Fractions Of Substances Research Articles

Combining Magnetic Ion Exchange Media and Microsand before Coagulation as Pretreatment for Submerged Ultrafiltration: Biopolymers and Small Molecular Weight Organic Matter

In order to reduce the fouling of ultrafiltration (UF) systems caused by influent organic matter and microbial activities in the membrane tank, a novel pretreatment process has been evaluated involving the combination of magnetic ion exchange media (MIEX), microsand, and alum coagulation. Using a continuous flow bench-scale UF membrane apparatus and synthetic water, the influence of MIEX and microsand with alum pretreatment on membrane fouling was studied in comparison to a conventional pretreatment by alum alone. It was found that the continuous addition of low doses of MIEX and microsand substantially reduced (∼50%) membrane fouling for nearly 60 days of operation, both in terms of reversible and irreversible fouling. MIEX adsorption increased the removal of dissolved organic matter, particularly hydrophobic and proteinaceous substances, and some fractions of humic-type substances, while the addition of microsand increased the density of flocs, and thus improved the removal of flocs and microorganisms (...

Tungsten accumulation by wild plants growing on mining wastes and contaminated soils

The transfer of metal and metalloid trace elements (MTEs) from contaminated soil to grapevines is a major issue for grape consumption and for the associated health risks. Based on an isotopic approach, we shed light on the concept of MTE bioavailability. The bioavailable fractions are identified by using the Sr-isotope ratio as a proxy for MTEs. This allows us to differentiate three soil reservoirs: the ‘current available fraction’ in soil water, the ‘reserve available fraction’ stored in mineral phases of the soil fractions, and the ‘non-available fraction’. The reserve available fraction, representing 10 to 60% of bulk soil depending on the MTE, includes the exchangeable, carbonates, humic substance and oxides fractions. The 87Sr/86Sr isotopic signatures of grape berries and vine leaves show an additional source of MTEs, which is imported by foliar uptake and can contribute up to 10% of the MTEs in leaves. In addition, root-uptake and translocation rates show high accumulation rates of Co, Sn and Cu, and low ones for As, Sb, Zn and Cd. A daily intake between 1 and 3 kg of (dry grapes) would reach the benchmark dose level for a 0.5% (BMDL0.5). While such a daily intake of grapes is unreasonable, consumption of other local vegetables and fruit would contribute to the daily intake. Hence, a chronic arsenic exposure is of great concern for human health in mining areas. We outline the importance of geochemical tracers, such as Sr isotopes, when determining the transfer and translocation of MTEs in plants. Our method presents a high-precision evaluation of the bioavailability and bioaccumulation of MTEs, and a better understanding of these processes in plants, thus leading to a better assessment of the environmental risk on human health.

Unravelling the influences of sewer-dosed iron salts on activated sludge properties with implications on settleability, dewaterability and sludge rheology

Although the beneficial impacts of iron dosing to sewer on activated sludge unit's performance, especially in relation to phosphate removal, have been reported, the extent of impacts on different sludge properties affecting the operation and performance of the activated sludge unit are not fully understood. In this study, we investigated the influences of iron salt dosing to sewer on both settleability and dewaterability of downstream activated sludge unit. We also examined, based on the comparative assessment of different key activated sludge properties, possible underlying factors responsible for the changes in sludge settleability and dewaterability. For this, iron chloride was dosed to a sewer reactor of integrated laboratory sewer-bioreactor system. The activated sludge samples were obtained from two separate reactors, an experimental sequencing batch reactor (SBR-E) downstream of sewer reactor receiving iron dosing and a control SBR (SBR-C) downstream of a sewer reactor without any iron dosing. Iron-conditioned sludge showed improved settleability and dewaterability over the unconditioned activated sludge. Mean differences in settleability and dewaterability between two sludges were 22.5 ± 7.8 mL/g (p < 0.05) and 7.8 ± 1.2% (p < 0.05), respectively. Iron-conditioned sludge showed lower contents of soluble extracellular polymeric substances (EPS) fractions, protein and polysaccharide contents, and monovalent-to-divalent (M+/D++) cations ratio, but higher humification index as compared to the unconditioned sludge. Iron-conditioned sludge exhibited marginal increment in mean particle size (Dv50) and settleable particle size classes (100–400 μm) but reduction in supracolloidal particle size classes (1–100 μm). In terms of sludge rheology, iron-conditioned sludge exhibited relatively lower relative sludge network strength, viscosity, yield stress, elastic/viscous/complex moduli (G′/G′′/G*), and damping factor tan(δ) but increased shear compliance (J) and shear strain (%) with time.The iron-conditioned sludge therefore exhibited relatively weaker deformation resistance and sludge elasticity. Based on the foregoing results, we posit the combined synergistic effect of favourable changes to the key sludge properties, might be responsible for the observed improvement in settleability and dewaterability of iron-conditioned sludge.

Effects of Shugan Hewei Decoction and active substance fractions on behavior and neurotransmitter levels in hypothalamus of depression model rats

To investigate the effects of Shugan Hewei Decoction and its active substance fractions on behavior and neurotransmitter levels in hypothalamus of depression model rats,and preliminarily explore its possible mechanism. Male SD rats were randomly divided into blank control group,model group,fluoxetine( positive control) group,Shugan Hewei Decoction high and low dose groups,high and low dose groups of three different substance fractions. After 3 weeks' CUMS and social isolation to induce models,intragastrical administration lasted for 7 d. Behavioral experiments( sucrose consumption test,open-field test,and forced swimming test) were then performed to evaluate the depression status of rats. Several neurotransmitters in hypothalamus of rats were determined by LC-MS/MS method,including dapamine( DA),norepinephrine( NE),serotonin( 5-HT),5-indoleacetic acid( 5-HIAA),γ-aminobutyric acid( GABA),and glutamic acid( Glu). As compared with the blank control group,the sucrose consumption was reduced( P<0. 01); the total distance and the number of crossing the central area were also significantly reduced( P< 0. 01,P< 0. 01),while the resting time increased significantly( P<0. 01); the forced swimming time was significantly prolonged( P<0. 01); DA,5-HT,NE,5-HIAA and GABA levels in hypothalamus were significantly reduced( P < 0. 01),while Glue level was significantly increased( P < 0. 01) in model group. As compared with the model group,all the above indexes had changes in fluoxetine group,Shugan Hewei Decoction whole recipe groups,volatile oils group,polysaccharides group,and terpenoids group( P<0. 01 or P<0. 05). Shugan Hewei Decoction whole recipe and its active substance fractions can improve the behavior of depression model rats and may exert anti-depression effects by regulating the content of neurotransmitters in the hypothalamus.

Adsorption of Cu(II) on soil humin: batch and spectroscopy studies

Understanding the interactions of humic substances with metal ions is of great importance in forecasting the behaviors and fates of trace metals in the environment. Humin is the least understood humic substance fraction due to its close association with the mineral matrix in soil. In this study, humin was prepared from three zonal soils (i.e., dark brown soil, yellow brown soil, and latosol) in eastern China by demineralization using HF–HCl solution after removing alkaline-soluble humic substance fractions. The adsorption properties of Cu(II) onto both humin and humic acid were examined using batch and spectroscopy (SEM, EDS, FTIR, XPS, and XAS) techniques. With respect to humic acid, humin was more aliphatic and less polar. The adsorption kinetics of humin and humic acid were best fit with pseudo-second-order kinetics equation, and the adsorption isotherms were well depicted by the Langmuir model. However, the quantity of adsorbed Cu(II) on humin was inferior to that of Cu(II) adsorbed onto humic acid. After adsorption, the surface morphology of humin and humic acid changed. Carboxyl, hydroxyl, aromatic N, and primary amine N on the surfaces of the two humic substance fractions took part in Cu(II) adsorption, and Cu(II) was bound with O/N and C atoms via inner-sphere complexation. Our results suggested that humin and humic acid had different adsorption capacity but similar adsorption mechanisms toward Cu(II).

Development of flow technology for the purification and production of food sunflower phospholipids

The completed research work is aimed at creating a continuous technology and machine-hardware purification scheme for phosphatide concentrate in an effective magneto-acoustic way. To separate modified of waste of deodorization and to obtain lecithins with a high content of phosphatidylcholines using distillation, selective solvent, ethyl alcohol and adsorbent-silica gel was used, and ultrasonic with an intensity of 10 W/cm2 in combination with a pulsating magnetic field of 2 Tl was used to increase its dissolving and absorbing ability. Such treatment in the stream provides obtaining a substantially bleached high-quality lecithin-containing product in the form of microgranules of an alcohol-insoluble fraction (remain on the filter) and a liquid fat-containing part with a low amount of waste absorbed by silica gel. The objectives of the study include studying the effect of hydrodynamic complex effects on the association and deassociation of free fatty acids and other related lipids in the composition of the waste of deodorization of sunflower oil, the rationale for the use of silica gel as an effective neutralizing and adsorbing agent, determining rational modes of the solvent (ethyl alcohol) distillation process in a vacuum molecular distiller for high-quality lecithin-containing liquid product. The relevance of the work «Improvement of the process and equipment for the distillation of waste of deodorization of vegetable oils processed in ultrasonic» is that at present in Russia this topic of the integrated use of ultrasonic, pulsating magnetic field and silica gel cleaning makes a significant novelty in Russian scientific works in this direction. The proposed technology for producing modified sunflower lecithins allows to obtain both fractionated lecithins with a mass fraction of acetone-insoluble substances of more than 60%, and skimmed, more hygrophilic lecithins with a mass fraction of acetone-insoluble substances up to 95% with an improved quality of cleaning from color and smelling substances at low acidity.

The research of rheological properties of bagasse based paste

In the horticultural industry, upon main products obtaining, the formation of the following secondary raw materials and production wastes: pulping,bagasse, tomato seeds, fruit seeds, vegetable peelings, etc. is concomitant. At the same time, the amount of secondary raw materials formed during fruit and vegetable raw materials processing varies from 5 to 85% of the initial raw materials mass going for processing, of which an average of 30% is sent to food products for food processing. The aim of the work was to study the possibility of bagasse using of direct extraction beet juice production in vegetable paste technology. To facilitate the process of bagasse pulping, pretreated with microwave heating, starch syrup, allowing to reduce the vegetable mass viscosity was proposed to use. As a result of research, it was found that the introduction of starch syrup in the bagasse in the amount of 10, 20 and 30%, along with an increase in the heating temperature, varying from 25 to 60, reduces the effective viscosity obtained after bagasse paste pulping. With an increase in the starch syrup dosage, an increase in the mass fraction of dry substances in beet paste and its liquefaction degree was observed as well. So, at a dosage of 10%, the liquefaction degree was 24.7%, at 20% - 45.1%, at 30% - 60.7%. Thus, the use of starch syrup in the production of beet paste from the bagasse of direct-pressed juice production makes it possible to adjust the vegetable mass viscosity purposefully, creating better conditions for subsequent technological operations. .

Gold Leaching with Humic Substances

The study results of gold leaching using the products of humic acids, as well as stage-by-stage fractionation of parent and gold-containing substances of these acids are presented. The gold content in the pregnant solution was up to 14–30 mg/l. Chemical analysis of the supernatant obtained by a stepwise change in pH of the solution and subsequent centrifugation determined that gold-bearing acids contain both organic and dissolved gold, which is stable to precipitation at pH 2. Fractionation of the original humic acids and subsequent leaching of gold by its individual fractions slows down the dissolution kinetics, and the fractions distinguished at different pH vary significantly in their activity. The most active is the fraction obtained by centrifugation at pH value of 4.6. The spectrum is presented, and the kinetics of gold dissolution by these acids modified by the cyanide complex is shown.

Evaluating the effects of the preoxidation of H2O2, NaClO, and KMnO4 and reflocculation on the dewaterability of sewage sludge

The preoxidation effects of H2O2, NaClO, and KMnO4 on the dewaterability of sewage sludge were compared by analyzing the changes in specific resistance to filtration (SRF), filter cake moisture content (FCMC), extracellular polymeric substance (EPS) fractions and components, and floc properties. The three oxidants varied in oxidation efficiency and exhibited distinctive mechanisms. NaClO not only destroyed sludge flocs and EPSs but also effectively caused cell lysis, resulting in release of a considerable amount of organic matters and subsequently significant deterioration of dewatering performance. The oxidation of H2O2 and KMnO4 was relatively mild and occurred mainly on the outer layers of the sludge flocs and cell-bound EPSs. By contrast, the SRF and FCMC of the sludge conditioned with a low dose of KMnO4 were slightly improved, and a fraction of soluble EPS was compressed because of the coagulation effect of the oxidation product MnO2. The pH of the sludge conditioned with H2O2 and KMnO4 showed no considerable change. Meanwhile, NaClO evidently increased the alkalinity of the sludge because of the hydrolysis effect. After the pH of the NaClO-treated sludge was readjusted to 7.0, the partial protonation efficiency slightly alleviated the deterioration of sludge dewatering performance. The preoxidized sludge was then subjected to reflocculation treatment using FeCl3, polyacrylamide, and a cationic starch-based flocculant, respectively. The combined treatment of preoxidation and reflocculation showed a high dewatering efficiency owing to their synergistic effect.

Evolution of Dissolved Organic Matter Along a Septic System Plume: Evidence of Sustained Biogeochemical Activity in the Groundwater Zone

AbstractDissolved organic matter (DOM) is an important energy source for biogeochemical reactions. However, DOM is often assumed to be recalcitrant in the groundwater zone due to extensive microbial processing in the overlying soil zone and long groundwater residence times. Consequently, further heterotrophic microbial processes proceed at inherently low rates. Septic systems provide an ideal opportunity to study the evolution of groundwater DOM due to the development of confined and easily identifiable plumes of known age. Here we use measures of DOM composition (size‐exclusion liquid chromatography, ultraviolet absorbance, and C:N) to quantify DOM evolution along an exceptionally well‐characterized septic‐impacted groundwater plume. Elevated concentrations (5 to 8 mg C/L) close to the tile bed decrease to values below 2 mg C/L with lower UV‐absorbing components normalized to overall DOM concentration (specific ultraviolet absorbance) along the six‐year‐old plume flow path. The humic substance fraction (HSF) comprises the largest percentage of DOM and decreases in concentration along the septic plume. HSF properties also change with travel time becoming lower in molecular weight, specific ultraviolet absorbance, and C:N. Denitrification continues along the length of the plume concomitant with changes in DOM and HSF composition. Thus, HSF, typically considered recalcitrant in subsurface environments, is actively cycled by microorganisms on multiyear time frames in accordance with the recent paradigm shift for soil organic matter evolution. Lastly, measures of DOM composition indicate changes in DOM that are not evident from measures of concentration alone.

Role of Polysaccharides in Diatom Thalassiosira pseudonana and its Associated Bacteria in Hydrocarbon Presence.

Diatoms secrete a significant amount of polysaccharides, which can serve as a critical organic carbon source for bacteria. The 2010 Deepwater Horizon oil spill exposed the Gulf of Mexico to substantial amounts of oil that also impacted the phytoplankton community. Increased production of exopolymeric substances was observed after this oil spill. Polysaccharides make up a major fraction of exopolymeric substances; however, their physiological role during an oil spill remains poorly understood. Here, we analyzed the role of polysaccharides in the growth and physiology of the oil-sensitive diatom Thalassiosira pseudonana and how they shape the surrounding bacterial community and its activity in the presence of oil. We found that inhibition of chrysolaminarin synthesis had a negative effect on the growth of T pseudonana and intracellular monosaccharide accumulation, which in turn suppressed photosynthesis by feedback inhibition. In addition, by acting as a carbon reserve, chrysolaminarin helped in the recovery of T pseudonana in the presence of oil. Inhibition of chrysolaminarin synthesis also influenced the bacterial community in the free-living fraction but not in the phycosphere. Exposure to oil alone led to increased abundance of oil-degrading bacterial genera and the activity of exoenzyme lipase. Our data show that chrysolaminarin synthesis plays an important role in the growth and survival of T pseudonana in the presence of oil, and its inhibition can influence the composition and activity of the surrounding bacterial community.

Low-Frequency Magnetic Scanning Device and Algorithm for Determining the Magnetic and Non-Magnetic Fractions of Moving Metallurgical Raw Materials

The development of an algorithm to automate the process of measuring the magnetic properties of macroscopic objects in motion is an important problem in various industries, especially in ferrous metallurgy and at factories where ferrous scrap is a strategic raw material. The parameter that requires work control is the hidden mass fraction of a non-magnetic substance that is present in the ferromagnetic raw material. The solution to this problem has no prototypes. In our work, a simple measuring device and a mathematical algorithm for calculating the mass fraction of the non-magnetic fraction in a strongly magnetic matrix were developed. The device is an inductance coil, in which the angle of the electromagnet losses is related to the mass of the magnetic material moving the coil. The magnitude of the instantaneous values of the lost angle integral was compared with the result of weighing the object on scales. This allowed us to calculate the proportion of the magnetic and non-magnetic fractions. The use of this prototype is herein illustrated. The experimental results of the determination of the magnetic-fractional composition depending on the mass of scrap metal and its bulk and the magnetic characteristics are presented.

Investigation of lipophilic substances of the leaves and flowers of spindle tree (Euonymus Europaea L.)

Spindle Tree (Euonymus europaea L.) has long been used in folk medicine for the treatment of dermatomycoces and as an antiparasitic and anthelmintic agent. However, with what substances it is associate this activity, it is not known for certain. In a previous work, a was developed extracting scheme from the bark of Spindle Tree (Euonymus europaea L.) to obtain water-soluble and lipophilic substances and the composition of the lipophilic fraction was studied using the GC-MS method.&#x0D; The purpose of this work was to obtain lipophilic substances from the flowers and leaves of Spindle Tree and to compare their chemical composition with the composition of substances obtained from the bark of the plant.&#x0D; Flowers and leaves were dried in a drying oven at a temperature of 52 °C, after which a fraction of lipophilic substances was obtained by extraction with petroleum ether. This fraction was analyzed using gas chromatography-mass spectrometry (GC-MS). For this, a chromatographic column was used, which was washed with methanol (model NR-5ms, length 30 m, diameter 0.25 mm, filler: 95% dimethylpolysiloxane + 5% diphenylpolysiloxane; carrier gas ‒ helium with a constant flow of 1.5 ml/min) and 6C / MS Agilent Technologies 6890 N / 5975 B mass spectrometer (USA).&#x0D; The etxtraction by petroleum ether was obtained fraction of lipophilic substances in the amount of 0.83% of the taken weight of dried flowers and 0.62% by weight of dried leaves. In total, 28 compounds were detected in flowers, and 19 in leaves. It was established that flowers and leaves of Spindle Tree, like bark, are characterized by a high content of paraffinic carbohydrates (from C20H42 to C31H64). Their content is higher in flowers (more than 50% of the composition of the fraction), and in leaves and bark ≈ 35%. Steroid and terpene compounds in the lipophilic fractions of the leaves and bark of the plant are respectively 28.26% and 24.32%. Among them quantitatively dominated by freedeen. A rather high content of squalene (2.06%) was found in the leaves of the plant. Among other compounds, a significant proportion of fatty acids and their esters, of which 24.59% by weight of the lipophilic fraction of flowers and 14.74% by weight of the lipophilic fraction of leaves.&#x0D; An analysis of the results indicates a greater promise for the use in medicine of lipophilic substances of the bark and leaves of Spindle Tree than of flowers.

RESEARCH OF THE CHANGE OF THE PRODUCT CONSISTENCE DURING HIS ULTRASOUND PROCESS

This article presents the results of studying the effect of ultrasound on the consistency of products. The task of the study was to identify the possibility of using ultrasound to change the consistency of the product from puree to homogenized. For this purpose, laboratory samples of apple puree were periodically processed on an ultrasonic generator at a frequency of 21.7 kHz, for different duration of exposure to ultrasound from 1 minute to 20 minutes. After processing, measurements of physicochemical parameters were carried out the mass fraction of soluble solids, temperature and viscosity. When analyzing the obtained results, it was found that, depending on the exposure time, the indicators of the mass fraction of dry substances in samples No.1, No.2, No.3 slightly increased relative to the control sample from a value of 11.9 to 12.4 V of sample No.4, in which the duration of exposure to ultrasound was 20 minutes, the indicator of the mass fraction of dry substances increased more significantly up to 13.8%. The same dynamics is observed in the obtained values of the viscosity of the product, which gradually increases in proportion to the exposure time from sample No.1 to sample No.4 (4600-6500 Centipoise (CP)). In addition, a comparative assessment of the organoleptic characteristics of experimental samples (taste, color, aroma and texture) was carried out after their ultrasonic treatment, depending on the duration of exposure. It was found that all the organoleptic characteristics of apple puree with an increase in the duration of ultrasonic treatment with a given parameter at a frequency of 21.7 kHz, changed depending on the time of exposure. Thus, the consistency changed from a “granular” structure (in the control sample) to a homogeneous homogenized (in sample No.3). In sample No.4 (with an exposure time of 20 minutes), mashed potatoes were obtained with a fine, finely divided creamy mass. Consequently, the effect of ultrasound with a given frequency of 21.7 kHz for at least 10 minutes allows a pureed product with a puree-like structure to obtain a homogenized puree.

РАЗРАБОТКА КОМПОНЕНТНОГО СОСТАВА ЭКОЛОГИЧЕСКИ ЧИСТОЙ ВОДНО-ДИСПЕРСИОННОЙ КРАСКИ НА ОСНОВЕ ПОЛИВИНИЛАЦЕТАТНОЙ ДИСПЕРСИИ

Interior paint is important for interior decorating; this is followed by a long time working with the col-oring material and a constant stay in rooms with the paint. Unfortunately, not all paints provide com-fortable and safe use. This article presents the development of eco-friendly water-dispersion paint based on polyvinyl acetate dispersion. This paint provides protection from carcinogenic, mutagenic and toxic effects. The main environmental requirements set by the standards are considered; the con-tent of substances in the paint that harms people is monitored. The influence of some paint compo-nents on person’s functionality and the possibility of their replacing without quality reduction is dis-closed in the paper. The main physical and mechanical properties such as conditional viscosity, densi-ty, mass fraction of nonvolatile substances, coating adhesion, milling degree, resistance to static ac-tion of water and weather resistance are determined. Attention is paid to the applied research meth-ods. As a result of testing, a water-dispersion paint with high technical characteristics is obtained. It can be used in all types of buildings and structures and be recommended for children's, medical and preventive institutions.

Effect of Polyoxymethylene Dimethyl Ethers/Diesel Blends on Fuel Properties and Particulate Matter Oxidation Activity of A Light-Duty Diesel Engine

Polyoxymethylene dimethyl ethers (PODE) was blended in diesel at volume ratios of 0 %, 10 %, 20 %, and 30 % (denoted as P0, P10, P20, and P30). The experimental study was carried on an unmodified YD480Q diesel engine. An engine exhaust particle sizer was introduced to analyze the particulate matter (PM) concentration and particle size distribution of diesel engine emission. The evaporation-oxidation characteristics of the PODE/diesel blends and the effect of the fuel blends on the oxidative activity of PM were investigated by thermogravimetric analysis and Arrhenius theorem. The results showed that blending PODE in diesel improved the evaporation-oxidation characteristics of the fuel and decreased the apparent activation energy of the fuel blends. PODE played a positive role in reducing PM emissions. The particle total number concentration of P30 decreased 28.29 ~ 66.60 % and the particle total volume density decreased 54.16 ~ 80.06 % compared to diesel. The particle size distribution shifted to a smaller particle size as the PODE blending ratio was increased. The mass fraction of the volatile substances (VS) increased and the mass fraction of the dry soot (DS) decreased by employing PODE as a diesel additive. Also, the oxidation activity of VS increased as the PODE blending ratio was increased. The oxidation activity of DS climbed to the peak when the PODE blending ratio was 20 % and then decreased.

Binding characteristics of heavy metals to humic acid before and after fractionation by ferrihydrite

The fractionation of humic substances (HS) at the mineral and water interface can change the constituents and reactivity of HS, but there is still a lack of the understanding of the effects of HS fractionation on the binding characteristics of heavy metals to HS. In this study, the binding characteristics of five heavy metals (Cd, Cu, Ni, Pb, and Zn) to humic acid (HA) before and after adsorption by ferrihydrite were investigated by employing two-dimensional correlation spectroscopy (2D COS) integrated with synchronous fluorescence and Fourier transform infrared (FTIR) spectroscopies. 2D COS analyses of the fluorescence results indicated that the susceptibility of the fluorescence of humic-like fraction to heavy metals significantly decreased after the adsorption of HA by ferrihydrite, which may be due to the fact that humic-like components were preferentially adsorbed by ferrihydrite. However, the fractionation processes did not alter the metal binding sequence and affinity to different HA components. 2D COS analyses of the FTIR results suggested that fractionation processes decreased the susceptibility of COO− groups to heavy metals, and changed the metal binding sequence to polysaccharides C-O and aryl groups, with the exception of Pb. Furthermore, model calculations showed that the binding ability of heavy metals to both humic-like and fulvic-like fractions decreased after the adsorption of HA by ferrihydrite. The results of this study contribute to predicting heavy metal behavior in the environment.

Accelerating effects of humin on sulfide-mediated azo dye reduction

As an important fraction of humic substances, humin has been found capable of stimulating bioreduction reactions. However, whether humin could promote abiotic reduction and the effects of coexisting soluble humic substance and insoluble mineral remained unsolved. In this study, a humin sample was isolated from a paddy soil. Cyclic voltammetry, electron paramagnetic resonance, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses of the humin indicated the existence of redox-active quinone moieties and other oxygen-containing groups. The humin could be reduced by sulfide and its presence stimulated the abiotic reduction of acid red 27 (AR27) and four other azo dyes by sulfide. In the presence of 100–1000 mg/L intact humin, the sulfide-mediated AR27 reduction efficiency in 7 d was enhanced from 56.3% to 92.5%. The stimulating behavior of intact humin was observed for 100–300 mg/L AR27 and increased with the increase of sulfide concentration (1.2–3.0 mM). Much higher stimulating effects were found with the presence of humin pre-reduced by sulfide. Moreover, for sulfide-mediated AR27 reduction, the coexistence of humin (500 mg/L) and humic acid (10–30 mg/L) or Wyoming sodium-montmorillonite (SWy-2, 1–4 g/L) led to better promotion activities than the presence of single component. And synergistic promotion of sulfide-mediated AR27 reduction was observed with coexisting humin and SWy-2 due to enhanced Fe(II) production. These findings extended our understanding of the influence of humin on reductive transformation of pollutants in the environment.

Developing a groundwater watch list for substances of emerging concern: a European perspective

There is growing concern globally about the occurrence of anthropogenic organic contaminants in the environment, including pharmaceuticals and personal care products. This concern extends to groundwater, which is a critical water resource in Europe, and its protection is a priority to the European Commission, the European Union (EU) Member States and national agencies across Europe. Maintaining good groundwater status supports improved public health, economic growth and sustains groundwater dependant ecosystems. A range of measures have been introduced for regulating several substances that have impacted groundwater (e.g. nitrate and pesticides). However, these measures only cover a small fraction of anthropogenic substances that could pollute groundwater. Monitoring for these unregulated substances is currently very limited or not carried out at all. Therefore, a coordinated European-wide approach is needed to identify, monitor and characterise priority substances or groups of substances that have the potential to pollute groundwater. This evidence base is critical for policy development and controls on these currently unregulated substances. The European Commission highlighted this as a need during the review of the EU Groundwater Directive Annexes in 2014, when the requirement to develop a Groundwater Watch List (GWWL) was established. This paper describes the approach that has been developed through a voluntary initiative as part of the EU CIS Working Group Groundwater to establish the voluntary EU GWWL. The process for developing the GWWL is one that has brought together researchers, regulators and industry, and is described here for the first time. A summary of the key principles behind the methodology is presented as well as results from pilot studies using per- and polyfluoroalkyl substances and pharmaceuticals. These explore and support the viability of the GWWL process, an important step towards its adoption and its future use for groundwater protection across Europe.

Diversity in the Mechanisms of Humin Formation during Composting with Different Materials.

Humins (HMs) play a very important role in various environmental processes and are crucial for regulating global carbon and nitrogen cycles in various ecosystems. Composting is a controlled decomposition process accompanied by the stabilization of organic solid waste materials. During composting, active fractions of organic substances can be transformed into HMs containing stable and complex macromolecules. However, the structural heterogeneity and formation mechanisms of HMs during composting with various substrates have not been clarified. Here, the structure and composition of HMs extracted from livestock manure (LM) and straw (SW) during composting were investigated by excitation-emission matrices spectroscopy and Fourier transform infrared spectroscopy. The results showed that the stability and humification of LM-HM were lower than that of SW-HM. The parallel factor analysis components of the HM in LM composting contained the same fluorescent unit, and the intermediate of cellulose degradation affected the structure of the HM from SW composting. Structural equation modeling demonstrated that low-molecular-weight compounds were key factors in humification. On the basis of the structure and key factors impacting HM, we constructed two mechanisms for the formation of HM from different composting processes. The LM-HMs from different humification processes have multiple identical fluorescent structural units, and the high humification of SW is affected by its polysaccharide constituents, which contains a fluorescent component in their skeleton, providing a basis for studying HM in composting.