, including humans. Among the various methods used to ...decontaminate pesticides from the environment, the heterogeneous photocatalytic process is one of the most effective approaches. This study focuses on artificial intelligence (AI) techniques used to generate optimum predictive models for pesticide decontamination processes using heterogeneous photocatalytic processes. In the present study, 537 valid cases from 45 articles from January 2000 to April 2020 were filtered based on their content collected and analyzed. Based on cross-industry standard process (CRISP) methodology, a set of four classifiers were applied: Decision Trees (DT), Bayesian Network (BN), Support Vector Machines (SVM), and Feed Forward Multilayer Perceptron Neural Networks (MLP). To compare the accuracy of the selected algorithms, accuracy, and sensitivity criteria were applied. After the final analysis, the DT classification algorithm with seven factors of prediction, the accuracy of 91.06%, and sensitivity of 80.32% was selected as the optimal predictor model.
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•Heterogeneous photocatalytic processes for pesticide decontamination were analyzed.•Database containing 537 instances from 45 articles was constructed.•Data were modeled by classification algorithms of DT, BN, SVM, and MLP.•DT classification algorithm was selected as optimal predictor model.•Effective variables and relationships between them were identified.
Acute exposure to trace metals (TMs) in water is hazardous to human health. The average concentrations (Cavg.) and carcinogenic (CAR) and non-carcinogenic (non-CAR) risks of eight TMs to World Health ...Organization's (WHO) guidelines and national standard limits (NSLs)were determined. The Cavg. and (the range) of As, Hg, Cd, Pb, Co, Cr, Ni, and Zn were measured as 4.29 ± 0.57 μg L−1 (1.12–10.27 μg L−1), 0.22 ± 0.10 μg L−1 (ND-1.05 μg L−1), 0.31 ± 0.18 μg L−1 (ND-1.80 μg L−1), 4.66 ± 0.32 μg L−1 (0.10–14.22 μg L−1), 24.61 ± 4.65 μg L−1 (3.11–67.25 μg L−1), 16.86 ± 5.54 μg L−1 (5.12–34.61 μg L−1), 14.07 ± 4.37 μg L−1 (3.79–31.39 μg L−1), and 268.42 ± 75.82 (87.29–561.22 μg L−1), respectively. The Cavg. of Co and Hg exceeded the WHO and NSLs. The non-CAR risk assessment was used to order the TMs according to the total target hazard quotient (TTHQ) As > Pb > Cr > Co > Zn > Hg > Ni > Cd. None of the investigated age groups are at risk As there is a low Cavg of all trace metals (i.e., the THQ is > 1). The age groups were ranked based on THQ and incremental lifetime cancer risk (ILCR) As < 1 year, >1–10 years, > 11–19 years, and > + 20 years. The ILCR of As for all the age groups was >10−4, whereas for Pb it was <10−6. Cumulative carcinogenic risk (CCR) for As and Pb was at a safe threshold risk (>10−4) for all the age groups.
•Exposure to trace metals can endanger the health of populations.•Concentrations of trace metals in Kermanshah city, Iran tap water were determined.•The concentration of different trace metals exceeded the standard limits.•The ILCR was ranked as based on age as < 1 yr> 1–10 yrs > + 20 yrs > 11–19 yrs.•Trace metals threshold risk can correlate concentration limit in drinking water.
This study focuses on modeling the mass transfer process in the vacuum membrane distillation method (commonly used for radioactive wastewater) by means of artificial neural networks (ANNs). For this ...purpose, the permeate flux is modeled as a function of four system parameters (pollutant type, feed temperature, permeate temperature, and permeate pressure). To determine the best suitable model for the considered system, several structures of ANNs were analyzed. The results obtained indicated that a feed forward multilayer perceptron neural networks with a hidden layer and ten neurons in hidden layer and with determination of coefficient of 0.975 and maximum root mean squared error of 1.83% can predict the permeate flux with desirable accuracy.
Due to its cytotoxic effect, metronidazole (MNZ) is a drug commonly used to treat bacterial, protozoal, and microaerophilic bacterial infections. After consumption, it undergoes a series of ...metamorphic reactions that lead to the degradation of oxidized, acetylated, and hydrolyzed metabolites in the environment. To eliminate such pollutants, due to their high potential, adsorption and photocatalysis extensive processes are used in which graphene can be used to improve efficiency. This review analyses the use of graphene as an absorbent and catalyst with a focus on absorption and photocatalytic degradation of MNZ by graphene-based materials (GBMs). The parameters affecting the adsorption, and photocatalytic degradation of MNZ are investigated and discussed. Besides, the basic mechanisms occurring in these processes are summarized and analyzed. This work provides a theoretical framework that can direct future research in the field of MNZ removal from aqueous solutions.
•Metamorphic reactions of metronidazole (MNZ) in environment hydrolyzed metabolites.•Adsorption and photo catalysis coupled with graphene can eliminates MZN effect.•MZN adsorption is influenced by its concentration and GBMs properties.•GO with highly dispersion polarized surface allows higher MNZ removals.
AbstractIn this study, the advanced oxidation process for dye removal from textile wastewater treatment was investigated by means of an experimental setup in which the effect of several parameters on ...dye removal efficiency peroxydisulfate concentration, ultraviolet (UV) irradiation, temperature, dye concentration, and time was examined. In order to predict the removal efficiency, two types of artificial neural networks were used: an adaptive neuro-fuzzy inference system (ANFIS) and an artificial neural network determined with differential evolution called hybrid self-adaptive differential evolution with neural networks (hSADE-NN). After the successful development of ANFIS, its ability to predict test data was checked. Also, a series of models of the process was determined with hSADE-NN. Comparison of the two approaches indicates that both methods provide good results, the average absolute relative error for hSADE-NN being 3.61% and that for ANFIS 5.18%. After that, a process optimization was performed, the scope being to determine the conditions for maximum dye removal efficiency under various constraints, considered as a means to reduce resources consumed.
Electrode stability, lifetime and electrochemical oxidation.▪
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•Comprehensive and state-of-the-art information on the stability and service life of electrodes are provided.•The ...degradation mechanisms of pollutants on different EAOPs electrodes were discussed.•Electrodes composed of intermediate compounds have a higher lifetime than binary oxides.•The coating of electrodes with noble metals usually improves stability.
In recent years, novel advanced oxidation processes (AOPs) based on electrochemical technology known as electrochemical advanced oxidation processes (EAOPs) have been applied to the degradation of a wide range of persistent organic pollutants (POPs). EAOPs produce in situ hydroxyl radicals (•OH) capable of degrading POPs and their mineralization by producing stable electrode materials (e.g., boron-doped diamond (BDD), doped-SnO2, PbO2, and substoichiometric- and doped-TiO2). Moreover, ozone and sulfate radicals could be produced, based on electrolyte type, which cause the degradation of POPs. Although EAOPs are promising novel technologies, various parameters related to the types of electrodes in the POPs oxidation have not been fully addressed. In order to provide a full and comprehensive picture of the current state of the art, and improve the treatment efficiency and motivate new researches in these areas, this study analyzed the research covering EAOPs aspects, with a focus on the comparison of stability, lifetime and service life of electrodes. Electro-chemical stability and longer life are the major concerns in the EAOPs. Since electrodes must be highly efficient for long periods of time, the determination of their lifetime is essential. On the other hand, in real-life situations, lifetime determination is difficult. The oxidation ability and durability of electrodes during the reactions depended on the structural properties of them. Electrodes composed of intermediate compounds had a higher lifetime than binary oxides. Another factor affecting the stability of the electrodes was the structure of the expanded mesh style anodes to better control the bubble growth through a polygonized structure. Anodes with irregular shapes at the surface were more likely to discharge the bubbles and reduce the negative effects of the high pressure on the surface of the electrode. The electrodes having high oxidation strength and stability, had a shorter service life value. Furthermore, the calcination temperature and the amount of applied current directly affected the lifetime of the electrodes. On the other hand, the electrical resistance of the synthesized electrode was effective in the lifetime. Coating of electrodes with noble metals such as tantalum, titanium, niobium, zirconium, hafnium, vanadium, molybdate and tungsten improved the electrode stability.
This study evaluates the degradation efficiency of Malathion using Fenton (Fe2+/H2O2: F), photo-Fenton (UV/Fe2+/H2O2: PF), and sono-photo Fenton (US/UV/Fe2+/H2O2: SPF) processes as well as determines ...the toxicity of the byproducts of degradation. The effect of various operational parameters on the Malathion degradation rate, including pH, Fe2+ concentration, Malathion concentration, and H2O2 were studied. The removal efficiency was determined to be 98.79% for the SPF, > 70.92% for the PF, and > 55.94% for the F processes under the following optimal conditions: pH = 3, H2O20 = 700 mg/L, Fe2+0 = 20 mg/L, and Malathion0 = 20 mg/L. The operating costs (USD/kgMalathion-removed) were acquired as SPF > PF > F. Moreover, Malaoxon, diethyl maleate, diethyl malate, ethyl 2-hydroxysuccinate, and D-malate were among the detected byproducts from the Malathion degradation in the SPF process. Both the non-carcinogenic risk and the carcinogenic risk were assessed to establish the quality of the effluent from all three processes. The toxicity of the treated effluents, determined by Vibrio fischeri luminescence, indicated that the toxicity depends on the selected treatment process. The high degradation efficiency of the Fenton-based processes is not equivalent to achieving detoxification of the effluents. As such, the SPF process was determined to be the most effective for the Malathion degradation, total organic carbon (TOC) removal, and health risk assessment.
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•Effective Malathion degradations were achieved by F, PF and SPF processes.•SPF process demonstrated higher Malathion degradation than other processes.•Five degradation byproducts were identifies within the possible oxidation mechanism.•Toxicity of Malathion was evaluated by bioluminescence and AChE inhibition assay.•The carcinogenic risk (CR) and non- CR after-treatment were in the tolerable limits.
•The application of nanocatalysts for converting biomass to biofuels was presented.•Conventional technologies for the conversion of biomass to biofuel were reviewed.•The nanocatalytic routes for ...biomass conversion to combustible mixtures were reviewed.•The future outlooks and present challenges were examined.
In the latest decade, the energy requirements have raised, the fact that directly influenced the increase in fossil fuel consumption. Taking into account the pollution problems associated with fossil fuels, biomass resources come as a promising alternative energy source. The biomass to biofuel conversion can be achieved through strategies such as thermochemical (gasification and direct liquefaction) or biological processes. Moreover, catalytic approaches are increasingly used for biofuel production. In this context, the role of nanocatalysts becomes crucial when considering product quality and optimal operating conditions. Novel nanocatalysts with advanced properties can reduce the most common problems encountered in heterogeneous catalysts: unproductiveness, resistance to mass transfer, time-intensive, rapid deactivation. Consequently, the development of new types of nanocatalysts registered a rising trend. This work focuses on biofuels and tackles a series of aspects such as classification, production technologies, and strategies for yield increase in the context nanocatalysts use. Finally, the future outlooks and challenges of biomass conversion processes to biofuels using nanocatalysts were examined.
