Sorption Of Pollutants Research Articles

Microbial extracellular polymeric substances in the environment, technology and medicine.

Microbial biofilms exhibit a self-produced matrix of extracellular polymeric substances (EPS), including polysaccharides, proteins, extracellular DNA and lipids. EPS promote interactions of the biofilm with other cells and sorption of organics, metals and chemical pollutants, and they facilitate cell adhesion at interfaces and ensure matrix cohesion. EPS have roles in various natural environments, such as soils, sediments and marine habitats. In addition, EPS are relevant in technical environments, such as wastewater and drinking water treatment facilities, and water distribution systems, and they contribute to biofouling and microbially influenced corrosion. In medicine, EPS protect pathogens within the biofilm against the host immune system and antimicrobials, and emerging evidence suggests that EPS can represent potential virulence factors. By contrast, EPS yield a wide range of valuable products that include their role in self-repairing concrete. In this Review, we aim to explore EPS as a functional unit of biofilms in the environment, in technology and in medicine.

Understanding requirements, limitations and applicability of QSAR and PTF models for predicting sorption of pollutants on soils: a systematic review

Understanding requirements, limitations and applicability of QSAR and PTF models for predicting sorption of pollutants on soils: a systematic review

Functional Bio-Based Polymeric Hydrogels for Wastewater Treatment: From Remediation to Sensing Applications.

In recent years, many researchers have focused on designing hydrogels with specific functional groups that exhibit high affinity for various contaminants, such as heavy metals, organic pollutants, pathogens, or nutrients, or environmental parameters. Novel approaches, including cross-linking strategies and the use of nanomaterials, have been employed to enhance the structural integrity and performance of the desired hydrogels. The evolution of these hydrogels is further highlighted, with an emphasis on fine-tuning features, including water absorption capacity, environmental pollutant/factor sensing and selectivity, and recyclability. Furthermore, this review investigates the emerging topic of stimuli-responsive smart hydrogels, underscoring their potential in both sorption and detection of water pollutants. By critically assessing a wide range of studies, this review not only synthesizes existing knowledge, but also identifies advantages and limitations, and describes future research directions in the field of chemically engineered hydrogels for water purification and monitoring with a low environmental impact as an important resource for chemists and multidisciplinary researchers, leading to improvements in sustainable water management technology.

Properties and Possibilities of Using Biochar Composites Made on the Basis of Biomass and Waste Residues Ferryferrohydrosol Sorbent.

Biochar enriched with metals has an increased potential for sorption of organic and inorganic pollutants. The aim of the research was to identify the possibility of using biochar composites produced on the basis of waste plant biomass and waste FFH (ferryferrohydrosol) containing iron atoms, after CO2 capture. The composites were produced in a one-stage or two-stage pyrolysis process. Their selected properties were determined as follows: pH, ash content, C, H, N, O, specific surface area, microstructure and the presence of surface functional groups. The produced biochar and composites had different properties resulting from the production method and the additive used. The results of experiments on the removal of methylene blue (MB) from solutions allowed us to rank the adsorbents used according to the maximum dye removal value achieved as follows: BC1 (94.99%), B (84.61%), BC2 (84.09%), BC3 (83.23%) and BC4 (83.23%). In terms of maximum amoxicillin removal efficiency, the ranking is as follows: BC1 (55.49%), BC3 (23.51%), BC2 (18.13%), B (13.50%) and BC4 (5.98%). The maximum efficiency of diclofenac removal was demonstrated by adsorbents BC1 (98.71), BC3 (87.08%), BC4 (74.20%), B (36.70%) and BC2 (30.40%). The most effective removal of metals Zn, Pb and Cd from the solution was demonstrated by BC1 and BC3 composites. The final concentration of the tested metals after sorption using these composites was less than 1% of the initial concentration. The highest increase in biomass on prepared substrates was recorded for the BC5 composite. It was higher by 90% and 54% (for doses of 30 g and 15 g, respectively) in relation to the biomass growth in the soil without additives. The BC1 composite can be used in pollutant sorption processes. However, BC5 has great potential as a soil additive in crop yield and plant growth.

Desorption of Polycyclic Aromatic Hydrocarbons from Microplastics in Human Gastrointestinal Fluid Simulants-Implications for Exposure Assessment.

Microplastics have been detected in various food types, suggesting inevitable human exposure. A major fraction may originate from aerial deposition and could be contaminated by ubiquitous pollutants such as polycyclic aromatic hydrocarbons (PAHs). While data on the sorption of pollutants to microplastics are abundant, the subsequent desorption in the gastrointestinal tract (GIT) is less understood. This prompted us to systematically investigate the release of microplastics-sorbed PAHs at realistic loadings (44-95 ng/mg) utilizing a physiology-based in vitro model comprising digestion in simulated saliva, gastric, and small and large intestinal fluids. Using benzo[a]pyrene as a representative PAH, desorption from different microplastics based on low density polyethylene (LDPE), thermoplastic polyurethanes (TPUs), and polyamides (PAs) was investigated consecutively in all four GIT fluid simulants. The cumulative relative desorption (CRD) of benzo[a]pyrene was negligible in saliva simulant but increased from gastric (4 ± 1% - 15 ± 4%) to large intestinal fluid simulant (21 ± 1% - 29 ± 6%), depending on the polymer type. CRDs were comparable for ten different microplastics in the small intestinal fluid simulant, except for a polydisperse PA-6 variant (1-10 μm), which showed an exceptionally high release (51 ± 8%). Nevertheless, the estimated contribution of microplastics-sorbed PAHs to total human PAH dietary intake was very low (≤0.1%). Our study provides a systematic data set on the desorption of PAHs from microplastics in GIT fluid simulants.

A review of crop residue-based biochar as an efficient adsorbent to remove trace elements from aquatic systems

AbstractCrop residue-based biochar (CRB) has shown great potential for removing trace elements (TEs) from aquatic matrices. Despite the increasing interest in this area, no review has focused specifically on the efficacy of CRB for TEs removal in aquatic environments. This comprehensive review examines the global TEs water contamination status with an emphasis on their sources, compositional metrics for crop residue feedstock (proximate, ultimate, and lignocellulosic properties), and the potential use of CRB for TEs removal in aquatic media. It also evaluates the factors that affect the ability of CRB to remove TEs, such as feedstock type, production conditions, water pH, background electrolytes, water temperature, CRB/water ratio, and underlying pollutant sorption mechanisms. This review also discusses the practical applications of CRB in real water samples and engineering considerations for designing CRB with improved physicochemical properties, treatment efficiencies, and regeneration abilities. Additionally, the cost–benefit and economic assessment of CRB, challenges, and future research directions related to CRB are highlighted to promote research on this sustainable source of biochar. By elucidating the prospects of CRB as an adsorbent, this review emphasizes the need for continued research on its practical implications for environmentally relevant pollutant concentrations. Graphical Abstract

Impact of pyrolysis process conditions on the structure of biochar obtained from apple waste

Biochar is an eco-friendly carbon material whose properties allow it to be used as a sorbent for wastewater treatment or soil remediation. The paper presents the results of research related to the pyrolysis process of apple waste after supercritical CO2 extraction with the simultaneous use of physical activation. The research assessed the influence of the temperature of the pyrolysis process and steam activation on the structural properties of the obtained biochar, i.e. specific surface, porous structure, and presence of functional groups. The results obtained confirmed that lower temperature pyrolysis produces biochar characterised by the presence of functional groups and ordered structure. On the other hand, high temperature pyrolysis with simultaneous steam activation determines microporosity and high values of the specific surface area. Taking into consideration pollutant sorption mechanisms (physical and chemical sorption), the obtained biochar materials can be used as sorbents in water and wastewater treatment.

Application of kinetic models to study the sorption rate in the ‘ammonium ions–calcined sorbent’ system

This study examines sorption kinetics for the extraction of ammonium ions from an aqueous solution under static conditions using 5 g of sorbent. The sorbent was obtained by calcining ash and slag waste accumulated in the ash dump following hydraulic ash removal. The initial concentrations of ammonium ions in the model solutions were 5, 20, 50 and 100 mg/dm3. The volume of the model solution was 50 cm3. For each initial concentration, the kinetic curves of the ammonium ion sorption at the sorption duration of 10, 30, 60, 90, 120, 150 and 180 min were obtained. The kinetic curves were processed using the Lagergren (pseudo-first order), Ho and McKay (pseudo-second order), Morris-Weber (diffusion) and Elovich kinetic equations. It was demonstrated that all kinetic equations adequately describe the experimental data. The linear correlation of the equations was given. The Boyd equation was used to determine the limiting stage in the Morris–Weber model. It was established that the external diffusion mechanism is limiting for the sorption of ammonium ions by a calcined sorbent. The Lagergren model, with a coefficient of determination R2 of 0.9801–0.9949, best described the experimental data on sorption kinetics. Sorption rate curves as a function of the adsorption value and sorption time were given. The latter are described by exponential and polynomial dependence according to the Lagergren model, polynomial dependence according to the Ho and McKay model and exponential dependence according to the Morris–Weber and Elovich models. The sorption rate was the highest at the initial stage of sorption for all dependencies, which is consistent with previous studies on the sorption of pollutants from aqueous solutions using various sorbents.

Assessment of the effect of peat soil on the content of mobile forms of heavy metals and allelotoxicity in urbanized soils under moisture-loving plants at the Ecological Station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy

The article presents the results of studies on the sorption of pollutants by moisture-loving plants when using peat soil under different anthropogenic loads. The comparative cultivation of moisture-loving plants on sod-podzolic soil, typical for this area, and on peat soil revealed their specificity in the sorption of heavy metals: there was a decrease in the content of lead and copper in peat soil under moisture-loving plants. In typical sod-podzolic soil under moisture-loving plants the opposite dynamics was observed. As for the zinc content, it was found that it increased in peat soil under moisture-loving plants, with the exception of reed. The experiment was conducted on the territory of the Ecological Station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy in Moscow in 2019‑2022. Thus, moisture-loving plants grown on peat soil as a substrate can be used to reduce the content of mobile forms of heavy metals (lead and copper) in urbanized soils.

Magnetic luffa/graphene/CuFe2O4 sponge for efficient oil/water separation

In this study, a novel magnetic composite material comprising luffa sponge derived graphene aerogel embedded with hollow CuFe2O4 nanospheres (LGN) is successfully synthesised for the first time by a clean and low-cost one-step solvothermal electrostatic co-assembly method. The resultant LGN aerogel exhibits superhydrophobic and superoleophilic properties with the water and oil contact angles of 162.1° and 0°, respectively, along with magnetic properties characterized by the saturation magnetization of 51.6 emu/g, and a large specific surface area of 218.8 m2/g. The saturation sorption capacity of LGN for organic solvents/oil is found to be in the range of 47.6–86.8 g/g, exhibiting an excellent oil/water emulsion separation ability. Through the capillary action, oil and organic solvents spontaneously penetrate into the interior of the aerogel, while the superhydrophobic surface prevents water from entering, thereby enabling the separation of oil and water. These characteristics enable the real-time sorption of organic pollutants from water, with the capability of exhausted sorbent being regenerated. Notably, even after 20 sorption-volatilisation cycles, the saturated sorption capacity of LGN remains high at the 92.2 % of the initial value, demonstrating a remarkable recycling performance. In addition, LGN can exhibit an oriented sorption performance by controlling the applied magnetic field, enabling sorbent recycling even under extreme environmental conditions. Such an effective strategy offers a new route to high value utilisation of biomass waste with significant potential in the field of oil spill treatment.

Water column organic carbon composition as driver for water-sediment fluxes of hazardous pollutants in a coastal environment

The environmental fate of hazardous hydrophobic pollutants in the marine environment is strongly influenced by organic carbon (OC) cycling. As an example, the seasonality in primary production impacts both water column OC quantity and quality, which may influence pollutant mass transport from the water column to the sediment. This study aims to better understand the role of water column OC variability for the fate of pollutants in a near-coastal area. We conducted an in situ sampling campaign in the coastal Baltic Proper during two seasons, summer and autumn. We used polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) as model compounds, as they represent a wide range in physicochemical properties and are ubiquitous in the environment. Freely dissolved, and OC-bound concentrations were studied in the water column and surface sediment. We found stronger sorption of pollutants to suspended particulate matter (SPM) during the summer compared to the autumn (average 0.6 and 0.9 log unit higher particle-water partition coefficients during summer for PAHs and PCBs). Our data suggest that stronger sorption mirrors a compositional change of the OC towards higher contribution of labile OC during the summer, characterized by two times higher fatty acid and 24% higher dicarboxylic acids in SPM during summer. High concentrations of OC in the water column during the autumn resulted in increased SPM-mediated sinking fluxes of pollutants. Our results suggest that future changes in primary production are prone to influence the bioavailability and mobility of pollutants in costal zones, potentially affecting the residence time of these hazardous substances in the circulating marine environment.

Study of the dependence of component composition - degree of wastewater purification by adsorbents based on plant raw materials to control the content of priority pollutants in water bodies

In conditions of intensive development of industrial and agricultural production, measures aimed at protecting the hydrosphere from harmful substances are becoming increasingly important every year. Water purification using the sorption method and water treatment is one of the most common technological processes. Almost unlimited reserves of sorbents of natural origin, their low cost, and fairly high adsorption and ion-exchange properties make their use advisable. Sorbents developed on the basis of available secondary plant raw materials show high efficiency and open up the possibility of their practical use in solving environmental problems. New sorbents based on plant raw materials have been developed, their structure and morphology have been studied in order to identify the absorption capacity and effectiveness of use as oil sorbents. Studies of the kinetics and dynamics sorption of oil pollutants confirm the effectiveness of mentioned sorbents and sorption purification technology can be used for environmental monitoring of water bodies.

Nanopolystyrene size effect and its combined acute toxicity with halogenated PAHs on Daphnia magna

Nanoplastics (NPs, diameter <1 μm) not only have toxicity but also change the toxicity of other pollutants in water. To date, the nanopolystyrene (nano-PS) size effect and its combined toxicity with halogenated polycyclic aromatic hydrocarbons (HPAHs) remain unclear. In this study, the single toxicity, combined toxicity, and mode of action of the binary mixture of polystyrene (PS) and HPAH were examined. At the same time, the nano-PS size effect on combined toxicity was also discussed. According to our results, the 48 h acute toxicity test results showed that 30 nm PS was highly toxic (EC50–48 h = 1.65 mg/L), 200 nm PS was moderately toxic (EC50–48 h = 17.8 mg/L), and 1 μm PS was lowly toxic (EC50–48 h = 189 mg/L). The NP toxicity decreased with increasing size. HPAHs were highly toxic substances to Daphnia magna (EC50–48 h = 0.12–0.22 mg/L). The mode of action of PS and HPAHs was antagonistic according to the toxicity unit method (TU), additive index method (AI), and mixture toxicity index method (MTI). The size effect of nano-PS operates via two mechanisms: the inherent toxicity of nano-PS and the sorption of pollutants by nano-PS. The former impacts the combined toxicity more than the latter. In the binary mixed system, the larger the particle size and the higher the proportion of NPs in the system, the less toxic the system was. Linear interpolation analysis can be used to predict the combined toxicity of a mixed system with any mixing ratio.

Impacts of multi-pollutants on sulfonamide antibiotic removal from water matrices using layered double hydroxide sorbents

Remediation of sulfamethoxazole (SMX) present in the aqueous environment requires the development of new advanced wastewater treatment technologies, crucial to reduce the toxicity of such pollutants to the environment, supporting urban water reuse. Continuously synthesised layered double hydroxides (LDH) have been applied as a sorbent material for the removal of SMX from water. No equilibrium uptake of SMX was observed from any water matrix. However, an unusual sorption/release behaviour of SMX was observed in the presence of Mg2Al-NO3-LDH, influenced by the characteristics of the water matrix. A maximum SMX removal percentage of 34.7% was reached within 10 min, from ultrapure water, followed by release of SMX back into solution over the following 24 h. Further, Mg2Al-NO3-LDH is shown to release NO3- into all water matrices. It is proposed that NO3- disrupts the SMX-LDH interactions, resulting in release of SMX from the LDH. No initial SMX sorption was observed onto Mg2Al-NO3-LDH when wastewater effluent was the water matrix, likely due to competition for sorption sites on the LDH with multiple pollutants, including metals and additional anionic nutrients, present in the wastewater. This work illustrates the potential for relationships between the sorbent material and water matrix interactions on pollutant sorption behaviour. In addition, the findings highlight the importance of conducting removal experiments at realistic environmental conditions to ensure development of suitable sorbent materials for pollutant remediation.

Microplastic effects in aquatic ecosystems with special reference to fungi–zooplankton interaction: identification of knowledge gaps and prioritization of research needs

Microplastics (MPs) are plastic particles &amp;lt;5 mm in size, that end up ultimately in marine and freshwater ecosystems, adversely affecting various ecological functions. With the multifaceted roles of fungi and their diverse modes of interaction such as saprobic, epibiotic, endobiotic, parasitic, and symbiotic or being a nutritionally enriched food source in aquatic ecosystems, the effect of MPs on fungi–plankton interactions is still less explored. Properties of MPs such as (i) size range similar to those of microeukaryotes, (ii) substrate for unique microbiota, (iii) ability to be transported from the source to faraway waterbodies, and (iv) sorption of pollutants, have adverse effects on various guilds of ecological organization. MPs also tend to alter nutrient cycling and inhibit efficient energy transfer through microbial and mycoloop in an ecosystem. This paper comprehensively reviews the effect of MPs at the population and community level on the complex ecological (fungi–phytoplankton–zooplankton) interactions with an emphasis on the role of fungi in the aquatic ecosystem. Examination of existing literature revealed that MPs can interfere in ecosystem functioning by acting in synergy with fungi, while antagonistically affecting the community and vice-versa. Herein, we explore current understanding of the effect of MPs on major components of microbial and mycoloop in the marine food web, elaborating MPs-mediated changes in the ecosystem functioning, identifying research gaps, and highlighting the need for future research.

Insights into the effect of hydrochar-derived dissolved organic matter on the sorption of diethyl phthalate onto soil: A pilot mechanism study

Biowaste-derived hydrochar is an emerging close-to-natural product and has shown promise for soil improvement and remediation, but the environmental behavior of the dissolved organic matter released from hydrochar (HDOM) is poorly understood. Focusing on the typical mulch film plasticizer diethyl phthalate (DEP), we investigated the effect of HDOM on the sorption behavior of DEP on soil. The relatively low concentration of HDOM (10 mg L−1, 25 mg L−1) decreases the sorption quantity of DEP on soil, while it increases by a relatively high concentration, 50 mg L−1. The transformation from multilayer to monolayer sorption of DEP on soil occurs as the concentration of HDOM increases. The tryptophan-like substance is the main component of HDOM sorbed to soil, reaching 49.82 %, and results in competition sorption with DEP. The soil pores are blocked by HDOM, which limits the pore filling and mass transfer of DEP, but partitioning is significantly enhanced. The surface functional groups in HDOM are similar to those in soil, and chemical sorption, mainly composed of hydrogen bonding, exists but is not significantly strengthened. We identified the specific impact of HDOM on the sorption of organic pollutants on soil and provide new insights into the understanding of the environmental behavior of hydrochar.

Assessing pollutant sorption efficiency of modified and unmodified biochar with Bacillus cereus on contaminated lake water: implications for Oryza sativa seedling and Artemia franciscana larvae viability

Assessing pollutant sorption efficiency of modified and unmodified biochar with Bacillus cereus on contaminated lake water: implications for Oryza sativa seedling and Artemia franciscana larvae viability

Carbon isotope effects in the sorption of chlorinated ethenes on biochar and activated carbon

As an alternative to activated carbon, biochar is a promising, environmentally friendly sorbent that can be used to remove organic groundwater pollutants, such as chlorinated ethenes (CEs). Stable isotope fractionation in biofilters is used to quantify pollutant degradation and to distinguish degradation from pollutant sorption on e.g. biochar. However, the sorption of CEs on biochar, and the potential abiotic fractionation processes remain to be tested. The sorption process of CEs and ethene on activated carbon and biochar was investigated with regard to the isotope effects for the differentiation from microbial degradation processes. Results from physical and chemical characterization of biochar indicated that biochar feedstock and pyrolysis conditions determined sorption performance depending on the surface chemistry and the pore size distribution of the coarse sorbent particles. The sorption capacity of the activated carbon was significantly higher with highly chlorinated ethenes, but similar to the biochars with low chlorination. Apparent carbon isotope fractionation factors (ε) of +0.1 to −4.4 ‰ were found above measurement uncertainties of GC/IRMS. The extent of isotope enrichment of the 13C bearing isotopologues in the residual aqueous phase (ε < 0) was characteristic for individual pairs of pollutant and sorbent material and could be related to pore-filling processes limited by the micropore size distribution of sorbent materials and the chemical properties of sorbed pollutants. Especially the large isotope fractionation during the sorption of ethene led to the assumption that diffusion processes within the pore matrix of the sorbent particles contributed to the observed isotope effects, but should still be considered a property of sorption. Concluding on the results indicated that sorption processes can have a significant contribution to carbon isotope fractionation in CEs and ethene. These should not be neglected in the evaluation of biofilters for groundwater purification, in which CEs are simultaneously degraded by microbes.

Exploring synergistic effects in physical-chemical activation of Acorus calamus for water treatment solutions

The research proposed a novel method of obtaining sorption material from readily available Acorus calamus biomass through a combination of physical and chemical activation processes. The material with the highest specific surface area (1652 m2 g−1) was obtained by physical activation with CO2, followed by chemical activation with KOH. Reversing the order of activation methods resulted in a lower specific surface area (1014 m2 g−1) of the carbon sample. Chemical activation produced activated carbon with a surface area of 1066 m2 g−1-, while physical activation produced 390 m2 g−1. This confirms the synergistic effect of combining the two activation methods for biocarbon. It was observed that physical activation with CO2 generates a diverse range of pores, including meso- and macropores, while chemical activation induces the formation of micropores. In contrast, reversing the order of these processes leads to the degradation of the porous structure. The application of physical-chemical activation with synergistic effects represents a significant advancement in producing high-quality activated biocarbon for various applications, such as wastewater treatment and energy storage. The combination of the two activation methods resulted in a synergistic effect, leading to the production of carbon material of higher quality. Additionally, the diversified pore sizes will enable the sorption of various pollutants in the aquatic environment and air pollutants, where gas particles are much smaller.

Pectin hydrogels modified with montmorillonite: Case studies for the removal of dyes and herbicides from water

Hydrogels were synthesized with pectin and modified with montmorillonite for case studies involving the removal of dyes and herbicides from water. Methylene blue and 2,4-dichlorophenoxyacetic acid (2,4-D) were used as model pollutants. Fourier-transform infrared spectroscopy performed before and after the pollutant sorption studies enabled the identification of chemical groups in the structure of the hydrogels and interactions with each pollutant in the aqueous medium. Thermogravimetric analysis, differential thermogravimetry and differential scanning calorimetry were employed to determine thermal events in the polymeric networks of the hydrogels before and after pollutant sorption. Scanning electron microscopy was employed to evaluate the hydrogel morphologies before and after the sorption studies. The water diffusion mechanisms and point of zero charge in each hydrogel varied according to the type of aqueous medium. Moreover, the pollutant sorption capacity of the hydrogels varied as a function of the sorption time, pH and temperature of the aqueous solution as well as the initial concentration of the pollutant. The Redlich-Peterson and Sips isotherms had the best fit to the experimental data, indicating that the sorption of methylene blue and 2,4-D tends to occur by simultaneous multi-site interactions and the formation of a monolayer. The thermodynamic and kinetic data complemented the isotherm data and assisted in the definition of real-world application strategies. Composite hydrogels with lower montmorillonite content are potentially better removers of drugs, food dyes, sugar substitutes and herbicides from water compared to conventional hydrogels not modified with montmorillonite. Overall, these hydrogels could be reused for three successive cycles of sorption after the recovery with either hydrochloric acid or ethanol.