Initial Total Concentration Research Articles

Storage Effects on the Physicochemical Properties, Phytochemical Composition, and Sugars in Red-Fleshed Cultivars, ‘Rubycot’ Plumcot, and ‘Queen Garnet’ Plum

Domestic storage conditions can have a significant impact on the composition of phytochemicals and sugars in stone fruits. This study aimed to evaluate the effect of two domestic storage temperatures (4 and 23 °C) on the physicochemical properties, phytochemical composition, and sugars of ‘Rubycot’ (RC) plumcot, a novel stone fruit variety, and ‘Queen Garnet’ (QG) plum. Initially, RC had a lower total anthocyanin concentration (TAC) than QG, but TAC in RC increased significantly (p < 0.05) during storage, peaking at +95% after 7 days at 23 °C, while QG reached +60% after 14 days. At 4 °C, TAC increased for both varieties (RC +30%, QG +27%). RC had a higher initial total phenolic content (TPC), which also increased for both fruits. QG had a significantly higher initial total quercetin concentration (TQC), increasing by 40% (p < 0.05) at 23 °C. The initial total carotenoid concentration in QG was higher than that in RC, but after 10 days at 23 °C, RC had a higher carotenoid concentration than QG. Both varieties showed similar sugar profiles, with QG starting higher but decreasing over time at both storage temperatures. Results from this study showed that ambient storage significantly increases total anthocyanins, total quercetins, and TPC in RC and QG. However, it is important to evaluate the textural and sensory properties of stored RC and QG in terms of consumer acceptability of the stored fruits.

Electron beam irradiation developed cinnamon oil- (polyvinyl alcohol/gum tragacanth)/graphene oxide dressing hydrogels: Antimicrobial and healing assessments

This study aimed to develop hydrogel dressings for wound healing composed of gum tragacanth (TG) and polyvinyl alcohol (PVA) loaded with Graphene oxide (GO) and Cinnamon oil (CMO) using electron beam irradiation. The impact of the preparation conditions and the incorporation of GO and CMO on the characteristic properties of the prepared CMO-(PVA/TG)-GO wound dressings was evaluated. The healing-related characteristics were assessed, including fluid absorption and retention, water vapor transmission rate (WVTR), hemolytic assay, and antimicrobial potential. Wound healing efficacy was evaluated using a scratch wound healing assay. FTIR analysis verified the chemical structure, whereas scanning electron microscopy demonstrated an appropriate porosity structure necessary for optimal wound healing. The gel content increases with the initial total polymer concentration and the irradiation dose increases. Higher GO and CMO content improve the gel content and decreases swelling. WVTR decreases with the rise in CMO content. In vitro, cytotoxicity and hemolytic potency assessments confirmed their biocompatibility. The incorporation of GO and CMO enhances the antimicrobial activity and wound-healing capability. Based on the above findings, CMO-(PVA/TG)-GO dressings show promising potential as candidates for wound care.

High-efficiently utilizing micro-nano ozone bubbles to enhance electro-peroxone process for rapid removal of trace pharmaceutical contaminants from hospital wastewater

The electro-peroxone (EP) process encounters two inherent challenges in wastewater treatment: sluggish O2/O3 transfer and substantial ozone waste. To overcome these limitations, we introduced micro-nano bubbles (MNBs) aeration to enhance O2/O3 dissolution and diffusion, ultimately aiming to improve the removal of trace pharmaceutical contaminants from hospital wastewater. In the MNBs aeration system, the ozone transfer coefficient ranging from 0.536 to 0.265 min−1, significantly surpassing that of conventional aeration (0.220 to 0.090 min−1) by approximately 2 to 4.5 times. Consequently, the EP process under MNBs aeration significantly enhanced ozone-resistant ibuprofen (IBU) removal, achieving a removal rate of 98.4 ± 1.5 %, far exceeding the 47.3 ± 4.7 % observed with conventional aeration. This significant improvement was attributed to the heightened production of hydroxyl radicals (•OH), reaching 0.97 × 10−9 M s, compared to only 0.28 × 10−9 M s in conventional aeration. The mechanism behind the enhanced •OH production in the MNBs-EP process relied primarily on two factors: improved O2/O3 dissolution due to high internal pressure/large surface and enhanced O3/H2O2 activation from high collapse energy. These factors together contributed to the robust oxidation capability of the MNBs-EP system. As a result, over 97 % removal efficiency was achieved for five representative pharmaceutical pollutants (sulfamethoxazole, ribavirin, norfloxacin, tetracycline and ampicillin) in just 1 min. Furthermore, when applied to real hospital wastewater, the MNBs-O3-E treatment system reduced all 15 detected trace pharmaceutical compounds to below 10 ng L−1 and achieved 14 types of pollutants with removal rates of over 85 % within 15 min, resulting in an ultrahigh total removal rate of 98.6 %, from an initial total concentration of 2108 ng L−1 to less than 30 ng L−1. Thus, micro-nano aeration endowed the EP process as a promising advanced oxidation system for rapid and highly-effective removal of trace pharmaceutical contaminants from hospital wastewater.

Development of simplified probabilistic models for predicting phytoextraction timeframes of soil contaminants: demonstration at the DDX-contaminated Kolleberga tree nursery in Sweden

Phytoextraction, utilizing plants to remove soil contaminants, is a promising approach for environmental remediation but its application is often limited due to the long time requirements. This study aims to develop simplified and user-friendly probabilistic models to estimate the time required for phytoextraction of contaminants while considering uncertainties. More specifically we: i) developed probabilistic models for time estimation, ii) applied these models using site-specific data from a field experiment testing pumpkin (Cucurbita pepo ssp. pepo cv. Howden) for phytoextraction of DDT and its metabolites (ΣDDX), iii) compared timeframes derived from site-specific data with literature-derived estimates, and iv) investigated model sensitivity and uncertainties through various modelling scenarios. The models indicate that phytoextraction with pumpkin to reduce the initial total concentration of ΣDDX in the soil (10 mg/kg dw) to acceptable levels (1 mg/kg dw) at the test site is infeasible within a reasonable timeframe, with time estimates ranging from 48–123 years based on literature data or 3 570–9 120 years with site-specific data using the linear or first-order exponential model, respectively. Our results suggest that phytoextraction may only be feasible at lower initial ΣDDX concentrations (< 5 mg/kg dw) for soil polishing and that alternative phytomanagement strategies should be considered for this test site to manage the bioavailable fraction of DDX in the soil. The simplified modes presented can be useful tools in the communication with site owners and stakeholders about time approximations for planning phytoextraction interventions, thereby improving the decision basis for phytomanagement of contaminated sites.

Preparation and Performance Verification of a Solid Slow-Release Carbon Source Material for Deep Nitrogen Removal in Urban Tailwater.

Urban tailwater typically has a low carbon-to-nitrogen ratio and adding external carbon sources can effectively improve the denitrification performance of wastewater. However, it is difficult to determine the dosage of additional carbon sources, leading to insufficient or excessive addition. Therefore, it is necessary to prepare solid slow-release carbon source (SRC) materials to solve the difficulty in determining the dosage of carbon sources. This study selected two SRCs of slow-release carbon source 1 (SRC1) and slow-release carbon source 2 (SRC2), with good slow-release performance after static carbon release and batch experiments. The composition of SRC1 was: hydroxypropyl methylcellulose/disodium fumarate/polyhydroxy alkanoate (HPMC/DF/PHA) at a ratio of 3:2:4, with an Fe3O4 mass fraction of 3%. The composition of SRC2 was: HPMC/DF/PHA with a ratio of 1:1:1 and an Fe3O4 mass fraction of 3%. The fitted equations of carbon release curves of SRC1 and SRC2 were y = 61.91 + 7190.24e-0.37t and y = 47.92 + 8770.42e-0.43t, respectively. The surfaces of SRC1 and SRC2 had a loose and porous morphological structure, which could increase the specific surface area of materials and be more conducive to the adhesion and metabolism of microorganisms. The experimental nitrogen removal by denitrification with SRCs showed that when the initial total nitrogen concentration was 40.00 mg/L, the nitrate nitrogen (NO3--N) concentrations of the SRC1 and SRC2 groups on the 10th day were 2.57 and 2.66 mg/L, respectively. On the 20th day, the NO3--N concentrations of the SRC1 and SRC2 groups were 1.67 and 2.16 mg/L, respectively, corresponding to removal efficiencies of 95.83% and 94.60%, respectively. The experimental results indicated that SRCs had a good nitrogen removal effect. Developing these kinds of materials can provide a feasible way to overcome the difficulty in determining the dosage of carbon sources in the process of heterotrophic denitrification.

Blood Kinetics of Lipophilic and Proteinophilic Pollutants during Two Types of Long-Term Fast in King Penguins.

In vertebrates, fasting is an intricate physiological process associated with strong metabolic changes, yet its effect on pollutant residue variation is poorly understood. Here, we quantified long-term changes in plasma concentrations of 20 organochlorine and 16 perfluoroalkyl pollutants in king penguins Aptenodytes patagonicus during the breeding and molting fasts, which are marked by low and high levels of protein catabolism, respectively, and by strong lipid use. The profile of measured pollutants in plasma was dominated by perfluorooctanesulfonic acid (PFOS, initial relative contribution of 60%). Initial total pollutant concentrations were similar in molting (3.3-5.7 ng g-1 ww) and breeding penguins (range of 4.2-7.3 ng g-1 wet weight, ww). Long-term fasting (25 days) for molting and breeding led, respectively, to a 1.8- and 2.2-fold increase in total plasma pollutant concentrations, although the rate and direction of change were compound-specific. Hexachlorbenzene (HCB) and PFOS concentrations increased in plasma (net mobilization) during both types of fasting, likely due to lipid use. Plasma perfluoroundecanoate (PFUnDA) and perfluorotridecanoate (PFTrDA) concentrations increased in breeders (net mobilization) but decreased in molting individuals (net excretion), suggesting a significant incorporation of these pollutants into feathers. This study is a key contribution to our understanding of pollutant variation in blood during long-term fasting in wildlife.

Engineered algal systems for the treatment of anaerobic digestate: A meta-analysis

The objective of this review was to provide quantitative insights into algal growth and nutrient removal in anaerobic digestate. To synthesize the relevant literature, a meta-analysis was conducted using data from 58 articles to elucidate key factors that impact algal biomass productivity and nutrient removal from anaerobic digestate. On average, algal biomass productivity in anaerobic digestate was significantly lower than that in synthetic control media (p < 0.05) but large variation in productivity was observed. A mixed-effects multiple regression model across study revealed that biological or chemical pretreatment of digestate significantly increase productivity (p < 0.001). In contrast, the commonly used practice of digestate dilution was not a significant factor in the model. High initial total ammonia nitrogen suppressed algal growth (p = 0.036) whereas initial total phosphorus concentration, digestate sterilization, CO2 supplementation, and temperature were not statistically significant factors. Higher growth corresponded with significantly higher NH4–N and phosphorus removal with a linear relationship of 6.4 mg NH4–N and 0.73 mg P removed per 100 mg of algal biomass growth (p < 0.001). The literature suggests that suboptimal algal growth in anaerobic digestate could be due to factors such as turbidity, high free ammonia, and residual organic compounds. This analysis shows that non-dilution approaches, such as biological or chemical pretreatment, for alleviating algal inhibition are recommended for algal digestate treatment systems.

Biodegradation of a complex hydrocarbon mixture and biosurfactant production by Burkholderia thailandensis E264 and an adapted microbial consortium.

Bioremediation is considered to be an effective treatment for hydrocarbon removal from polluted soils. However, the effectiveness of this treatment is often limited by the low availability of targeted contaminants. Biosurfactants produced by some microorganisms can increase organic compound solubility and might then overcome this limitation. Two different inocula producers of biosurfactants (Burkholderia thailandensis E264 and SHEMS1 microbial consortium isolated from a hydrocarbon-contaminated soil) were incubated in Bushnell-Haas medium supplemented with hydrocarbons to investigate their biodegradation potential. Experimental results showed their ability to degrade 9.1 and 6.1% of hydrocarbons respectively after 65 days of incubation with an initial total hydrocarbon concentration of 16 g L-1. The biodegradation was more effective for the light and medium fractions (C10 to C36). B. thailandensis and SHEMS1 consortium produced surfactants after 14 days of culture during the stationary phase with hydrocarbons as the sole carbon and energy source. However, biosurfactant production did not appear to directly increase hydrocarbon degradation efficiency. The complexity and recalcitrance of hydrocarbon mixture used in this study appeared to continue to limit its biodegradation even in the presence of biosurfactants. In conclusion, B. thailandensis and SHEMS1 consortium can degrade recalcitrant hydrocarbon compounds and are therefore good candidates for the bioremediation of environments polluted by total hydrocarbons.

Rapid dilution effectively decreases hydrocarbons following small oil spills, but impacts on microeukaryote communities are still observed

Dilution affects the distribution and weathering of oil following a spill into coastal seawater, but including dilution in experiments is rare. In open water, dilution is expected to rapidly reduce the concentrations of hydrocarbons, and estimates of impacts and microbial responses from batch experiments may overestimate what happens during a spill event. Three experiments carried out in the southern Gulf of St. Lawrence incorporated periods of incubation of natural microbial communities with either Heidrun medium crude or Bunker C fuel oil followed by dilutions using unexposed seawater. Higher concentrations of n-alkanes (C10 – C35) in Heidrun, resulted in higher initial total hydrocarbon concentrations in incubations with Heidrun compared to Bunker C. Similar polycyclic aromatic hydrocarbon concentrations and potential toxicity were measured in the water column for both oils. Dilution effectively decreased the hydrocarbon concentrations, reducing them to background levels after two dilutions (13.8-fold). Neither the abundance nor the diversity of the prokaryote community was strongly affected by the addition of oil. The natural coastal microbiome was dominated by bacteria that may be facultative hydrocarbon degraders. The abundance of phytoplankton and the diversity of the microeukaryote community decreased during the second incubation in response to both Heidrun and Bunker C, potentially due to photooxidative byproducts produced under full sunlight. Dilution appears to limit the bacterial response to oil, but low hydrocarbon concentrations may still be linked to impacts on the microeukaryote community.

Enhanced nitrogen removal by bioelectrochemical coupling anammox and characteristics of microbial communities

To investigate the bioelectrochemical enhanced anaerobic ammonia oxidation (anammox) nitrogen removal process, a bioelectrochemical system with coupled anammox cathode was constructed using a dual-chamber microbial electrolysis cell (MEC). Specifically, a dark incubation batch experiment was conducted at 30 ℃ with different influent total nitrogen concentrations under an applied voltage of 0.2 V, and the enhanced denitrification mechanism was investigated by combining various characterization methods such as cyclic voltammetry, electrochemical impedance spectroscopy and high-throughput sequencing methods. The results showed that the total nitrogen removal rates of 96.9%±0.3%, 97.3%±0.4% and 99.0%±0.3% were obtained when the initial total nitrogen concentration was 200, 300 and 400 mg/L, respectively. In addition, the cathode electrode biofilm showed good electrochemical activity. High-throughput sequencing results showed that the applied voltage enriched other denitrifying functional groups, including Denitratisoma, Limnobacter, and ammonia oxidizing bacteria SM1A02 and Anaerolineaceae, Nitrosomonas europaea and Nitrospira, besides the anammox bacteria. These electrochemically active microorganisms comprised of ammonium oxidizing exoelectrogens (AOE) and denitrifying electrotrophs (DNE). Together with anammox bacteria Candidatus Brocadia, they constituted the microbial community structure of denitrification system. Enhanced direct interspecies electron transfer between AOE and DNE was the fundamental reason for the further improvement of the total nitrogen removal rate of the system.

An indigenous tubular ceramic membrane integrated bioreactor system for biodegradation of phthalates mixture from contaminated wastewater.

Endocrine-disrupting phthalates (EDPs) are widely used as plasticizers for the manufacture of different plastics and polyvinyl chloride by providing flexibility and mechanical strength. On the other hand, they are categorized under priority pollutants list due to their threat to human health and the environment. This study examined biodegradation of a mixture of dimethyl, diethyl, dibutyl, benzyl butyl, di-2-ethylhexyl, and di-n-octyl phthalates using a CSTB (continuous stirred tank bioreactor) operated under batch, fed-batch, continuous, and continuous with biomass recycle operation modes. For operating the CSTB under biomass recycle mode, microfiltration using an indigenous tubular ceramic membrane was employed. Ecotoxicity assessment of the treated water was carried out to evaluate the toxicity removal efficiency by the integrated bioreactor system. From the batch experiments, the EDPs cumulative degradation values were 90 and 75% at 1250 and 1500mg/L total initial concentration of the mixture, respectively, whereas complete degradation was achieved at 750mg/L. In the fed-batch study, 93% degradation was achieved at 1500mg/L total initial concentration of the mixture. In continuous operation mode, 94 and 85% degradation efficiency values were achieved at 43.72 and 52.08mg/L⋅h inlet loading rate of phthalate mixture. However, continuous feeding with 100% biomass recycle revealed complete degradation at 41.67mg/L⋅h inlet loading rate within the 84h operation period. High seed germination index and low mortality percentage of brine shrimps observed with phthalate degraded water from the integrated bioreactor system revealed its excellent potential in the treatment and toxicity removal of phthalates contaminated environment.

Research on the distribution of S species in the pressure oxidation leaching process of SrS solution

Strontium compounds apply extensively in a variety of domains. Commonly, strontium compounds are made by carbonization of SrS solution. H2S is readily generated in this process. To avoid H2S byproducing, a novel strategy for the pressure oxidation leaching process of SrS solution was used. The overoxidation of sulfides was restrained, and a higher separation efficiency of Sr and S was obtained, which was beneficial for synthesizing other strontium compounds. The effects of the oxidation pH environment, reaction temperature, initial total sulfide concentration and reaction time on the conversion ratio of S species were investigated. The results showed that S0 was preferably generated in a near-neutral, low-temperature and low initial total sulfide concentration oxidation environment. The optimum oxidation conditions were summarized experimentally: 48 mL/L HCl (pH = 7.11), 25 °C reaction temperature, 8.2 g/L initial total sulfide concentration and 60 min reaction time. The optimum conversion ratios were obtained under optimum oxidation conditions as follows: χsulfide 2.3%, χH2S 0.5%, χS0 81.5%, χinter 10.0% and χS - Sr 5.7%. SrCl2 crystal was recovered finally from the leachate. At last, the pressure oxidation mechanism of SrS was discussed.

Nitrogen transformation during fermentation in agricultural biogas plants

The aim of the present study was to determine changes in the organic nitrogen fraction in the liquid fraction of the digestate during laboratory tests of mono- and co-digestion. Three agricultural wastes were tested: distillery residue, cattle slurry and corn silage. In the mono-fermentation tests, the initial total nitrogen concentration depended on the feedstock used. As a result of the hydrolysis and ammonification of the organic matter contained in the feedstocks, there was an increase in ammonium nitrogen concentration after 28 days of fermentation. Analysis of organic nitrogen fractions showed that different organic nitrogen fractions predominated in each of the feedstocks. Four co-digestion tests were performed with 20% and 80% inoculum content and the combination of feedstocks used in the mono-fermentation. Proper evaluation of the transformation of nitrogen forms for the tests with 20 and 80% inoculum participation required the calculation of concentrations from the mass balance, taking into account the effect of changes taking place in the inoculum itself (control test). For these tests, the initial concentrations of nitrogen forms are similar to those found in the mono-fermentation tests. A greater increase in ammonium nitrogen concentrations was found for the test with 80% inoculum than in the test with 20% (for the same feedstock). An increase in the removal efficiency of the dissolved organic nitrogen fraction (DON), and an increase for the colloidal (CON) and particulate organic nitrogen (PON) fractions after 28 days of co-digestion were observed. The trend of change was similar for 20% and 80% inoculum.

Methane and Hydrogen Sulfide Production from the Anaerobic Digestion of Fish Sludge from Recirculating Aquaculture Systems: Effect of Varying Initial Solid Concentrations

Recirculating aquaculture systems (RAS) are efficient at solid waste capture and collection but generate a concentrated waste stream. Anaerobic digestion (AD) could be one potential treatment option for RAS facilities. However, the concentration of organic matter in the sludge can significantly affect the biogas quality from AD. This study evaluated the effect of fish sludge (FS) solid concentration on biogas quality. Three FS treatments consisted of different initial total solid concentrations (1.5%, 2.5%, and 3.5%) from a mixture of sludge produced by Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Methane (CH4) production was measured, quantified, and normalized on a volatile solids (VS) basis. The highest solid concentration treatment produced 23% more CH4 than the lowest solid concentration (519 mL/g VS versus 422 mL/g VS, respectively). Peak CH4 production occurred on Day 7 for the lowest FS concentration (78.2 mL/day), while the highest FS concentration peaked on Day 11 (96 mL/day). Peak hydrogen sulfide (H2S) concentrations ranged from 1803–2074 ppm across treatments, signifying the requirement of downstream unit processes for H2S removal from biogas. Overall, this study demonstrated that increasing the FS concentration can significantly enhance CH4 production without affecting the stability of the digestion process.

Algorithm for Optimizing the Initial Conditions for a Chemical Reaction Based on a Kinetic Model

A numerical algorithm has been developed to search for the optimal values of the concentrations of chemical reaction reagents. The statement of the problem of determining the optimal initial concentrations of the initial substances on the basis of the kinetic model of the reaction, which is a system of ordinary differential equations, is formulated. To solve the problem, a genetic algorithm with real coding is given. The algorithm is modified taking into account the restriction on the values of the initial concentrations and the condition imposed on the total initial concentration of the reagents. A computational experiment was carried out for the reaction of the synthesis of benzyl butyl ether under the action of copper-containing catalysts. The initial concentrations of the initial substances are determined at which the highest values of the concentrations of the target reaction products are achieved.

Chlorine Removal from Water by Biochar Derived from Various Food Waste Natural Materials

The aim of this paper was to investigate the effectiveness of pyrolyzed low-cost food waste natural materials from the food industry on the removal of chlorine from water. Biochar was produced after pyrolysis at 850 oC from malt spent rootlets (MSR), walnut shells, and apricot, olive, carob and grape kernels. The biochars were characterized for their surface area, microporosity, functional groups and pH. Continuous flow column experiments were conducted at varying flow rates to evaluate the efficiency of biochars to remove free and total chlorine. The initial free and total chlorine concentrations in water fed to the columns were 2.0 and 2.2 mg/L, respectively. The chlorine removal of free and total chlorine of all materials tested ranged from 76 to 92% and 80 to 95%, respectively, with the MSR exhibiting the highest removal. MSR biochar was subjected to the highest cumulative water volume passed through the column (162 L/g) and exhibited the highest total chlorine removal capacity (6 to 330 mg/g). Olive kernel also reached high chlorine removal (99%), while apricot kernel, grape kernel, carob seed and pulp presented poor chlorine removals.

Influence of key operational parameters on biohydrogen production from fruit and vegetable waste via lactate-driven dark fermentation

This study aims at investigating the influence of operational parameters on biohydrogen production from fruit-vegetable waste (FVW) via lactate-driven dark fermentation. Mesophilic batch fermentations were conducted at different pH (5.5, 6.0, 6.5, 7.0, and non-controlled), total solids (TS) contents (5, 7, and 9%) and initial cell biomass concentrations (18, 180, and 1800 mg VSS/L). Higher hydrogen yields and rates were attained with more neutral pH values and low TS concentrations, whereas higher biomass densities enabled higher production rates and avoided wide variations in hydrogen production. A marked lactate accumulation (still at neutral pH) in the fermentation broth was closely associated with hydrogen inhibition. In contrast, enhanced hydrogen productions matched with much lower lactate accumulations (even it was negligible in some fermentations) along with the acetate and butyrate co-production but not with carbohydrates removal. At pH 7, 5% TS, and 1800 mg VSS/L, 49.5 NmL-H2/g VSfed and 976.4 NmL-H2/L-h were attained.

Two liquid phase partitioning bioreactor system for toxicant free water production from phthalates contaminated aqueous medium

Biodegradation of DMP (dimethyl phthalate) and DEP (diethyl phthalate) is a global environmental concern due to their endocrine disrupting nature. In the present study, biodegradation of DEP as the single substrate and a mixture of DMP and DEP as dual substrates were examined in a two-phase partitioning bioreactor (TPPB) using Cellulosimicrobium funkei. The TPPB system was run under batch and fed-batch modes of operation at different initial concentrations of DEP and mixture of DMP and DEP. Under the batch mode of operation, 93% degradation was achieved by C. funkei within 60 h with 38.75 mgL−1h−1 degradation rate. In the fed-batch system, complete degradation was observed up to 3500 mg/L total initial concentration of the phthalates (1500 mg/L DEP and 2000 mg/L DMP) within 24h. Phytotoxicity assessment of the treated water by seed germination and brine shrimp lethality assays revealed a germination index value of 86.17 and 13.33% brine shrimp mortality. Overall, this study revealed a very good potential of the TPPB system for detoxification of endocrine disrupting chemicals in the environment.

Chitosan-multilayered graphene oxide hybrid beads for Zn 2+ and metoprolol adsorption

Chitosan (CS) hydrogel beads and hybrid beads made of a blending of CS hydrogels and Multilayer Graphene Oxide (MGO) were synthesized. The hybrid beads were prepared by gelation in NaOH solution of a 1 wt% CS acid solution with addition of MGO at either 1.5 wt% or 3 wt% loading rates. Prepared beads were characterized by infrared spectroscopy, thermogravimetric analysis (TGA), scanning electron cryo-microscopy and Brunauer–Emmett–Teller (BET) specific surface area measurements. Zn 2+ and Metoprolol (MTP) adsorption kinetics and isotherms were studied on the pristine and hybrid CS hydrogel beads. The adsorption kinetics of Zn 2+ and MTP in hybrid beads is limited by the diffusion to the MGO sites depending on their accessibility. While pure CS is not efficient for the MTP adsorption, the Langmuir-type isotherms of the 3 wt% MGO hydrogel beads (dose: 5 mg/100 mL) show 163 mg·g -1 maximum adsorption uptake. The MTP adsorption kinetics and isotherm suggest a MTP trapping on the MGO anionic sites (carboxylate groups) by electrostatic interactions. The Zn 2+ adsorption capacities are the highest for the 3 wt% MGO hydrogel beads (236 mg·g -1 ), and only of 40 mg·g -1 for the pure CS beads. The presence of Zn 2+ adsorption sites in the hybrid bead, such as MGO carboxylate groups giving electrostatic interactions, and CS amine groups leading to complexation, provides synergic adsorption effects. The competitive adsorption of Zn 2+ with respect to MTP in equimolar mixture was observed on hybrid beads (dose: 200 mg/100 mL) at 2 mmol·L -1 initial total concentration. At pollutant initial total concentration lower than 1.5 mmol·L -1 , no competition occurs. The regeneration at pH 4 of the hybrid beads toward MTP or Zn 2+ adsorption was found to be 35–40% of the initial adsorption uptake for five adsorption/regeneration cycles.

Study of influence of initial concentration of heavy metal ions on the quality of fertization processing of electroplating sludge

Influence of the key parameter for the ferritization process - initial total concentration of heavy metal ions (СƩ) on the quality of galvanic sludge processing has been experimentally studied. It was determined, that at СƩ = 5.33 g/dm3 and electromagnetic pulse activation of the ferritization process, the lowest values ​​of residual concentrations of heavy metal ions in the purified solution were obtained: for iron – 0,10; nickel – 0,19; copper – 0,12; zinc – 0,10 mg/dm3. The obtained values ​​correspond to the average degree of extraction of these ions of 99,97%. The purified solution is suitable for reuse in electroplating facilities. As a result of structural studies of sediment samples, it was found that at total heavy metal concentration of 5,33 g/dm3 in the ferritization reaction mixture, regardless of the method of activating the process, phases containing crystalline ferromagnetic phases of ferrites (Ni, Cu, Zn) Fe2O4 exceeds 92%. The efficiency of resource-saving electromagnetic pulse activation of the reaction mixture in the ferritization process is confirmed. Using this method of activation, energy consumption is reduced by 1,5 times compared to thermal one. The proposed resource-saving ferritization technology prevents environmental pollution, ensures the rational use of raw materials and energy, as well as allows to obtain marketable products from industrial waste.