Break oily water emulsion during petroleum enhancing production processes using green approach for the synthesis of SnCuO@FeO nanocomposite from microorganisms.

The aim of this work was to synthesize a green nanoparticle SnCuO@FeO nanocomposite core-shell to break oily water emulsions during petroleum-enhancing production processes as an alternative to chemical and physical processes. In this study, eight bacterial isolates (MHB1-MHB8) have been isolated from tree leaves, giant reeds, and soil samples. The investigation involved testing bacterial isolates for their ability to make FeO nanoparticles and choosing the best producers. The selected isolate (MHB5) was identified by amplification and sequencing of the 16S rRNA gene as Bacillus paramycoides strain OQ878685. MHB5 produced the FeO nanoparticles with the smallest particle size (78.7 nm) using DLS. XRD, FTIR, and TEM were used to characterize the biosynthesized nanoparticles. The jar experiment used SnCuO@FeO with different ratios of Sn to CuO (1:1, 2:1, and 3:1) to study the effect of oil concentration, retention time, and temperature. The most effective performance was observed with a 1:1 ratio of Sn to CuO, achieving an 85% separation efficiency at a concentration of 5 mg/L, for a duration of 5 min, and at a temperature of 373 K. Analysis using kinetic models indicates that the adsorption process can be accurately described by both the pseudo-first-order and pseudo-second-order models. This suggests that the adsorption mechanism likely involves a combination of film diffusion and intraparticle diffusion. Regarding the adsorption isotherm, the Langmuir model provides a strong fit for the data, while the D-R model indicates that physical interactions primarily govern the adsorption mechanism. Thermodynamic analysis reveals a ∆H value of 18.62 kJ/mol, indicating an exothermic adsorption process. This suggests that the adsorption is a favorable process, as energy is released during the process. Finally, the synthesized green SnCuO@FeO nanocomposite has potential for use in advanced applications in the oil and gas industry to help the industry meet regulatory compliance, lower operation costs, reduce environmental impact, and enhance production efficiency.

In situ single iron atom doping on Bi2WO6 monolayers triggers efficient photo-fenton reaction.

Developing an efficient photocatalytic system for hydrogen peroxide (H2O2) activation in Fenton-like processes holds significant promise for advancing water purification technologies. However, challenges such as high carrier recombination rates, limited active sites, and suboptimal H2O2 activation efficiency impede optimal performance. Here we show that single-iron-atom dispersed Bi2WO6 monolayers (SIAD-BWOM), designed through a facile hydrothermal approach, can offer abundant active sites for H2O2 activation. The SIAD-BWOM catalyst demonstrates superior photo-Fenton degradation capabilities, particularly for the persistent pesticide dinotefuran (DNF), showcasing its potential in addressing recalcitrant organic pollutants. We reveal that the incorporation of iron atoms in place of tungsten within the electron-rich [WO4]2- layers significantly facilitates electron transfer processes and boosts the Fe(II)/Fe(III) cycle efficiency. Complementary experimental investigations and theoretical analyses further elucidate how the atomically dispersed iron induces lattice strain in the Bi2WO6 monolayer, thereby modulating the d-band center of iron to improve H2O2 adsorption and activation. Our research provides a practical framework for developing advanced photo-Fenton catalysts, which can be used to treat emerging and refractory organic pollutants more effectively.

Effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork grown in Korea.

The effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork (Qv VC) were examined and compared with those of Quercus suber reproduction cork (Qs RC). The water treatment was conducted at 100 °C for 1 h. Qv VC showed a significantly higher dimensional change in the three directions and lower weight loss than Qs RC by boiling water treatment. Untreated and boiled Qv VC showed higher density, air-dried moisture content, red/green (a*) and yellow/blue (b*) chromaticity, overall color change, shrinkage in all three directions, moisture adsorption on the entire surface, and swelling per 1% moisture content than untreated and boiled Qs RC. However, the lightness (L*) and water absorption on each surface were higher for Qs RC than for Qv VC. Moisture adsorption on each surface was comparable before and after heat treatment for both species. After boiling water treatment, the air-dried moisture content, dimensions, volume shrinkage, water absorption, and moisture adsorption on each surface and the entire surface increased, whereas L*, a*, b*, and swelling per 1% moisture content decreased. The results of the present study could be useful for further utilization of Qv cork growing in Korea.

Recycling drinking water treatment sludge in construction and building materials: A review.

Drinking water treatment sludge (DWTS) is a by-product of water treatment, and it is difficult to recycle to high value and poses potential environmental risks. Recycling DWTS into cement-based materials is an effective measure to achieve its high-volume utilization and reduce its environmental load. DWTS is rich in silica-alumina phases and has potential pozzolanic activity after drying, grinding and calcination, giving it similar properties to traditional supplementary cementitious materials. Adjusting the sludge production process and coagulant type will change its physical and chemical properties. Adding a small amount of DWTS can generate additional hydration products and refine the pore structure of the cement sample, thus improving the mechanical properties and durability of the sample. However, adding high-volume DWTS to concrete causes microstructural deterioration, but it is feasible to use high-volume DWTS to produce artificial aggregates, lightweight concrete, and sintered bricks. Meanwhile, calcined DWTS has similar compositions to clay, which makes it a potential raw material for cement clinker production. Cement-based materials can effectively solidify heavy metal ions in DWTS, and alkali-activated binders, magnesium-based cement, and carbon curing technology can further reduce the risk of heavy metal leaching. This review provides support for the high-value utilization of DWTS in cement-based materials and the reduction of its potential environmental risks.

Environmental iodine as a natural iodine intake in humans and environmental pollution index: a scientometric and updated mini review.

Although almost a third of the world's population is exposed to iodine deficiency (ID), and supplementation programs such as enriching table salt have been carried out or are being carried out at the global and national level, in many regions of the world, people are facing an increase in iodine intake, which is mainly due to the presence of large amounts of iodine in water, soil, agricultural products, or high consumption of seafood. Published articles were indexed in the Scopus database (from 2000 to 1 April 2023) were reviewed and analyzed by VOSviewer software. The results showed the growing interest of researchers over the last 20 years in environmental iodine intake. The results of this study can have a significant impact on the planning and policy-making of relevant officials and communities to supply the needed iodine.

A review of remediation technologies for uranium-contaminated water.

Uranium is a naturally existing radioactive element present in the Earth's crust. It exhibits lithophilic characteristics, indicating its tendency to be located near the surface of the Earth and tightly bound to oxygen. It is ecotoxic, hence the need for its removal from the aqueous environment. This paper focuses on the variety of water treatment processes for the removal of uranium from water and this includes physical (membrane separation, adsorption and electrocoagulation), chemical (ion exchange, photocatalysis and persulfate reduction), and biological (bio-reduction and biosorption) approaches. It was observed that membrane filtration and ion exchange are the most popular and promising processes for this application. Membrane processes have high throughput but with the challenge of high power requirements and fouling. Besides high pH sensitivity, ion exchange does not have any major challenges related to its application. Several other unique observations were derived from this review. Chitosan/Chlorella pyrenoidosa composite adsorbent bearing phosphate ligand, hydroxyapatite aerogel and MXene/graphene oxide composite has shown super-adsorbent performance (>1000 mg/g uptake capacity) for uranium. Ultrafiltration (UF) membranes, reverse osmosis (RO) membranes and electrocoagulation have been observed not to go below 97% uranium removal/conversion efficiency for most cases reported in the literature. Heat persulfate reduction has been explored quite recently and shown to achieve as high as 86% uranium reduction efficiency. We anticipate that future studies would explore hybrid processes (which are any combinations of multiple conventional techniques) to solve various aspects of the process design and performance challenges.

Effective microorganism water treatment method for rapid eutrophic reservoir restoration.

Since reservoirs perform many important functions, they are exposed to various types of unfavorable phenomena, e.g., eutrophication which leads to a rapid growth of algae (blooms) that degrade water quality. One of the solutions to combat phytoplankton blooms are effective microorganisms (EM). The study aims to evaluate the potential of EM in improving the water quality of the Turawa reservoir on the Mala Panew River in Poland. It is one of the first studies providing insights into the effectiveness of using EM in the bioremediation of water in a eutrophic reservoir. Samples for the study were collected in 2019-2021. The analysis showed that EM could be one of the most effective methods for cleaning water from unfavorable microorganisms (HBN22, HBN36, CBN, FCBN, FEN) - after the application of EM, a reduction in their concentration was observed (from 46.44 to 58.38% on average). The duration of their effect ranged from 17.6 to 34.1 days. The application of EM improved the trophic status of the Turawa reservoir, expressed by the Carlson index, by 7.78%. As shown in the literature review, the use of other methods of water purification (e.g., constructed wetlands, floating beds, or intermittent aeration) leads to an increase in the effectiveness and a prolongation of the duration of the EM action. The findings of the study might serve as a guide for the restoration of eutrophic reservoirs by supporting sustainable management of water resources. Nevertheless, further research should be conducted on the effectiveness of EM and their application in the remediation of eutrophic water reservoirs.

An XAS study of Hg(II) sorption to Al-based drinking water treatment residuals.

Drinking water treatment residuals (DWTRs) are produced from the coagulation and flocculation processes in conventional drinking water treatment. The abundant metal oxide content of these materials resulting from the use of coagulants, like alum and ferric chloride, has driven strong research interest into the reuse of DWTRs as sorptive materials. Using a suite of aluminum-based DWTRs, we provide new insights into Hg(II) sorption mechanisms. Experiments performed at circum-neutral pH show that sorption capacities are related to the amount of organic carbon/matter present in DWTRs. We found that carbon rich samples can scavenge about 9000 mg/kg of Hg, in contrast to 2000 mg/kg for lime based DWTRs. X-ray absorption spectroscopy (XAS) at the Hg L3 edge further characterizes mercury coordination. X-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) results point to a partial association of mercury with sulfur at low mass loadings, transitioning to a full association with oxygen/carbon at higher concentrations of sorbed Hg(II) and in DWTRs with limited sulfur content. These results suggest that sorption of Hg(II) is primarily controlled by the carbon/organic matter fraction of DWTRs, but not by the coagulants.

Adsorption of uranium (VI) complexes with polymer-based spherical activated carbon.

Adsorption processes with carbon-based adsorbents have received substantial attention as a solution to remove uranium from drinking water. This study investigated uranium adsorption by a polymer-based spherical activated carbon (PBSAC) characterised by a uniformly smooth exterior and an extended surface of internal cavities accessible via mesopores. The static adsorption of uranium was investigated applying varying PBSAC properties and relevant solution chemistry. Spatial time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to visualise the distribution of the different uranium species in the PBSAC. The isotherms and thermodynamics calculations revealed monolayer adsorption capacities of 28-667 mg/g and physical adsorption energies of 13-21 kJ/mol. Increasing the surface oxygen content of the PBSAC to 10 % enhanced the adsorption and reduced the equilibrium time to 2 h, while the WHO drinking water guideline of 30 µgU/L could be achieved for an initial concentration of 250 µgU/L. Uranium adsorption with PBSAC was favourable at the pH 6-8. At this pH range, uranyl carbonate complexes (UO2CO3(aq), UO2(CO3)22-, (UO2)2CO3(OH)3-) predominated in the solution, and the ToF-SIMS analysis revealed that the adsorption of these complexes occurred on the surface and inside the PBSAC due to intra-particle diffusion. For the uranyl cations (UO22+, UO2OH+) at pH 2-4, only shallow adsorption in the outermost PBSAC layers was observed. The work demonstrated the effective removal of uranium from contaminated natural water (67 µgU/L) and meeting both German (10 µgU/L) and WHO guideline concentrations. These findings also open opportunities to consider PBSAC in hybrid treatment technologies for uranium removal, for instance, from high-level radioactive waste.

New method of producing a more efficient coagulant for the treatment of water from seeds of moringa oleifera.

The coagulation is essential in raw water treatment. The most used coagulants are often of chemical origin and expensive and their use generates non-biodegradable residues. This is why innovative studies on the synthesis of natural coagulants based on plant extracts are very important. This study presents a new method of producing a coagulant for the treatment of water from seeds of moringa oleifera. The application of the new method is done in several steps: Harvesting moringa oleifera seeds, shelling, crushing the seeds, extracting oil from moringa oleifera powder, extracting salts from powder from moringa seeds oleifera, microfiltration with a 0.2 µm filter and lyophilization which gives the final product in dry form. We used the resulting product for coagulation of lake water with an initial turbidity of 40 NTU. This treatment reduced the turbidity of the water by almost 95 % when we used 0.7 mg of this coagulant per liter of water. Moringa has previously been used to produce coagulant but the peculiarity of this study is that it takes a very small amount of the synthesized product to effectively treat water. -The results of this research work have shown that the coagulant produced rom the seeds of Moringa oleifera can be used effectively for the treatment of surface water.-The residual turbidity obtained after the treatment of lake water with the coagulant produced was in accordance with the drinking water standard according to the World Health Organization (WHO) (less than 5 NTU).-The coagulant produced by this new method from moringa oleifera seed is an alternative to aluminum sulfate coagulant for water treatment.

Fabrication and optimization of curcumin-multiwalled carbon nanotube (C-MWCNT) conjugate reinforced electrospun polyacrylonitrile membrane for water treatment applications.

In the recent times, one of the most crucial tasks related to water resources is the treatment of polluted water. This study reports the development of a functionalized nanofibrous membrane with enhanced filtration performance, heavy metal removal, and photocatalytic dye degradation for the effective treatment of contaminated water. The nanofibrous mats were developed by the process of electrospinning using a polymeric solution of polyacrylonitrile (PAN) reinforced with curcumin-multiwalled carbon nanotube (C-MWCNT) conjugate. The experimental trials for membrane fabrication were adapted based on the design of experiments (DoE) approach by making use of the Box-Behnken design (BBD) for a three-variable system, a component of response surface methodology (RSM). The three variable parameters selected for optimization of the electrospinning process were the dopant concentration (in weight percentage), the flow rate (in millilitre per hour), and the spinning time (in hours), respectively, and a total of 15 fibrous membranes were fabricated. The SEM analysis of the fabricated membranes revealed alterations in the surface morphology of the fibrous mats with variations in the electrospinning parameters. The infrared spectrum of the fibrous mats, validated the incorporation C-MWCNT conjugate in PAN, thereby confirming the formation of PAN/C-MWNCNT membrane. The mean flow pore size and breaking force of the PAN/C-MWCNT membranes was also obtained using a universal testing machine (UTM) and porometer, respectively. To choose the best membrane for efficient filtration experiments, the performance of each of the prepared membranes was assessed in terms of solute rejection percentage (SR%), permeate flux (PF), and pure water flux (PWF). The statistical analysis of the assessed parameters in accordance with the membranes prepared was done using the MINITAB software, and the three-dimensional (3D) surface plots were constructed using the STATISTICA software to visualize and validate the relation between each of the electrospinning parameters and the corresponding membrane performance characteristics. Similarly, the potential of the electrospun membranes for efficient heavy metal ion removal and photocatalysis were also tested independently and the optimal electrospinning parameters were determined for the same. Based on the results, it was observed that the PAN/C-MWCNT membranes could serve as potential candidates for the treatment of polluted water.

A review of physical, chemical and biological synthesis methods of bimetallic nanoparticles and applications in sensing, water treatment, biomedicine, catalysis and hydrogen storage.

This article provides an in-depth analysis of various fabrication methods of bimetallic nanoparticles (BNP), including chemical, biological, and physical techniques. The review explores BNP's diverse uses, from well-known applications such as sensing water treatment and biomedical uses to less-studied areas like breath sensing for diabetes monitoring and hydrogen storage. It cites results from over 1000 researchers worldwide and >300 peer-reviewed articles. Additionally, the article discusses current trends, actionable recommendations, and the importance of synthetic analysis for industry players looking to optimize manufacturing techniques for specific applications. The article also evaluates the pros and cons of various fabrication methods, highlighting the potential of plant extract synthesis for mass production of capped BNPs. However, it warns that this method may not be suitable for certain applications requiring ligand-free surfaces. In contrast, physical methods like laser ablation offer better control and reactivity, especially for applications where ligand-free surfaces are critical. The report underscores the environmental benefits of plant extract synthesis compared to chemical methods that use hazardous chemicals and pose risks to extraction, production, and disposal. The article emphasizes the need for life cycle assessment (LCA) articles in the literature, given the growing volume of research on nanotechnology materials. This article caters to researchers at all stages and applies to various fields applying nanomaterials.

Removal of organic micropollutants from water by adsorption on thermo-plasma expanded graphite encapsulated into calcium alginate.

Nowadays, public concern is focused on the degradation of water quality. For this reason, the development of innovative technologies for water treatment in view of (micro)pollutant removal is important. Indeed, organic (micro)pollutants, such as pharmaceuticals, herbicides, pesticides and plasticizers at concentration levels of µg L-1 or even ng L-1 are hardly removed during conventional wastewater treatment. In view of this, thermo-plasma expanded graphite, a light-weight innovative material in the form of a powder, was encapsulated into calcium alginate to obtain a granular form useful as filtration and adsorption material for removal of different pollutants. The produced material was used to remove atrazine, bisphenol-A, 17-α-ethinylestradiol and carbamazepine (at concentration levels of 125, 250 and 500 µg L-1) by top-down filtration. The effect of flow rate, bed depth and adsorbent composition was evaluated based on breakthrough curves. The experimental data was analysed with the Adams-Bohart model in view of scale-up. Under optimal conditions, removal and adsorption capacity of respectively about 21%, 21%, 38%,42%, 43 µg g-1, 44 µg g-1, 37 µg g-1 and 87 µg g-1 were obtained for atrazine, bisphenol, 17-α ethinylestradiol and carbamazepine when using 0.12 g of thermo-plasma expanded graphite to treat 200 mL at 500 µg L-1 (for each compound) of solution obtaining at contact time of 20 min. The granular form of TPEG obtained (GTPEG) by entrapping in calcium alginate results to have a good adsorbent property for the removal of carbamazepine, atrazine, bisphenol A and 17-α ethinylestradiol from water at concentration levels between 250 and 500 µg L-1. Promising results confirm the adsorbent properties of TPEG and push-up us to investigate on its application and improve of its performance by evaluating different entrapping materials. Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-023-00876-9.

Microbial genome (Illumina MiSeq) sequencing of drinking water treatment residuals to evaluate compatibility with environmental applications.

The clarification of drinking water leads to the production of large quantities of water treatment residuals (WTRs). DNA was extracted from six WTR samples collected from water treatment plants within the UK to compare their bacterial communities and examine whether factors such as coagulant usage (aluminium versus iron salt), the type of water source (reservoir or river), or leachable chemical composition influence these communities. Bacterial 16S variable region 4 (V4) was amplified and sequenced using Illumina MiSeq sequencing. The most abundant phyla in WTR samples were Proteobacteria, Actinobacteria, Bacteroidetes, Acidobacteria, and Firmicutes, collectively representing 92.77-97.8% of the total bacterial sequences. Statistical analysis of microbial profiles indicated that water source played a significant role in microbial community structure, diversity, and richness, however coagulant type did not. PERMANOVA analysis showed that no single chemical variable (pH, organic matter, or extractable element concentration) influenced microbial composition significantly; however, canonical correspondence analysis of WTR microbiomes yielded a model using all these variables that could be used to explain variations in microbial community structures of WTRs (p < 0.05). No common, potentially toxic cyanobacteria, or related pathogens of concern were found. Analysis with PICRUSt showed that WTRs all had similar predicted microbial functional profiles. Overall, the results indicate that WTRs analysed in this study are unlikely to pose any threat to soil microbial community structure when applied to land as a soil conditioner or enhancer and may help to enhance the soil microbial community.

Significance of MOF adsorbents in uranium remediation from water.

Uranium is considered as one of the most perilous radioactive contaminants in the aqueous environment. It has shown detrimental effects on both flora and fauna and because of its toxicities on human beings, therefore its exclusion from the aqueous environment is very essential. The utilization of metal-organic frameworks (MOFs) as an adsorbent for the removal of uranium from the aqueous environment could be a good approach. MOFs possess unique properties like high surface area, high porosity, adjustable pore size, etc. This makes them promising adsorbents for the removal of uranium from contaminated water. In this paper, sources of uranium in the water environment, human health disorders, and application of the different types of MOFs as well as the mechanisms of uranium removal have been discussed meticulously.

Enhanced antibacterial properties and magnetic removal of Fe3O4/fenugreek seed gum/silver nanocomposites for water treatment.

This study reports the synthesis, characterization, and antibacterial activity of a novel Fe3O4 nanocomposite coated with fenugreek seed gums and silver nanoparticles (AgNPs). To enhance the antibacterial properties of AgNPs and overcome the limitations of conventional methods for the production of three-component nanocomposites, a layer of natural polymer was used. Fenugreek seed gums (FSG) were used to coat Fe3O4 NPs to prevent their decomposition and to facilitate the release of silver nanoparticles in aqueous media. The Fe3O4/FSG/Ag nanocomposites were characterized and then the antibacterial activity of the nanocomposites was evaluated against two gram-negative and two gram-positive bacteria and compared with Fe3O4, Fe3O4/FSG, FSG, and AgNO3. The results showed that the Fe3O4/FSG/Ag nanocomposites had higher antibacterial activity than the other samples and could be easily removed from treated water by a powerful magnet without causing pollution in the environment. Overall, these findings suggest that the Fe3O4/FSG/Ag nanocomposites have potential applications in water treatment for their improved antibacterial properties and ease of removal.

A circular economy approach to drinking water treatment residue management in a catchment impacted by historic metal mines.

Drinking water treatment residues (DWTR) from mining areas which remove and contain potentially toxic elements (PTE) could still potentially be used as a soil amendment to restore contaminated sites in the same catchment, thus eliminating waste and reducing the chemical and physical mobility of the pollutants. To assess this restorative and regenerative approach to DWTR management, field and pot trials were established with soils from a historic Pb-Zn mine site in the North East of England, amended with either local DWTR or the nearest available municipal green waste compost (GWC). Soils from the mine site were found to have very low levels of nutrients and very high levels of PTE (Pb and Zn > 13, 000 mg/kg). The perennial grass species Phalaris arundinacea, known for many ecosystem service benefits including soil stabilization, was used throughout this study. The application of the BCR sequential extraction to soils amended with the DWTR in the pot trials found a significant decrease in the bioavailability of Pb and Cu (p < 0.05) after plant growth when compared with an unamended control. The field trial involved 648 pre-grown grass plants planted-out into mine soils amended with either DWTR, GWC or a mixture (MIX) of the two, all at rates of 25-30% w/w. Both amendments and the MIX had significant positive effects on biomass production compared to the unamended control in the following order GWC > MIX > DWTR (p < 0.05). Results of the elemental analysis of biomass from the field trial were generally ambiguous and did not reflect the decreased bioavailability noted in the pot trials using the BCR procedure. Pot trials, however, showed increases in plant growth and decreases in concentrations of Cr, Cu, Pb and Zn in above ground biomass following the application of both amendments. Further work should involve the testing of a mixture of DWTR and other soil amendments to enhance plant growth. The success of these trials should provide confidence for those working in drinking water treatment and catchment management to reuse the waste residues in a circular economy and a sustainable way that could improve water quality over time.

Sediment resuspension causes horizontal variations in the distributions of phosphorus (P) and P-inactivating materials with differing P immobilization in different sediment planes.

The importance of controlling internal phosphorus (P) pollution in lakes has been recognized by scientists, and the application of P-inactivating materials to immobilize sediment P is often considered. However, sediment resuspension, a typical physical process occurring in lakes, has been demonstrated to increase the uncertainty of immobilization. In this study, we explored the characteristics of P immobilization in the horizontal direction under the effects of resuspension using annular flume tests based on drinking water treatment residuals (DWTR). The results showed that resuspension caused the mobile P and bioavailable P to be heterogeneously distributed in sediment planes after DWTR addition, resulting in varying P immobilization efficiencies at different depths. In particular, the coefficient of variation was 14.2-24.5% for mobile P horizontally distributed in the planes, resulting in a range of mobile P decreasing efficiencies at 24.0-47.8%. Further analysis indicated that variations in horizontal distribution were typically due to the varied migration of particles of different sizes. Specifically, P immobilization in sediment planes at different depths was regulated by promoting the migration of <8 µm DWTR after relatively low-intensity disturbance (in surface 0-1 cm sediment). After relatively high-intensity disturbance (in the whole 0-3 cm sediment), immobilization in the horizontal direction was regulated by coupling the migration of >63 µm DWTR (to the bottom) with the mixing of <8 µm DWTR in the sediment plane at different depths. The varying horizontal distributions of total P, resulting from the migration of 16-32 µm sediment, could enhance the heterogeneities of the P immobilization. Thus, the particle size of materials and lake background conditions, for example, the hydrodynamic characteristics and P distributions in differently sized sediments, should be used as key bases to select or develop P-inactivating materials to design proper remediation strategies for controlling internal P pollution in lakes.

Improvement of the optical, photocatalytic and antibacterial properties of ZnO semiconductor nanoparticles using different pepper aqueous extracts.

Peppers are fruits that grow on plants of the genus Capsicum and are popular for their use in gastronomy as a condiment and for their anti-inflammatory and anti-cancer properties due to their phytocompounds such as flavonoids, polyphenols, or alkaloids. Semiconductor zinc oxide (ZnO) nanoparticles (NPs) were synthesized using a green approach employing natural aqueous extracts of several varieties of peppers (jalapeño, morita, and ghost). The obtained NPs were characterized by different techniques, and their photocatalytic and antibacterial activity was studied. The signal at 620 cm-1 in the FTIR spectra belonging to the Zn-O bond, the appearance of the main peaks of a hexagonal wurtzite structure in the XRD pattern, and the characteristic signals in the UV-Vis spectra confirm the correct formation of ZnO NPs. The photocatalytic activity was analyzed against Methylene Blue (MB), Rhodamine B (RB), and Methyl Orange (MO) under UV and sunlight. All syntheses were able to degrade more than 93% of the pollutants under UV light. Antibacterial assays were performed against gram-positive and gram-negative bacteria. All syntheses exhibited antibacterial activity against all bacteria and maximum growth inhibition against Bacillus subtilis. The prominent results demonstrate that natural aqueous extracts obtained from peppers can be used to synthesize ZnO NPs with photocatalytic and biomedical applications.

Phosphorus adsorption and organic release from dried and thermally treated water treatment sludge.

The study investigated water treatment sludge (WTS) as a phosphorus (P) adsorbent and examined the release of organic matter during the P adsorption process. Previous studies indicated that WTS is an effective adsorbent for P but also releases organic matter, which may affect the organoleptic properties of treated water, but no study has characterised organic release and conducted an in-depth study on its behaviours. This study characterised the organic release during the P adsorption process from four different WTS samples. This study also offers results from a 60-day column experiment that indicate that WTS columns effectively removed the majority of P from the 2 mg/L feed solution. The total organic carbon (TOC) release was gradually reduced from 24.9 mg/L on day 1 to stable levels of 4.4 mg/L to 4.1 mg/L from day 22 onwards. After 60 days, when the organic matter was nearly exhausted, WTS columns were still effective in P adsorption from the solution. In addition, the thermal treatment of WTS at different temperatures was investigated to reduce TOC release and increase P adsorption. The results showed that thermal treatment not only minimized TOC release but also enhanced the P adsorption capacity of the sludge. In a 24-h batch experiment, WTS treated at 600 °C showed the highest P adsorption (1.7 mg/g) with negligible TOC release when compared to sludge treated at 500 °C WTS (1.2 mg/g), 700 °C WTS (1.5 mg/g) and dried WTS (0.75 mg/g). However, the release of inorganic compounds slightly increased after thermal treatment. Future studies could focus on determining whether the thermal processing of WTS which can enhance the WTS's adsorption to emerging pollutants like per- and poly-fluoroalkyl substances and other contaminants. The findings of this study could influence the management practices of water authorities and contribute to the water sector's sustainability objectives.