Environmental impact assessment of dicationic ionic liquids with ammonium-phosphonium cations and amino acid anions.

Progress in the development of biodegradable or biobased ionic liquids (ILs) has led to the design of green compounds for several applications. Herein, four biocompatible dicationic ionic liquids (DILs) with ammonium-phosphonium cations and amino acid anions were synthesized and investigated their environmental impact. The structures of the DILs were confirmed by spectral analyses (1H, 13C and 31P NMR). Furthermore, physicochemical properties such as density, viscosity and refractive index were determined. Water content, bromide content and solubility were thereafter determined as the parameters needed for further studies. Subsequently, their antifeedant activity towards economically important pests of grain in storage warehouses: the granary weevil, the confused flour beetle, and the khapra beetle was examined, showing the dependence on structure. Moreover, selected DILs were investigated for toxicity towards white mustard, Daphnia magna, and Artemia franciscana to specify the environmental impact. These studies were complemented by understand the biodegradation of DILs by bacterial communities derived from soil at the agricultural land. The result was DILs with limited environmental footprints that have great potential for further application studies.

Life cycle assessment and life cycle cost analysis of anion exchange and granular activated carbon systems for remediation of groundwater contaminated by per- and polyfluoroalkyl substances (PFASs).

Anion exchange resin (AER) and granular activated carbon (GAC) have emerged as prominent technologies for treatment of waters contaminated with per- and polyfluoroalkyl substances (PFASs). This study compares the life cycle environmental impacts and life cycle costs of remediating PFAS-contaminated groundwater with these competing technologies, using field pilot data to inform model inputs. Comparative analysis indicates that AER systems employing single-use "PFAS-selective" resins have lower environmental impacts and costs than systems using regenerable resins or GAC adsorbents, supporting its use in future remediation efforts. Use of GAC operated as a single-use adsorbent led to the highest emissions as well as the highest treatment costs, with thermally-reactivated GAC proving to be less impactful than regenerable AER treatment. Sensitivity analyses highlighted the dominance of media usage rate (MUR), which is highly dependent on the selected PFAS treatment goals, to determine environmental impacts and costs over a 30-year system life cycle. Selection of very stringent changeout criteria (e.g., detection of any PFASs in effluent) significantly reduces the advantages of single-use resins. For regenerable AER, environmental impacts were dominated by management of the PFAS-contaminated brine/co-solvent waste stream used to regenerate the adsorbent, as well as the cosolvent content of the regenerant mixture and the cosolvent recovery efficiency achieved via on-site distillation. High impacts estimated for GAC adsorption, the result of high MUR relative to ion exchange media, can be significantly reduced if spent adsorbents are reused after thermal reactivation, but impacts are still greater than those predicted for single-use ion exchange systems. Findings are expected to hold across a range of diverse sites, including drinking water systems treating more dilute sources of PFAS contamination, as PFAS breakthrough was not found to be highly sensitive to sourcewater PFAS concentrations.

Assessment of groundwater geochemistry for drinking and irrigation suitability in Jaunpur district of Uttar Pradesh using GIS-based statistical inference.

The quality of groundwater in the Jaunpur district of Uttar Pradesh is poorly studied despite the fact that it is the only supply of water for both drinking and irrigation and people use it without any pre-treatment. The evaluation of groundwater quality and suitability for drinking and irrigation is presented in this study. Groundwater samples were collected and analysed by standard neutralisation and atomic emission spectrophotometry for major anions (HCO3-, SO42-, Cl-, F-, NO3-), cations (Ca2+, Mg2+, Na+, K+), and heavy metals (Cd, Mn, Zn, Cu, and Pb). The geographic information system (GIS) and statistical inferences were utilised for the spatial mapping of the groundwater's parameters. The potential water abstraction (i.e. taking water from sources such as rivers, streams, canals, and underground) for irrigation was assessed using the sodium absorption ratio (SAR), permeability index (PI), residual sodium carbonate (RSC), and Na percentage. According to the findings, the majority of the samples had higher EC, TDS, and TH levels, indicating that they should be avoided for drinking and irrigation. The positive correlation coefficient between chemical variability shows that the water chemistry of the studied region is influenced by geochemical and biological causes. According to the USSL (United States Salinity Laboratory) diagram, most of the samples fall under the C2-S1 and C3-S1 moderate to high salt categories. Some groundwater samples were classified as C4-S3 class which is unfit for irrigation and drinking. This study suggests that the groundwater in the study area is unfit for drinking without treatment. However, the majority of the samples were suitable for irrigation.

Neural network and decision tree-based machine learning tools to analyse the anion-responsive behaviours of emissive Ru(II)-terpyridine complexes.

We implemented both neural network and decision tree-based machine learning tools to analyse the anion-responsive behaviours of two heteroleptic Ru(II) complexes based on two tridentate ligands, 2,6-bis(benzimidazole-2-yl)pyridine (H2pbbzim) and substituted terpyridine ligands, tpy-Ar with Ar = 2-naphthyl and 9-anthryl groups. The secondary coordination sphere of the complexes is decorated with two imidazole NH moieties, benefitting from the anion sensing characteristics of the complexes previously reported by us. Considerable change in their absorption, emission as well as electrochemical and spectroelectrochemical responses occur in the presence of selected anions. Restoration of their initial states is made possible by acid and the process is reversible. We utilized their spectral, electrochemical and spectroelectrochemical responses upon the influence of anions and acid to mimic the operations of YES-NOT and set-reset flip-flop logic gates. We also implemented machine learning tools such as artificial neural networks (ANNs), adaptive neuro-fuzzy inference system (ANFIS) and decision tree (DT) regression to analyse and forecast the experimental data and can thus reduce the time and expenditure associated with the execution of comprehensive sensing experiments. The outcomes of the ANN, ANFIS and DT methods were also tallied with the experimental results. Among the three models, the outcomes derived from DT regression analysis turned out to be excellent with almost zero error. Thus, the applied machine learning based tools could be regarded as a prospective anion-responsive data model for the studied complexes.

Comparative assessment of groundwater quality indices of Kannur District, Kerala, India using multivariate statistical approaches and GIS.

The aim of the study was to determine the groundwater characteristics of rural and industrial zones in the Kannur region. In 2011, 25 groundwater data were collected from the centre for water resource development management (CWRDM), and in 2019, 25 groundwater samples from rural and near-industrial areas were collected and analysed for major anions (HCO3-, CO32-, Cl-, NO3- and SO42-), and cations (TH, Ca2+, Mg2+, Na+, K+ and Fe2+) using APHA standards. To better understand the link between water quality parameters, multivariate statistical analysis approaches such as principal component analysis (PCA), hierarchical cluster analysis (HCA), correlation matrix analysis (CMA), and Pearson correlation bivariate one-tailed analysis (PCBOTA) were used to analyse the inter-relationship of data. The Inverse Distance Weighed (IDW) method was used to generate the spatial distribution of the groundwater quality index (GWQI). In 2011, the water quality index (WQI) value of groundwater samples was excellent at 24.42% and good at 54.14%, which were used for drinking purposes and moderate at 17.22% and poor at 4.22% for irrigation purposes in this study area. In 2019, excellent 21.62%, good 51.56% were used for drinking purpose, and moderate at 18.14%, and poor at 8.68% for irrigation purposes. By comparing the data with BIS and WHO standards, it is clear that groundwater in Kannur district is of good quality. In groundwater samples, the PCA eigen values were reported in 2011 (84.7%) and 2019 (73.4%) for statistical approaches. This study uses HCA and PCBOTA to analyse the elements, resulting in a better understanding of groundwater quality development. GIS based WQI maps were obtained and utilised to gain a better knowledge of the study area's past and present water quality status. We observed that the quality of groundwater in the study region's north-western portion is insufficient for drinking water.

Assessment of Ismailia Canal for irrigation purposes by water quality indices.

Ismailia Canal is one of the significant streams of the Nile River in Egypt. The study aimed to determine the water quality of Ismailia Canal based on the regional and seasonal variability of physicochemical parameters, irrigation criteria, and the irrigation water quality index (IWQI). It was observed that the physicochemical parameters were within the acceptable FAO irrigation limits. All cations and anions values were within the acceptable FAO limits for irrigation, except the potassium (K+) concentrations were over the permissible irrigation limits. The one-way analysis of variance (ANOVA) suggested a significant seasonal variation in the canal's water quality concerning all parameters (p value ˂ 0.05). However, the regional variation among various sites was statistically insignificant (p value > 0.05). Statistical analysis was used to calculate the correlation coefficient between different parameters, and the study showed highly significant correlation coefficients between different pairs of water quality parameters. The correlation matrix showed that the pH significantly affected IWQI (r = 0.661). The irrigation criterion values for Ismailia Canal were good, and the WQI levels for irrigation utilization at all studied sites were satisfactory. Deterioration of water quality may occur due to industrial, municipal, and agricultural activities. Drainage water should be treated before being mixed with irrigation water to improve its suitability for irrigation.

High performance anion exchange chromatographic and colorimetric methods for quality assessment of total and free polysaccharide content in Haemophilus influenzae type b conjugate vaccine containing lactose.

The presence of lactose as a stabilizer in Haemophilus influenzae type b (Hib) conjugate vaccine is a challenge for chromatographic resolution of its total and free poly ribosyl ribitol phosphate (PRP) content. Sample pretreatment using ultrafiltration was performed and had removed ≥95% of lactose in shorter time compared to the conventional dialysis process. Separation of free unconjugated PRP was performed using solid-phase extraction C4 cartridges. Hib conjugate vaccine was then analyzed for determination of total and free PRP, using two validated techniques: high performance anion exchange chromatography with pulsed amperometry (HPAEC-PAD) for ribitol determination and a colorimetric assay for phosphorus determination. Lactose removal had enabled a rapid chromatographic assay via fast depolymerization of PRP using high temperature treatment. Modifying the burning process in the colorimetric assay reduced the analysis time significantly compared to the pharmacopoeial method. Linearity was obtained over the range of 0.10-10.0 µg mL-1 for the HPAEC method and in the range of 1.0-8.0 µg mL-1 for the colorimetric one. Stability of Hib conjugate vaccine was investigated. The HPAEC results revealed about a 35% increase in free PRP content after storage under stressed conditions (moisture and temperature). The proposed methods offered a reliable and economic platform for assessing the immunogenicity, efficacy and stability of Hib conjugate vaccine containing lactose for the biopharmaceutical industry.

Determination of the geographic origin of 52 honey samples based on the assessment of anionic content profiling with a new algorithm using monolithic column-based micellar nano-liquid chromatography.

In the present study, a new micellar nano LC-UV was, for the first time, reported for the separation and determination of five anions (chloride, nitrite, bromide, sulfate and nitrate) in 52 honey samples. Based on this approach, a graphene oxide-based monolithic column was prepared and applied for the samples. Various amounts of hexadecyltrimethyl-ammonium bromide (HTAB) in the mobile phase were used in order to optimize the separation conditions. The baseline separation was achieved using mobile phase with 25/75% (v/v) ACN/10 mM phosphate buffer at pH 3.4, while the amount of HTAB was optimized as 0.22 mM in the mobile phase. The whole method was validated and it leads to high sensitivity. The LOD values were found in the range of 0.02-0.22 µg/kg, while LOQ values were found in the range of 0.06-0.18 µg/kg. The method allowed to achieve sensitivity analyses of anionic content in 52 honey samples. All data were evaluated using a new algorithm for geographic origin discrimination. K-nearest neighbor algorithm (K-NN), cubic support vector classifier (K-DVS), and K-Mean cluster analysis were used for geographic origin discrimination of honeys. The accuracy of the whole model was calculated as 94.4% with the K-DVS method. The samples from five provinces were classified 100% correctly, while two of them were classified with one misclassification, with an accuracy of 89.9% and 83.3%, respectively. PRACTICAL APPLICATION: The new platforms and advanced technologies are crucial for advanced food analysis. In this article, a novel methodology was attempted for the determination of geographic origin of 52 honey samples. In this sense, micellar nano LC technique with a homemade monolithic nano-column was, for the first time, applied for the anion analysis using a new algorithm.

11C-Labeled Radiotracer for Noninvasive and Quantitative Assessment of the Thiocyanate Efflux System in the Brain.

Thiocyanate (SCN-) alters the potency of certain agonists for the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, and dysfunctions in AMPA receptor signaling are considered to underlie a number of neurological diseases. While humans may be exposed to SCN- from the environment, including food sources, a carrier-mediated system transports SCN- from the brain into the blood and is an important regulator of SCN- distribution in the central nervous system. The assessment of this SCN- efflux system in the brain would thus be useful for understanding the mechanisms underlying the neurotoxicity of SCN- and for elucidating the relationship between the efflux system and brain diseases. However, the currently available technique for studying SCN- efflux is severely limited by its invasiveness. Here, we describe the development of a SCN- protracer, 9-pentyl-6-[11C]thiocyanatopurine ([11C]1), to overcome this limitation. [11C]1 was synthesized by the reaction of the iodo-precursor and [11C]SCN- or the reaction of the disulfide precursor with [11C]NH4CN. The protracer [11C]1 entered the brain after intravenous injection into mice and was rapidly metabolized to [11C]SCN-, which was then eliminated from the brain. The efflux of [11C]SCN- was dose-dependently inhibited by perchlorate, a monovalent anion, and the highest dose caused an 82% reduction in the efflux rate. Our findings demonstrate that [11C]1 can be used for the noninvasive and quantitative assessment of the SCN- efflux system in the brain.

Novel fabricated low-cost hybrid polyacrylonitrile/polyvinylpyrrolidone coated polyurethane foam (PAN/PVP@PUF) membrane for the decolorization of cationic and anionic dyes.

Dyes are recalcitrait organic pollutants threatening the aquatic environment and human health. In the present study, a novel low-cost hybrid membrane was fabricated by coating polyurethane foam (PUF) with polyacrylonitrile/polyvinylpyrrolidone (PAN/PVP) via phase inversion technique from casting solutions consisting of PAN and PVP with Dimethyl formamide (DMF) and applied for removal of cationic (Methylene Blue (MB)) and anionic (Methyl Orange (MO)) dyes from aqueous solutions. The as-prepared membrane was first characterized by Scan Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Energy Dispersive Spectrometry (EDS), etc. Then, batch experiments were conducted to optimize the adsorption conditions, including contact time, adsorbent dose, dyes concentration, and pH. The dye removal results fitted with pseudo first and second-order kinetics; Langmuir, Freundlich, and Temkin isotherms' models. The maximum dye decolorization was approximately 97% and 95% within 60 and 120 min using 0.5 and 1 g of the fabricated composite for MB and MO, respectively. The kinetic studies showed rapid sorption dynamics following a second-order kinetic model. In addition, dye adsorption equilibrium data fitted well to the Freundlich isotherm with monolayer maximum adsorption capacity of 6.356 and 3.321 mg/g for MO and MB dye, respectively. Thus, the novel hybrid membrane is promising as a cheap and efficient adsorbent for the removal of both cationic and anionic dyes from wastewater. The current study demonstrated a new avenue to achieve efficient management of dyes in aquatic environments.

Photoredox-Catalyzed Oxidation of Anions for the Atom-Economical Hydro-, Amido-, and Dialkylation of Alkenes.

Photoredox catalysis has become a powerful method to generate free radical intermediates in organic synthesis. This report describes the use of photoredox catalysis to directly oxidize common nucleophilic anions to access electrophilic 1,3-dicarbonyl and amidyl radical intermediates. First, conjugate bases of 1,3-dicarbonyls were oxidized to neutral radical species for intramolecular hydro- and dialkylation of alkenes. This overall redox-neutral process provided cyclopentanone products in excellent yields (up to 96%). The scope included a variety of styrene radical acceptors and products with newly formed vicinal quaternary carbons. This process was then extended to the synthesis of pyrrolidinones by alkene amidoalkylation that proceeded via N-aryl amidyl radical intermediates in good yield (up to 85%). These reactions were characterized by their mild conditions, high atom economy, and the absence of stoichiometric byproducts. Mechanistic and computational studies supported a stepwise proton-coupled electron transfer mechanism, where an "electron borrowing" photocatalyst oxidizes an anion and reduces a benzylic radical after bond formation.

Chemical and microbiological assessment of drinking water quality.

Background: Access to an adequate amount of water is restricted because of the increase in the use of natural resources, which is caused by the rapid growing in world population and the climate change that global warming brings, and the development in the industry. Investigating the causes of water pollution, creating solutions for the problem, taking the control of the pollution, and maintaining monitorability are necessary. Objectives: This study was carried out in order to determine microbiological and chemical characteristics of drinking water and their compatibility for human consumption with the aim of providing safety of drinking waters. Methods: Thirty-four drinking water samples obtained from different sampling points in Ankara, Turkey, in 2019 were subjected to microbiological analysis and chemical analysis in terms of anions (bromide-Br-, chloride-Cl-, fluoride-F-, nitrate-NO3-, nitrite-NO2-, sulfate-SO4-2) by ion chromatography. Microbiological analyses were applied according to the international standards. Results: None of the samples contained coliform bacteria, Escherichia coli and intestinal enterococci. It was established that concentrations of the specified anions in tested waters were within the acceptable levels of with the Council Directive 98/83/EC. Conclusions: The determined chemical and microbiological qualities of these samples are suitable for drinking, and do not pose any threats to public health.

Influence of anions on ozonation of bisphenol AF: Kinetics, reaction pathways, and toxicity assessment.

In this article, the degradation of 4, 4'-(hexafluoroisopropylidene) diphenol (bisphenol AF, BPAF) by ozone was studied and toxicity of the degradation products was evaluated. Kinetic studies showed that acidic conditions were more conducive to the ozone degradation of BPAF than alkaline conditions. In the presence of common anions, Br- and SO42- promoted the degradation of BPAF, whereas NO2-, NO3-, HSO3- inhibited the degradation, and the other anions and cations had no significant effect. The degradation products were analyzed by mass spectrometry, and were mainly manifested in hydroxylation, carboxylation and cleavage of benzene ring. The addition of NO2-, HSO3- and Br-produced the corresponding free radicals, resulting in the parent compound being attacked and affecting the degradation efficiency and pathways. The theoretical calculated results showed that the ortho-site of the BPAF phenolic hydroxyl group was more active than the meta-position, and it's more likely for free radicals to attack ortho-sites and initiate substitution reactions. Toxicity assessment of the products in the process of ozone degradation showed that toxicity of the products was reduced by benzene ring cleavage and a reduction in the F atomic number. However, the toxicity of nitro and brominated products of BPAF was increased. These findings provide some new insights into the role of common ions in ozonation process and product formation, and supplement the existing conclusions. The results of this study remind future researchers to concern that inorganic ions in real water may be converted into corresponding free radicals that affect the formation of ozone oxidation products.

Human health risk assessment of metals and anions in surface water from a mineral coal region in Brazil.

Coal mining releases high concentration elements to the environment, which can be deposited in surface water, causing several human health problems. Candiota mine in the south of Brazil is the largest coal reserves in the country, representing approximately 40% of total national coal reserves. Therefore, the present study aimed to estimate the chronic daily dose and the non-carcinogenic risk index for metals and anions in surface waters of Candiota Region, using the USEPA protocols for Human Health Risk Assessment. A total of eight water samples were collected over a distance of up to 15 km from the emission sources of the thermal power generation companies, then the Chronic Daily Intake (CDI), Hazard Quotient (HQ), Hazard Index (HI), and sum of Hazard Index (ΣHI) were calculated. All the elements and anions evaluated showed natural concentrations for continental fresh waters according to Brazilian legislation, except Pb. Individually, none of the metals Pb, As, Cd, Ni, and Se or anions F- and NO3- showed an HI value greater than 1. However, the sum of HI (ΣHI) (five metals and two anions) by sample point showed values close to 1, for one of the eight points analyzed. Pb and Fe were the elements that most contribute to the risk values in the sample points of the study area. Although, there is no human health risk in this scenario, this investigation highlight priority elements to future investigations in coal mine areas. In the current region, Pb and F- as priority elements for future studies.

Physicochemical assessment of anionic dye adsorption on bone char using a multilayer statistical physics model.

The statistical physics modeling is a reliable approach to interpret and understand the adsorption mechanism of both organic and inorganic adsorbates. Herein, a theoretical study of the adsorption mechanism of anionic dyes, namely reactive blue 4 (RB4), acid blue 74 (AB74), and acid blue 25 (AB25), on bone char was performed with a multilayer statistical physics model. This model was applied to fit the equilibrium adsorption data of these dyes at 298-313 K and pH 4. Results indicated that the global number of formed dye layers on the bone char varied from 1.62 to 2.24 for RB4, AB74, and AB25 dyes depending on the solution temperature where the saturation adsorption capacities ranged from 0.08 to 0.12 mmol/g. Dye molecular aggregation was also identified for these dyes where dimers and trimers prevailed at different operating conditions especially for adsorbates RB4 and AB74. Adsorption mechanism of these dyes was multimolecular and endothermic with adsorption energies from 10.6 to 20.8 kJ/mol where van der Waals interactions and hydrogen bonding could be present. This investigation contributes to understand the physicochemical variables associated to dye adsorption using low-cost adsorbents as bone char.

Groundwater quality assessment using a new integrated-weight water quality index (IWQI) and driver analysis in the Jiaokou Irrigation District, China.

Groundwater is an important water resource in arid and semi-arid regions. The impact of human activities on groundwater is increasing. After 60 years running, the groundwater quality and its formation mechanism are imperative questions needed to be answered in Jiaokou Irrigation District, Guanzhong Basin, China. In this study, the quality of groundwater in Jiaokou Irrigation District was assessed by a new integrated-weight water quality index (IWQI), and the groundwater chemistry is studied through integrated statistical, geostatistical and hydrogeochemical approaches. The patterns for the average anion and cation concentrations were HCO3- > SO42- > Cl- > NO3- > CO32- > NO2-, and Na+ > Mg2+ > Ca2+ > K+ > NH4+, respectively. Statistics showed that the major water chemistry types were HCO3-Na, SO4·Cl-Na, and Cl·SO4-Na. A new integrated-weight water quality index (IWQI) was proposed based on the entropy-weighted method and CRITIC method and showed excellent performance for explaining and evaluating the groundwater quality. The IWQI results show 65.33% of groundwater, mainly distributed in the central and western parts of this study area, was unsuitable for drinking. Furthermore, SO42－, HCO3－, Cl－, NO3－, and Na+ had more important effects on groundwater quality. The weathering process affecting groundwater quality in the study area is carbonate dissolution, followed by silicate weathering and evaporite dissolution, whereas the major geochemical processes include the dissolution and precipitation of calcite, as well as the dissolution of dolomite and gypsum (anhydrite). Cation exchange also plays an important role in the hydrogeochemical evolution of groundwater with a long residence time. Anthropogenic activities affecting groundwater quality included long-term irrigation infiltration and excessive use of fertilizers. The findings and the results of the study can improve understanding of the processes driving groundwater chemistry in Jiaokou Irrigation District, and can be used for reference to other similar regions in the world.

Assessment of hydrogeochemical characteristics and quality of groundwater resources in relation to risk of gastric cancer: comparative analysis of high- and low-risk areas in Iran.

The chemical quality of groundwater supplies in two high-risk area (HRA) and low-risk area (LRA) for gastric cancer in Iran was assessed through hydrogeochemical analysis and water quality indices. For this aim, Piper and Schoeller diagrams and water quality index (WQI) were applied. In addition, exposure to nitrate via drinking water and its corresponding risk were also assessed using Monte Carlo simulation technique. Data on physicochemical properties of groundwater resources were obtained from Iran Water Resources Management Company. Sampling and analysis of tap water for nitrate concentration were conducted in two cities of Shiraz (as a representative of LRA) and Ardabil (as a representative of HRA). According to Piper diagrams, the dominant hydrogeochemical facies of groundwater supplies in HRA and LRA were Na-HCO3 (43.75%) and Ca-HCO3 (41.77%), respectively. The predominant cations in groundwater resources of HRA were found to be Na+ (68.06%) and Ca2+ (31.94%). For LRA, the typical cations were in decreasing trend: Ca2+ (39.64%) > Mg2+ (18.35%) > Na+ (17.26%). For two areas, HCO3-, SO42- and Cl- were, respectively, the most frequent anions. Two-sample Wilcoxon test showed that there were statistically significant difference between two areas in terms of anions and cations concentrations (p value < 0.05). The mean of total hardness (Ca2+ + Mg2+) concentration of water supplies in LRA (528.1 mg/L) was higher than HRA (263.1 mg/L), whereas the mean of Na+ concentration was found to be lower in LRA (90.6 mg/L) compared with HRA (108.1 mg/L). The sum of nitrate intake and its risk in LRA was higher than HRA. WQI results showed that drinking water quality in HRA and LRA ranged from excellent to poor and most water resources were of a good quality class. Further studies are suggested to investigate the role of drinking water in the etiology of gastric cancer in Iran.

Synthesis of Fe-impregnated biochar from food waste for Selenium(â ¥) removal from aqueous solution through adsorption: Process optimization and assessment.

Iron-impregnated food waste biochar (Fe-FWB) was synthesized for Se(Ⅵ) removal from aqueous solution. The effect and interactive effects of different parameters including pyrolysis time, temperature, and Fe concentration were explored using response surface methodology (RSM) to enhance conditions to achieve the highest Se(Ⅵ) removal using Fe-FWB. Pyrolysis time was not significant for Se(Ⅵ) adsorption capacity of Fe-FWB, but temperature and Fe concentration were found to be significant. The highest adsorption was achieved at 3.47 h and 495.0 °C with an Fe concentration of 0.44 M. Fe-FWB synthesized under optimum conditions were used to investigate the kinetic, equilibrium, and thermodynamic adsorption of Se(Ⅵ). Se(Ⅵ) adsorption reached equilibrium within 6 h, and both pseudo-second order and pseudo-first order models were suitable for describing kinetic Se(Ⅵ) adsorption. The Freundlich model was found to suitably fit the equilibrium adsorption data than the Langmuir model. The highest adsorption capacity of Fe-FWB for Se(Ⅵ) was 11.7 mg g-1. Se(Ⅵ) adsorption on Fe-FWB was endothermic and spontaneous. The enthalpy change for Se(Ⅵ) adsorption was 54.4 kJ mol-1, and the entropy change was negative at 15-35 °C. The increment of solution pH from 3 to 11 decreased the Se(Ⅵ) adsorption from 19.2 to 7.4 mg g-1. The impact of interfering anions on Se(Ⅵ) adsorption followed the lineup: HCO3- > HPO42- > SO42- > NO3-. When compared to some adsorbents, the adsorption capacity of Se(Ⅵ) onto Fe-FWB was comparable even at neutral pH and the Fe-FWB was granular. These results indicate that Fe-FWB has prospective application in the removal of Se(Ⅵ) from aqueous solutions.

Hay-based activated biochars obtained using two different heating methods as effective low-cost sorbents: Solid surface characteristics, adsorptive properties and aggregation in the mixed Cu(II)/PAM system.

The main aim of the study was to compare the sorption capacity of hay-based activated biochars, obtained using conventional and microwave furnance, relative to copper(II) ions and ionic polyacrylamides (PAM). Surface properties of the solids were characterized by, inter alia, N2 adsorption/desorption isotherm method, whereas their tendency to aggregation was established turbidimetrically. Adsorption capacity of biochars were performed in the simple and mixed Cu(II)/PAM systems, i.e. the examined suspensions contained one or two adsorbates at the same time. The results indicated that biochar prepared in microwave furnance was characterized by larger micropore area and, as a result, it had higher adsorption capacity relative to Cu(II) ions. At pH 6, when the initial Cu(II) concentration equaled 100 mg/L, the biochar obtained by microwave heating adsorbed 81.5% of Cu(II) ions, whereas the one obtained by conventional heating - 51.6%. Due to high molecular weight, the PAM macromolecules could not penetrate the biochar micropores and thus the polymer adsorbed amounts were similar for both materials. For initial polymer concentration equal to 100 mg/L, the solids adsorbed 65-66.2% of cationic PAM containing 25% of quaternary amine groups. In the mixed system of anionic polyacrylamide and Cu(II) ions, the formation of Cu(II)-PAM complexes occurred, which favored both heavy metal and polymer adsorption on the solid surface. On the other hand, cationic polyacrylamide and heavy metal ions made the contact with the solid difficult for each other. What is more, ionic polyacrylamide and copper(II) ions stimulated the biochar aggregation due to surface charge neutralization and flocculation.

Toxicity and inhibition assessment of ionic liquids by activated sludge.

Toxicity of 13 ionic liquids (ILs) corresponding to different families were studied by inhibition respiration assays (15 min) using activated sludge. Toxicity increased as increasing the number of carbons in the alkyl-chain of imidazolium-based ILs, with EC50 values from 4.19 to 0.17 for 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) and 1-octyl-3-methylimidazolium chloride ([Omim][Cl]), respectively. An increase in toxicity was observed for aromatic-based ILs (pyridinium- and imidazolium-based ILs) due to the hydrophobic character of the head groups in comparison with linear structures as phosphonium and ammonium cations. Among to the anions studied fixing [Emim]+ as cation, [HSO4]- and [NTf2]- presented low EC50 values (0.34 mM and 1.69 mM, respectively) while [Cl]- and [EtSO4]- were considered harmless anions due to the hydrophilic character of chloride and the organic nature of [EtSO4]-. ILs toxicity/inhibition was determined by adding a biodegradable compound and measuring the sludge response after being in contact with the ILs for at least 15 h. The exposure of sewage sludge to ILs for more than 15 min used in short inhibition assays caused more toxic effect on microorganisms, even for [Choline][NTf2], previously defined as practically harmless (EC50 = 2.79 mM). Biodegradability assays confirmed the biodegradable nature of choline cation, related with TOC conversion of 40%, only due to cation consumption. No oxygen consumption or even lysis of microbial cells was observed for Tetrabutylammonium bis(trifluoromethylsulfonyl)imide and for 1-Ethyl-3-methylimidazolium hydrogensulphate due to the presence of anions previously defined as hazardous ([NTf2]- and [HSO4]-), maintaining their recalcitrant character to sewage systems.