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Colloidal solutions of gold nanorods and silver-coated gold nanorods were prepared. The seeded growth synthesis protocols were improved by adding a flocculation purification step. The resulting populations of pure gold nanorods and Au@Ag core–shell cuboids were characterized by very low dispersion in size and shape. UV–vis–near-infrared absorption measurements were performed on several batches of well-calibrated nano-objects, supported by calculations based on the discrete dipole approximation, allowed to highlight the impact of various morphological features on the optical response. In addition to the well-known effect of the nanorod aspect ratio on the shift of the longitudinal surface plasmon resonance mode, special attention was paid to changing either the rounding of the nanorod end-caps or that of the edges of the coating silver shell. Nanorods and cuboids were modeled as superellipsoids. This approach enabled us to model precisely their complex shapes using just a few simple parameters and analyze the evolution of their extinction spectra as a function of the rounding of their tips and edges. Such nano-objects are widely used for various applications in fields such as biomedical, biosensing, or surface-enhanced Raman spectroscopy, thus making it crucial to precisely assess the impact of each morphological feature for optimizing their performance. [ABSTRACT FROM AUTHOR]

In this study, Bi2O3/TiO2 composite was successfully synthesised using the solvothermal method, and the morphology, composition, and surface area of the composite were determined. Comparisons of photocatalytic performance were performed using Bi2O3/TiO2 for the decomposition of Atenolol (ATN) a β-blockers that is generally used to treat disorders such as hypertension and arrhythmias, as a model contaminant under visible light irradiation. The effects of different parameters such as solution pH, catalyst dosage, initial ATN concentration, reaction time, coexisting cations and anions, and turbidity on the degradation efficiency of ATN were investigated. An excellent synergistic effect was observed in the decomposition of ATN with the simultaneous application of Bi2O3/TiO2 and LED compared to single processes (synergistic index value, 4.027). The Bi2O3 catalyst has a much lower photocatalytic performance for the decomposition of ATN than the synthesised Bi2O3/TiO2 composite. The optimal rate for pH, catalyst dosage, and initial concentration of ATN was 7, 400 mg/l and 10 mg/l, respectively. Under optimal conditions, about 68.92% and 22.58% of ATN were degraded after 60 minutes in the presence of Bi2O3/TiO2 and Bi2O3 catalysts, respectively. However, these efficiencies are reduced to 51.83% and 12.4%, respectively, under 50 NTU. The addition of co-existing anions, especially PO43⁻, remarkably reduced the efficiency of ATN removal in the Bi2O3/TiO2/LED process. The presence of cations promoted the degradation of ATN in the Bi2O3/LED process, while the efficiency of ATN degradation was inhibited by the presence of cations in the Bi2O3/TiO2/LED process. The ATN removal efficiency using LED irradiation (49.02%) was much higher than that of UV-C irradiation (27.16%) when the concentration of ATN was 30 mg/L. [ABSTRACT FROM AUTHOR]

Current review reports coagulation-based flocculation for treatment of radioactive wastewater. At low pH, high dosages are necessary to achieve charge neutralization resulting poor separation yield. Most radionuclides coagulate and flocculate under alkaline conditions. Stirring also affects the morphology of flocs while excessive stirring re-dissolves the flocs and decreases the SEPARATION yield. Yield depends on coagulant mixing rate, pH, concentration, temperature, stirring time and rate, settling time and sedimentation rate. The commonly used coagulants are Fe and Al while Fe is famous among all coagulants. This review is useful to develop a radionuclides separation plan from environmental protection perspective in the emergency situation. [ABSTRACT FROM AUTHOR]

Recently, researchers are racing to introduce novel, natural, and non-toxic coagulants for effective wastewater treatment without adversely impacting the environment. Extensive research on the utilization of natural compounds for wastewater treatment has garnered attention due to the toxic reaction of the chemical-based water treatment agents and their by-products. Plant seed extracts, chitosan, alginate, starch, tannins, cactus mucilage, and agricultural wastes are some of the natural compounds that have been identified for effective wastewater treatment. Although these natural compounds are beneficial in wastewater treatment, their stability in aqueous mediums remain a major concern to be utilized for large-scale water treatment plants. Among these natural compounds, starch-derived coagulants are gaining recognition in the field of water treatment due to presence of unique functional groups, such as carboxyl and hydroxyl groups that are attached to their polysaccharide ring, post effective modification. Hence, this review provides an overview of recent progress of natural coagulants in the field of flocculation and coagulation studies. It also discusses modification techniques applied to various types of starch that have been identified to be effective in the treatment of both turbid water and their potential as an effective disinfectant. • Valorization of agriculture waste into cationic starches promote sustainability. • Distinct process conditions affecting coagulation –flocculation is discussed. • Physical and chemical modification methods of starch with pros and cons is reviewed. • Cationic starch is a good substitute to chemical coagulant with varied applications. • The advancements of cationic starches in water treatment industry is highlighted. [ABSTRACT FROM AUTHOR]

Vacuum preloading combined with flocculation has shown great potential for improving the dredged sludge's dewatering and consolidation. To identify a suitable flocculant combined with vacuum preloading method, this study investigated the effects of various common flocculants on the sludge's filtration properties and consolidation behaviors. The results indicated that dual-use of polymeric aluminium chloride (PAC) and polyacrylamide (PAM) had the most significant improvement on sludge's filtration performance, as reflected by capillary suction time. In addition, a single dose of PAM had the most substantial improvement on the sludge's compressibility. While, lime improved the sludge's permeability the most. To predict the consolidation settlement of flocculated sludge during vacuum preloading, a method was proposed based on a small homemade vacuum preloading apparatus and the Taylor method. The influence of different flocculants on sludge properties was also analyzed based on their flocculation mechanisms and microstructure. Finally, an appropriate flocculant for the sludge in vacuum preloading projects was suggested in accordance with different project goals. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the use of commercial tannin derivatives, namely, tannin 1 (CT1), tannin 2 (CT2), tannin 3 (CT3), and extract of tannin produced from angico bark, as aggregation agent in hematite–silica systems. Hematite and quartz were used in aggregation tests at dosages of 1, 10, and 100 mg/L at pH values of 6–9. The zeta potential and Jar tests were conducted in the best conditions of aggregation tests. The condensed tannin content of the commercial reagents is approximately similar, and it exceeds the content found in the extract obtained from angico bark. CT3 demonstrated superior percentages of sedimented material for both minerals at a dosage of 10 mg/L and pH 7 (97.12% and 95.68% for hematite and quartz, respectively). The aggregation agent produced from the angico bark displayed good sedimentation results for hematite (>90%); however, the results for quartz were unsatisfactory. The isoelectric point shifts to pH 8 when each mineral was conditioned with CT3. The jar test revealed higher sedimentation of the compositions for the lowest velocity gradient (60 rpm) with low turbidity values in the supernatant; however, the lowest turbidity (24.71 NTU) is observed in the sample with a higher percentage of hematite. [ABSTRACT FROM AUTHOR]

Highly turbid industrial effluent poses significant challenges to environmental sustainability. In this study, we investigated the optimal aggregation kinetics for the removal of colloidal and turbid particles in Cosmetics and Personal Care Products (CPCP) industrial effluent using calcined eggshell (CES) and industrial-grade aluminum sulfate as flocculants. The effluent characteristics were determined following ASTM specifications, and process optimization was carried out using a response surface design approach. The optimal operating conditions at a settling time of 3 min were found to be pH 8, 0.2 g/L dosage of CES, pH 10, and 0.3 g/L of alum dosage. The flocculation efficiencies of CES and alum were found to be 80% and 78%, respectively, demonstrating the effectiveness of both flocculants in removing colloidal particles and reducing turbidity in CPCP effluent. Mechanistic studies revealed that CES achieved particle removal through enmeshment and inter-particle bridging with a significant aggregation rate (1.3 × 10−7) and a lower floc breakup tendency (2.8 × 10−14) compared to alum-sweep flocculation. The hydrodynamics at a velocity gradient of 269s−1 ≤ G ≤ 29s−1 indicated spontaneous agglomeration within a flocculation period of ≤10 min, indicating rapid and efficient particle removal. The findings of this study justify the use of CES as a sustainable and effective option for the removal of colloid/turbid particles from CPCP effluent. The optimized operating conditions and mechanistic insights into the flocculation process contribute to establishing an optimized sedimentation geometry, with specified aspect ratio, detention time, hypothetical settling, and sludge depth for CES, ensuring the favorable stability of the finished CPCP effluent before discharge. [ABSTRACT FROM AUTHOR]

The response of suspended tenuous clay-polysaccharide flocs to hydrodynamic shearing was investigated in the laboratory via particle size analyses to understand the molecular-scale interactions between clay minerals and polysaccharides and their hydrodynamic behavior such as size kinetics, re-flocculation/breakdown, and shear strengths of the hybrid flocs. While the studied suspensions had a fixed clay concentration of 0.4 g/L, an array of other parameters was varied to reflect the complexity of clay-polysaccharide systems, including four types of clay minerals with varying layer charges and swellability (i.e., kaolinite, illite, and sodium- (Na-) and calcium- (Ca-) montmorillonites), two exopolymers of dissimilar polarities (i.e., xanthan and guar), six polysaccharide (P) to clay (C) weight ratios (i.e., P / C = 0, 1, 2, 5, 10, and 20 wt%), and three hydrodynamic shearing rates of 187, 429, and 1,100 1/s (i.e., corresponding to laminar, transitional, and turbulent flows, respectively). Results show that the clay-polysaccharide floc sizes are sensitive to the shear stress and also vary with different clay-polysaccharide systems. Four discrete particle groups were identified by statistical analyses, consisting of primary particle (PP), flocculi (FL), microfloc (MiF), and macrofloc (MaF), which exhibit distinct stabilities to shearing. The MaF is much weaker than MiF and can easily breakdown, as indicated by the decrease in MaF fraction with increasing shearing, while the MiF is the dominant particle group in transitional and turbulent flows. The fractions of PP and FL generally increase with shearing rate. Based on floc survivability in different flow conditions, the MaF's upper and lower bound shear strengths were estimated to be 0.95 and 0.17 Pa, respectively. The strongest MaF with a maximum shear strength of 0.95 Pa is formed in the clay-guar suspensions at a P / C of 10 wt%. Anionic xanthan only forms flocs with kaolinite with little surface charges, but cannot induce clay-polysaccharide flocs for illite and Ca/Na-montmorillonite with negative surface charges due to electrostatic repulsion. In contrast, neutral guar generates flocs with all 4 clay minerals due to the formation of hydrogen bonds, and MaF compounds usually are absent in turbulent flow (except kaolinite with a small fraction of MaF). These results further demonstrate the essential role of polysaccharide's polarity in dictating the flocculation dynamics, and, hence, sediment transport behavior. Practical implications of the findings are discussed in terms of the emerging technological applications of clay-polymer systems as well as the transport and modeling of natural aquatic cohesive sediment in biofilm-bearing waters. • Clay-polysaccharide floc sizes vary with clay mineral and biopolymer polarity. • Clay-polysaccharide interaction and flocculation are affected by flow shear stress. • The clay-biopolymer suspensions exhibit multimodal particle size distributions. • Floc strengths are compared and estimated based on floc survivability. [ABSTRACT FROM AUTHOR]

Rising concerns over water pollution and the depletion of non‐renewable resources have propelled the exploration of eco‐friendly and sustainable wastewater treatment alternatives. Biopolymer‐derived graft copolymers emerge as a promising solution, offering biodegradability, cost‐effectiveness, versatility, and enhanced functionality. This review provides a comprehensive overview of the latest developments in utilizing these copolymers as eco‐friendly flocculants for wastewater treatment. It covers synthesis methods for functionalized biopolymer‐based flocculants, diverse flocculation mechanisms, and their efficacy in solid–liquid separation. The article explores applications for removing pollutants, emphasizing biodegradability, cost‐effectiveness, and versatility. Special attention is given to the environmental impact, critically analyzing how these copolymers contribute to sustainable water treatment practices. The review also discusses potential future prospects and advancements in addressing global water pollution challenges using biopolymer‐derived graft copolymers. [ABSTRACT FROM AUTHOR]

Over these last years, there is no doubt that the conventional chemical flocculants commonly used for wastewater treatment have been a source of serious human health threats and environmental damage. Consequently, safe and eco-friendly substitutes are worth looking for and assessing. Within this line, flocculants derived from cactus namely, cladodes juice (CJ), powders of lyophilized (CLP) and oven-dried (CDP) cladodes, were developed as alternatives to the noxious synthetic ones. The flocculating activity of these three extracts was evaluated in treating a synthetic Disperse Blue-1 (DB-1) dye solution and a real industrial effluent loaded with heavy metals. A prominent DB-1 removal of up to 80% was achieved using CJ, CLP and CDP. Significant colour and turbidity reductions (94%) were attained using only 20 mg/L of CLP. Likewise, the cactus bio-flocculants complementing alum as a coagulant ensured an enhanced Zn removal from the industrial wastewater. For instance, both CLP and CDP allowed salient Zn uptake exceeding 99% against 69% using the CJ formula. The slight disparity in the flocculating activity between these three formulations could be ascribed to their preparation procedures affecting the integrity of their active agents (polysaccharides and chiefly polygalacturonic acid). Further, it is thought that the presence of hydroxyl (–OH) and carboxyl (–COOH) groups on this latter's backbone confers the cactus extracts a notable flocculating ability regardless of the type of water pollutants. The plausible flocculation mechanisms for DB-1 molecules and Zn removal are assumed to be adsorption-bridging and adsorption-charge neutralization, respectively. [ABSTRACT FROM AUTHOR]

Chemically enhanced primary treatment (CEPT) is a rapid wastewater treatment process involving treating wastewater with two chemical-aided processes, coagulation, and flocculation. In the present study, a natural extracellular polymeric substance flocculant (EPSBF) produced by Klebsiella pneumonia UKD24, a bacterium isolated from the sewage treatment plant, and a synthetic polyacrylamide anionic polymer flocculant (PAM) were evaluated to treat polluted river water. The synthetic PAM showed immediate turbidity reduction after agitation, while the EPSBF expressed a rapid decrease in optical density. After 20 min of the settling period, the EPSBF showed reduced rates of turbidity, optical density, and chemical oxygen demand at 74.14 ± 5.2%, 89.37 ± 0.76%, and 87.21 ± 0.73%, respectively, while PAM showed 67.08 ± 4%, 85.68 ± 2%, and 86.57 ± 2%, respectively. EPSBF treatment significantly improved the water quality parameters in terms of total dissolved solids, total suspended solids, conductivity, and oxidation–reduction potential than PAM treatment. However, the EPSBF has shown a more water-holding capacity and relatively weak flock formation, producing more sludge volume than PAM. Furthermore, though the sludge produced by the EPSBF treatment had a higher moisture content, it showed shorter capillary suction time (CST). In contrast, sludge formed in PAM treatment had lower moisture content, but it exhibited prolonged CST value indicating that PAM treatment sludge showed slow dewaterability. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Alkaline‐extracted walnut protein isolates (WPI) exhibit limited solubility, which poses challenges for their application in the food industry. The present study investigated the effects of protein‐glutaminase (PG) deamidation on the physicochemical characteristics, solubility and emulsifying properties of WPI.The deamidation process of WPI was monitored by assessing the release of free ammonia and the reduction in solution turbidity. PG deamidation significantly increased the surface charge of WPI and modified its surface hydrophobicity with increasing deamidation degree (DD), resulting in a gradual improvement in solubility by approximately 50–70%. Furthermore, the emulsifying capacity of deamidated WPI (DeWPI), specifically at 0.25 h (DeWPI0.25, DD 7%) and 9 h (DeWPI9, DD 23%), was evaluated for stabilizing low internal phase emulsions (LIPEs) and high internal phase emulsions (HIPEs). LIPEs stabilized by WPI and DeWPI0.25 exhibited significant flocculation of oil droplets, leading to decreased stability against heat, salt treatment and storage compared to those stabilized by DeWPI9. DeWPI‐stabilized HIPEs showed a 2–2.5‐fold higher storage modulus compared to those stabilized by WPI. However, HIPEs stabilized by DeWPI0.25 displayed higher flow stress and flow strain compared to DeWPI9‐stabilized HIPEs. Overall, DeWPI‐stabilized HIPEs demonstrated relatively high physical stability against storage, heat treatment and high ionic strength.PG deamidation significantly enhanced the solubility and influenced the emulsifying properties of WPI in a manner dependent on the DD. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this paper, we study a system of reaction–diffusion equations arising from the competition of two competing species for a single limited nutrient with flocculation in an unstirred chemostat. By the conservation principle, we reduce the dimension of the system by eliminating the equation for the nutrient. Then the global structure of the reduced system is studied by the bifurcation theory in its feasible domain. Finally, we use numerical simulation to verify and supplement our theoretical results. [ABSTRACT FROM AUTHOR]

Whey is the largest waste product of the cheese-making industry and the current methods of extracting the nutrients from it are costly and inefficient. This study assessed the feasibility of using crude polysaccharides to flocculate proteins from liquid whey waste. The flocculants used were a sugar kelp (Saccharina latissima) extract, as well as commercial seaweed polysaccharides, alginate and k-carrageenan, to recover proteins from the liquid whey waste. Physicochemical and functional parameters including protein content, protein recovery efficiency, mineral content, total phenolic content (TPC), antioxidant capacity, color, water- and oil-holding capacity, gelling capacity, foaming activity and stability, and emulsifying activity and stability were tested on the resulting flocculates. The yield of the dried flocculates by use of alginate, the sugar kelp polysaccharide extract (SKPE), and carrageenan were 1.66, 0.98, and 1.22 g/100 g of liquid whey with protein contents of 27.4%, 45.5%, and 37.5%, respectively. The protein recovery efficiency from the whey was 57.5%, 56.2%, and 57.9% using alginate, SKPE, and carrageenan, respectively. The alginate flocculate had the highest oil-holding capacity and foaming abilities while the carrageenan flocculate had the best gelling ability and the highest emulsifying activity and stability. TPC and antioxidant activity were highest in the SKPE flocculate. All three flocculates presented slightly different compositional and functional qualities, which could be used for a variety of products. This study showed that seaweed polysaccharides present a simple and effective way to extract protein from liquid whey waste while creating a functional and high-protein ingredient. [ABSTRACT FROM AUTHOR]

Research has consistently prioritized the study of biopolymers generated from microbes because of their inherent ability to decompose naturally. This work utilized peanut hull and wheat bran extract as a fermentation medium, under statistically optimal circumstances, to manufacture a bioflocculant. The bioflocculant, developed from a multiple consortium, was aimed at enhancing the yield for commercial purposes. The self assembled bioflocculant (Sa@bio) is a unique compound that can develop an asymmetric structure, making it highly valuable for various applications. Sa@bio consists of raffinose, mannose, and glucose, all of which possess a notably negative charge. Analysis conducted by Sa@bio indicated that the percentages of oxygen, carbon, phosphorus, potassium, and nitrogen were 23.72%, 68.03%, 2.73%, 1.33%, and 4.19% correspondingly. In addition, Sa@bio can serve as a reducing and stabilizing agent for the synthesis of nanoparticles, specifically gold nanoparticles (NPs-AuNPs) and silver nanoparticles (AgNPs) known as (Sabio@MNps) Self assembled bioflocculant capped metal nanoparticle. Sabio@MNps and Sa@bio were analyzed using UV–Vis spectroscopy, XRD, FTIR, FESEM, and HRTEM to determine their structural properties. The sorbents Sa@bio and Sabio@MNps shown superior biosorption capabilities for Cu2+ > Zn2+ > Hg2+ > Cd2+ compared to other sorbents. Moreover, the versatile capabilities of Sa@bio, Sabio@MNps shown can be regarded as suitable for pharmacological, bio therapeutic and entomological uses. This study presents the initial findings in the development of a cost-effective, environmentally friendly, non-toxic, and stable biopolymer utilizing readily available ingredients. [ABSTRACT FROM AUTHOR]

This study examines the geotechnical and hydro-mechanical behaviour of a model slurry used in high-solids, high-salinity applications, both before and after inline flocculation with an anionic polyacrylamide. Initial evaluations showed untreated tailings (UT) with a water content of 107%, void ratio of 2.6, and dry density of 0.711 t/m3, compared to polymer-amended tailings (PAT) with 53% water content, a void ratio of 1.6, and a dry density of 1.069 t/m3. Post-flocculation consolidometer tests revealed a distinct consolidation mode, with PAT showing 60% less settlement within the first 48 h and achieving 50% more free water drainage. Polymer treatment improved consolidation parameters, yielding a lower compressibility index (Cc of 0.74 vs. 1.05 for raw slurry), a higher coefficient of consolidation (Cv of 0.005 cm2/s for PAT vs. 0.0009 cm2/s for raw slurry), and an increased water retention capacity. Additionally, PAT demonstrated a final void ratio of 0.62 compared to 0.51 for the UT sample and an internal porosity characterised by discrete voids, supporting enhanced stability for long-term rehabilitation. These findings underscore the potential of inline flocculation to improve tailings management in saline conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Future applications of high‐internal‐phase emulsions (HIPEs) are highly regarded, but poor freeze–thaw stability limits their utilization in frozen products. This study aimed to characterize the structure of chickpea protein microgel particles (HCPI) induced by NaCl and to assess its impact on the freeze–thaw stability of HIPEs. RESULTS: The results showed that NaCl induction (0–400 mmol L−1) increased the surface hydrophobicity (175.9–278.9) and interfacial adsorbed protein content (84.9%–91.3%) of HCPI. HIPEs prepared with HCPI induced by high concentration of NaCl exhibited superior flocculation index and centrifugal stability, and their freeze–thaw stability was better than that of natural chickpea protein. The increase in NaCl concentration reduced the droplet aggregation and coalescence index of the freeze–thaw emulsions, diminishing the precipitation of oil from the emulsion. Linear and nonlinear rheology showed that the strengthened gel structure (higher G′ values) restricted water flow and counteracted the damage to the interfacial film by ice crystals at 100–400 mmol L−1 NaCl, thus improving the viscoelasticity of the freeze–thaw emulsions. Finally, the thawing loss of surimi gel with HCPI‐200 HIPE was reduced by 2.04% compared to directly adding oil. CONCLUSION: This study provided a promising strategy to improve the freeze–thaw stability of HIPEs and reduce the thawing loss of frozen products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to determine the effect of bittern coagulant dosage and rapid stirring speed on reducing the concentrations of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and dye absorbance in batik industry wastewater, as well as to identify the optimum coagulant dosage and stirring speed. Wastewater samples were collected from a batik industry in the batik center of Sidoarjo, East Java, Indonesia. Dosage variations of 5%, 10%, 15%, and 20% were tested alongside rapid stirring speeds of 100 rpm, 130 rpm, and 160 rpm. The study was conducted on a laboratory scale using the jar test method. Initial wastewater characteristics showed BOD, COD, TSS, and dye absorbance concentrations of 185.68 ± 29.34 mg/L, 10.091 ± 363.24 mg/L, 2.231.33 ± 155.55 mg/L, and 0.212 ± 0.02, respectively. Statistical analysis using the Pearson correlation test and Two-Way ANOVA revealed that variations in coagulant dosage and stirring speed significantly impacted the reduction percentages of BOD, COD, TSS, and dye absorbance. The optimal coagulant dosage was found to be 5%, and the optimal stirring speed was 100 rpm, with reduction percentages for BOD, COD, TSS, and dye absorbance being 80.32%, 65.86%, 92.35%, and 70.77%, respectively. [ABSTRACT FROM AUTHOR]

Although adding flocculants is an essential step in wastewater treatment and maintaining the stability of the solid-state in solution to produce a loose cell-like structure, in some instances, polymeric material fails to support this due to specific surface charges. Therefore, the current study aimed to develop a cationic form (CBS) obtained from unripe waste bananas as native starch and characterize it as a flocculating agent. The starch from unripe waste banana fruit peel was extracted and synthesized to CBS using an etherification reaction via grafting a cationic moiety such as 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC). In addition, the synthesis process was optimized using quality by design (QBD). The utilization of QBD led to the attainment of the maximum degree of substitution (DS) value of 0.623 under optimal circumstances, which involved reacting moieties such as CHPTAC (0.007 moL) and NaOH (30% w/v) with a reaction duration of 18 h at a temperature of 50 °C. Moreover, elemental, structural, x-ray diffraction, thermal analysis, and surface morphology indicated that a significant cationic fraction was integrated within the BS. In addition, the biocompatibility study showed that both native BS and CBS were > 95% biocompatible against CaCO-2 and HeK-293 cells. Furthermore, the flocculation performance of CBS showed that the transmittance of the supernatant fluid augmented in direct correlation to the sedimentation and flocculation time for CBS. Thus, the modified CBS can be utilized as an economical, safe, and potential substitute against available flocculating agents. [ABSTRACT FROM AUTHOR]

BACKGROUND: Arsenic contamination can exert severe detrimental effects on the ecological environment and human health. It can cause acute or chronic poisoning, resulting in cell distortion or cancer when humans come into contact with or consume arsenic‐containing water. Adsorption technology is one of the effective methods for arsenic removal. In this study, using attapulgite (ATP) as a support for bimetallic iron–manganese oxides, a series of adsorbents (Fe‐Mn/ATP) with different manganese‐to‐iron molar ratios were prepared via the coprecipitation method. Scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy mapping, X‐ray diffraction and zeta potential measurements were used to analyze the structure and properties of Fe‐Mn/ATP. In addition, the adsorption performance of the material for arsenic ions was investigated by static adsorption and dynamic adsorption experiments. RESULTS: A novel Fe‐Mn/ATP adsorbent was prepared using ATP as the raw material and manganese‐to‐iron molar ratio was 1:3 by coprecipitation at 60 °C for 1 h. The adsorption efficiency of arsenic ions was optimal at an Fe‐Mn/ATP dosage of 2 g L−1, pH 4 and a contact time of 10 min, reaching a maximum adsorption capacity of 38.27 mg g−1 at room temperature. The adsorption process followed the pseudo‐second‐order kinetic model and the Langmuir isotherm adsorption model, indicating that arsenic ion adsorption by Fe‐Mn/ATP was mainly monolayer chemical adsorption. Furthermore, Fe‐Mn/ATP showed a removal rate for arsenic ions of over 80% after four cycles of regeneration, revealing a great potential for practical application. CONCLUSION: This study offers a promising Fe‐Mn/ATP adsorbent for removal of arsenic ions from wastewater. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Highlights With the rapid development of modern transportation systems, optimizing the relationship between structure and performance to obtain natural rubber‐based nanocomposites with excellent comprehensive performance is still worth to investigation. Herein, the regulation of flocculation potential through different flocculants selection on the thermomechanical properties for carbon black/graphene oxide reinforced natural rubber (CB/GO/NR) nanocomposites were investigated based on the compression electric double layer theory. The results showed that formic acid owned the highest zeta potential with comparison of sodium chloride (NaCl), calcium chloride (CaCl2), and aluminum chloride (AlCl3). Meanwhile, as the content was 8 wt%, tensile strength, tearing strength and thermal conductivity could achieve to 27.64 MPa, 56.89 N/mm, and 1.05 W m−1 K−1, respectively. While the heat generation after compression fatigue dropped to 10.1°C. These findings reveal that the highest zeta potential of formic acid could promote the improvement of flocculation degree between GO and NR latex and significantly enhanced the thermomechanical properties of CB/GO/NR nanocomposites due to the larger flocculation potential difference. Therefore, this study not only provides important theoretical insights for preparing high‐performance NR‐based nanocomposites, but also highlights the crucial role of high zeta potential flocculants in optimizing the composite performance. More importantly, the findings offer the creative insights for preparation of the excellent comprehensive NR nanocomposites for the practical industry application. The effect of flocculation degree on the properties of CB/GO/NR composites was studied. Formic acid was benefit to the flocculation and could promote the surface interaction. CB/GO/NR composites possessed the improved thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

AbstractBased on fractal theory, the geometric size, surface morphology, and spatial structure of flocs in the hydrophobic flocculation process of coal particles were examined via particle size distribution detection, image analysis technology, and numerical simulation. The floc size distribution curve was classified and discussed via the dual-domain fractal rule, and the variation law of the composition and distribution of the coarse- and fine-grained coal particle flocs with the flocculation process was clarified. The various levels and characteristics of the floc growth geometry were explained by the analysis of the fractal dimension of the individual floc surface and the multiple spectra of the floc groups in the metallographic microscopy image. The hydrophobic flocculation process of coal particles was simulated via the diffusion-limited cluster aggregation model. The gyration fractal dimension was used to examine floc fragmentation and reconstruction and clarify the growth law of the floc spatial structure during the hydrophobic flocculation process. [ABSTRACT FROM AUTHOR]

The use of high-strength concrete in construction is expected to increase, and the manufacturing technology employed to produce such concrete needs to adapt to this rise. High-strength concrete has a workability that can vary significantly depending on the mixing conditions, even with the same mix design and in the same environment. This research focuses on the change in workability due to dry-mixing (i.e., mixing of fine aggregate with cement in the early stage) in the mixing process of a high-strength concrete mix using a revolving-double paddle mixer. As a result, it was confirmed that the slump flow value difference caused by dry-mixing was about 25 cm. Furthermore, Cryo-SEM (which can observe the specimens in the frozen state) image analysis revealed that dry-mixing causes flocculation of cement particles. The amount of admixtures adsorbed was then analyzed. This study concluded that flocculation affects the degree and timing of admixture adsorption in the later stages of the mixing process, leading to differences in concrete workability. [ABSTRACT FROM AUTHOR]

Sludge thickening is a fundamental stage of treatment. This study investigated the application, in continuous treatment, of polymeric bubbles produced with cationic polymer P2900 and cocamidopropyl betaine (CAPB), a zwitterionic surfactant. The proposed reagent combination aims to form aerated flakes, solid waste structures, and rapidly rising air bubbles, ideal for treatments in compact units. Using this combination, it was possible to achieve a total solids concentration of 45% with the modified bubbles and 25% with the conventional water treatment. This level of thickening occurred under the following operating conditions: initial total solids (TS) concentration of 10 g L−1, a flow rate of 5 L min−1, saturation pressure (psat) of 3 atm, and polymer dosage of 10 mg (gTS)−1. The suggested mechanism of action involves the adhesion of P2900 molecules to CAPB at the air/water interface, forming a lining on the bubble surface. Additionally, polymerized species form due to the residual aluminum (Al) in the sludge, which would occur during flocculation in the helical tubular flocculator (HTF), adsorbing the micelles and bubbles of CAPB. The critical micellar concentration (CMC) of CAPB was 0.26 mmol L−1. Polymeric bubble technology can provide an efficient and cost-effective approach to sludge thickening in continuous treatment. [ABSTRACT FROM AUTHOR]

The total volume of fluid fine tailings (FFT), reached 1,270 Mm3 in 2019. Extensive research is underway by a number of operators to develop dewatering technologies for oil sand tailings reclamation to comply with Directive 085 issued by the Alberta Energy Regulator. A promising technology for the disposal of FFT is to add flocculents and then use thickeners or centrifuges to decrease the water content. Following this treatment, freezing/thawing processes can then be utilized to further dewater the tailings. The effect of flocculation/flyash addition and thickening coupled with freezing/thawing treatments on FFT was investigated by performing large-strain consolidation and shear strength tests on the treated flocculated TTs. It was found that flocculation and thickening treatment increases the hydraulic conductivity of the treated TT which will result in the TT consolidating much faster than the untreated TT. The most important benefit of the flyash addition is the increase in shear strength and hydraulic conductivity of the flyash-treated TTs. The benefit of the freezing/thawing treatment processes coupled with flyash treatment is the increase in the compressibility and hydraulic conductivity at effective stresses lower than 100 kPa and void ratios greater than 1.2, respectively. This will facilitate earlier progressive reclamation required to support hydraulic sand capping. [ABSTRACT FROM AUTHOR]

With ongoing shale oil and gas exploration and development across the world, the sedimentology of deep‐water fine‐grained sedimentary rocks remains an important focus for research. In deep‐lacustrine settings, in particular, mud‐grade sediments are distributed widely. However, the very fine particle size of mud‐grade sediments limits the clear identification of micro‐sedimentary structure; the mud‐grade sediments are in most facies models believed to be deposited via suspension settling in deep‐lacustrine settings. In this study, thin‐section observations, advanced mineral identification and characterization system analyses, scanning electron microscopy observations and three‐dimensional reconstruction analysis by a focused ion beam‐electron beam dual‐beam system were conducted on deep‐lacustrine mud‐grade sediments of the Chang 73 sub‐member of Triassic Yanchang Formation in the Ordos Basin. Through this multi‐proxy approach, evidence of bedload transport of the mud‐grade sediments in the deep‐lacustrine settings is provided. During the deposition of deep‐lacustrine sediments, a significant amount of volcanic material within the mud‐grade sediments provided large quantities of high‐valence metal cations into the lake waters, which promoted the formation of flocs through electrostatic forces. Subsequently, these flocs are transported as bedload and deposited on the substrate, forming numerous floccule ripples in the deep‐lacustrine settings. When floccule ripples form, the flocs continuously pass over the ripple crests under the action of underflow and accumulate downward along the sloping surface of the floccule ripples, developing multiple foresets. Lateral migration and frontal progradation of foresets results in multiple stacked and laterally‐connected foresets, ultimately controlling the accumulation and preservation sites of these deep‐lacustrine mud‐grade sediments. The discovery of floccule ripples and foresets confirms a dynamic deep‐lacustrine setting, in which the mud‐grade particles can be transported as bedload under the action of underflow and then deposited. A new understanding of the sedimentary process of deep‐lacustrine mud‐grade particles provides a theoretical basis for clarifying the distribution of mineral composition and organic matter content in mud‐grade sediments. It further supports the prediction of favourable shale oil/gas reservoirs, promoting the efficient exploration and development of shale oil and gas resources, globally. [ABSTRACT FROM AUTHOR]

To investigate the flocculation and sedimentation effects of different single and composite flocculants on copper tailings slurry, traditional inorganic flocculant aluminum sulfate, polymeric inorganic flocculant polyaluminum chloride (PAC), and organic flocculant anionic polyacrylamide (APAM) were selected for experiments. Both single-flocculant tests using all 3 flocculants and composite-flocculant tests using the 2 inorganic flocculants mixed with APAM were conducted. Subsequently, the flocculated copper tailings slurry was tested for cement solidification. Results show that, under the same dosage, the flocculation performance of the 3 flocculants follows the order of APAM>PAC>aluminum sulfate. In the composite tests, the optimal combination of each flocculant resulted in better sedimentation than using them individually. The compressive strength of the solidified copper tailings after flocculation increased by a minimum of 2. 4 times at all curing ages. Among the single flocculants, the copper tailings solidified with aluminum sulfate exhibited the highest compressive strength at all curing ages, while APAM had the lowest. For composite flocculants, the combination of aluminum sulfate and APAM produced a higher compressive strength in the solidified copper tailings compared to the PAC and APAM combination. [ABSTRACT FROM AUTHOR]

Downstream costs represent one of the main obstacles to enabling microalgae to become widespread. The development of an economical, easily scaled-up strategy could reduce the overall process costs. Here, different flocculants were tested on different microalgae strains and a cyanobacterium. The results indicate that flocculation could be an alternative to centrifugation, as CaCl2 induced a complete flocculation of green and red marine strains (96 ± 4% and 87.0 ± 0.5%, respectively), whereas Chitosan was the only agent able to induce flocculation on the cyanobacterium (46 ± 1%). As for the thermoacidophilic red microalga, 100% flocculation was achieved only by increasing the pH. Carotenoids were extracted from the flocculated biomass, and the strategy improved with the use of the wet biomass. The results indicate that flocculation does not affect carotenoid yield, which is at least the same than that obtained upon centrifugation and extraction from the wet biomass. Then, for the first time, the biological activity of the extracts obtained from the flocculated biomasses was evaluated. The results indicate that only the green microalga extract shows increased antioxidant activity. In conclusion, this work highlights that a general downstream procedure cannot be developed for microalgae strains but should be rationally tailored. [ABSTRACT FROM AUTHOR]

The wastewater treatment process for middle rank coal employed coagulation-flocculation technology with bio coagulants to efficiently reduce the concentration of contaminants. This method utilized Moringa oleifera L. seed powder as the main bio coagulant, in addition to papaya seeds (Carica papaya Linn.) and Ambon banana peel waste (Musa paradisiaca var.) as secondary bio coagulants, which are combined with the main bio coagulant. The aim of this study was to determine the characteristics and effectiveness of bio coagulant compounds obtained from plants and waste materials. The study objective was also to investigate the effectiveness of combining biocoagulants derived from Moringa oleifera L., Carica papaya, and Musa paradisiaca var. in treating coal effluent. Biocoagulant is a natural alternative to chemicals like aluminum sulfate (Alum) that are detrimental to the environment. It is present in the ecosystem and serves as a substitute for these hazardous substances. The results revealed that the optimal dosage for combining bio coagulants was 1 gram per liter, with a composition ratio of 2 parts primary bio coagulant to 1 part auxiliary bio coagulant. The analysis of water pollutants showed a reduction in turbidity and total suspended solid (TSS) by 99.26% and 99.11% respectively. Additionally, there was a decrease in the levels of heavy metals iron (Fe) and manganese (Mn) by 98.71% and 99.88% respectively. [ABSTRACT FROM AUTHOR]

Based on CFD-PBM coupling simulation approach, the flocculation and settling behavior of iron tailings in the lab-scaled deep cone thickener with a diameter of 600 mm is simulated, where the turbulence and multiphase Is described by RNG kε; model and Eule--Euler model, respectively. The flocculation of line mineral particle is described by the proposed flocculation dynamics model. The effect of the feed concentration on the complex movement of particles is investigated. The results indicate that the mean Hoc size at the feed well outlet first increases and then decreases wkh the increase of the feed concentration in a certain range of feed concentration. The iron tailings have a better flocculation performance when the feed concentration is about 8%. The settling rate of the flocs decreases with the increase of the feed concentration, and the difference in settling rate of flocs of different sizes gradually decreases. This investigation can provide a theoretical basis for revealing the influence mechanism of concentration characteristics on the flocculation and settling behavior of tine mineral particles, and guide the technical control of feed concentration of a thickener. [ABSTRACT FROM AUTHOR]

The coagulation and flocculation properties of chitosan, an organic biopolymer derived from chitin, have been researched as an alternative to synthetic polymers and inorganic metal salt coagulants currently used in water and wastewater treatment. In an effort to encourage further research into the practical uses of chitosan as green chemistry in water and wastewater treatment and to promote the efficacious removal of microbial contaminants in drinking and wastewater, we have summarized the current state of research pertaining to the treatment of microorganisms in water and wastewater. A search of PubMed revealed 720 possible titles and abstracts, of which 44 full-text articles were identified as matching the eligibility criteria for inclusion in this systematic review. Results are presented based on the type of water matrix treated (i.e., drinking water, wastewater, and recreational waters) and a summary table providing details on the types and forms of chitosan utilized and the treatment mechanisms and processes described in the study. We find chitosan to be an effective coagulant, flocculant, and adsorbent for removing microbes from water and wastewater; some modified forms of chitosan can inactivate microbes and achieve disinfection, such as those containing metals like silver and antimicrobial chemicals like quaternary ammonium compounds or other strong oxidants, and use with filtration or electrochemical processes can achieve extensive reductions in microbes to meet performance targets of the World Health Organization. [ABSTRACT FROM AUTHOR]

Turbidity flows are known to be affected by the density difference between sediment plumes and the surrounding water. However, besides density, other factors could lead to changes in flow propagation. Such a factor is the presence of suspended organic matter. Recently, it was found that flocculation does occur within plumes upon release of a sediment/organic matter mixture in a lock exchange flume. In the present study, mineral sediment (illite clay) was released into the outflow compartment containing water and synthetic organic matter (polyacrylamide flocculant). Even though the density of water was barely affected by the presence of flocculant, flow head velocity was observed to be larger in the presence of flocculant than without. Samples taken at different positions in the flume indicated that flocs were created during the small current propagation time (about 30–60 s) and that their sizes were larger with higher flocculant dosage. The size of flocs depended on their positions in the flow: flocs sampled in the body part of the flow were larger than the ones sampled at the bottom. All these properties are discussed as a function of sediment–flocculant interactions. [ABSTRACT FROM AUTHOR]

Background: Oil compromises graft outcomes via inflammation, which accounts for the unpredictability of volume retention rates as low as 20%. Existing techniques for oil removal are relatively inefficient. In this study, a novel approach was taken to prepare concentrated deoiled fat (CDF) by utilizing flocculation and centrifugation to remove the oil. The hypothesis put forward in this study was that CDF would exhibit improved volume retention and quality by enhancing purification efficiency and reducing inflammation. Methods: This basic research involved both in vitro and in vivo experiments using samples obtained from women who underwent abdominal liposuction. The CDF was prepared by flocculation and centrifugation. In the vitro experiments, the microstructure of fat was assessed using Calcein acetoxymethyl ester (AM) staining for living cells and propidium iodide (PI) staining for dead nuclei in two groups: Coleman fat group and CDF group. Additionally, the glucose uptake capacity of these two groups was evaluated using the glucose transport test (GTT). In the vivo experiments, the study included three groups: two experimental groups (low-volume concentrated deoiled fat, LCDF; high-volume concentrated deoiled fat, HCDF) and one control group (Coleman fat), with 10 healthy female BALB/c nude mice in each group, 1ml of the graft was injected subcutaneously to each mouse. After 8 weeks, the fat grafts were harvested and subjected to volume evaluation, HE staining and immunostaining for perilipin to assess graft outcomes. Results: In the vitro experiments, the concentration rate of the CDF was found to be 79.6% that of Coleman fat, with 15.1% more oil separated. Cell viability, as assessed by AM/PI staining, did not show a significant difference between the two grafts, but the results of the GTT showed that the tissue viability of the CDF was higher than that of Coleman fat. In the vivo experiments, the CDF had higher volume retention than Coleman fat, as measured by water displacement. Histopathologic scoring indicated that HCDF group and LCDF group had a more intact fat structure with fewer vacuoles, inflammation, and fibrosis compared to Coleman fat. Additionally, the percentages of perilipin-positive area in the LCDF group and HCDF group were higher than in the Coleman group, indicating improved graft quality and outcome with the use of concentrated deoiled fat. Conclusions: "Concentrated deoiled fat" refers to an autologous fat graft from which oil has been removed by flocculation and centrifugation. This process increases volume retention and viable cells and decreases infiltrated inflammatory cells. Level of Evidence V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. [ABSTRACT FROM AUTHOR]

Biological treatment is currently a favorable option to treat wastewater due to its environmentally friendly methods and minimal toxic by-products. The majority of biological wastewater treatment uses bacteria as treatment agents, which are known to have excellent capabilities for removing various pollutants. Researchers have extensively explored the use of extracellular polymeric substances (EPSs) generated by bacteria in wastewater treatment. This review focuses on the sources of EPSs, factors influencing their production, and their role in wastewater treatment. Bacterial species, nutrient availability, pH, temperatures, and the presence of toxins were mentioned to be the factors influencing EPS production by bacteria in wastewater treatment. Produced EPSs by bacteria may promote the aggregation, adsorption, decolorization, and degradation of pollutants. This review highlights the challenges of discovering new potential bacterial species and complex EPS extraction methods, as well as the importance of mass production for larger-scale applications. [ABSTRACT FROM AUTHOR]

The vacuum-assisted prefabricated horizontal drain offers a promising method for strengthening soil slurry, allowing simultaneous filling and vacuum-dewatering via staged construction. However, there is limited research on the unique characteristics of staged filling. This study aims to investigate the vacuum consolidation process of staged-filled soil slurry through laboratory model tests and numerical simulations, also assessing the impact of anionic polyacrylamide. Comparative analyses are conducted between vacuum consolidation with and without anionic polyacrylamide, as well as self-weight consolidation without anionic polyacrylamide. Results reveal contour lines of excess pore pressure, water content, and soil strength forming an ellipse around the prefabricated horizontal drain board. During the consolidation process, a higher degree of consolidation, lower water content, and higher soil strength were observed closer to the prefabricated horizontal drain board. After treatment, the uppermost filling layer exhibits an average water content that was approximately 40% higher than the lower filling layer, and its average strength was about 60% lower. This discrepancy is primarily due to the absence of sealing on the top surface and the relatively short vacuum consolidation time caused by staged filling. The introduction of anionic polyacrylamide-induced flocculation significantly improves the initial consolidation rate but minimally affects the dewatering capacity of vacuum preloading. Using flocculant can enhance both the staged filling rate and soil strength (by 1–2 times). Additionally, employing a staggered arrangement between different prefabricated horizontal drain layers is advisable to prevent top-down penetration in areas with low soil strength.

A novel flocculant combination was developed for the treatment of fracturing flowback fluid of Linxing coalbed methane field, with polysilicic acid polymerized iron sulfate as the coagulant and acrylamide and acrylic acid-1,2-ethylenetriammonium chloride copolymer as the coagulant aid. The optimal conditions for flocculation treatment of gas layer fracturing flowback fluid were optimized and screened, and the flocculation mechanism was analyzed. The results showed that the best flocculation effect was achieved when the mass concentration of the agent was 300-400 mg/L, the pH was 7.5-8.5, the temperature was 25-35 ℃, the mixing strength was 1 300-1 500 s-1, and the flocculation time was 20-30 s. Under optimized conditions, the novel flocculant combination was applied to the Linxing coalbed methane backflow liquid treatment station. The suspended solids mass concentration in the effluent was stabilized at 6-8 mg/L, the oil mass concentration was stabilized at 3-5 mg/L, and the median particle size was stabilized at 1.4-1.7 μm. The effluent quality met the reinjection water control indicators at reservoir air permeability of [0.5, 2.0) μm2 of the Technical Requirements and Analysis Methods for Water Quality Indicators in Clastic Rock Reservoirs (SY/T 5329-2022). The effluent could be directly reinjected into the ground. The novel flocculant combination has broad prospects for application and promotion.

Plastic was produced massively, especially using polyvinyl chloride (PVC) as a raw material. Unfortunately, this condition cause affects the environment, which creates a new pollutant issue. It is essential to study the removal of PVC microplastics in current water treatment processes. The study of wastewater treatment can be achieved using electrocoagulation, which has several benefits, including low-cost, simple chemicals, and accessible equipment operation. This research investigated the study of the removal of PVC microplastics from wastewater by electrocoagulation. The new potential of the electrocoagulation technique using Al-Al electrodes was studied systematically at various variations, i.e., electrolysis time, electrolyte concentration, initial pH, coagulation speed, and electrolyte type. The results showed that the PVC microplastics removal efficiency reached 100% after electrolysis for 60 min, electrolyte concentration of 0.01 mol/L, initial pH of 7, coagulation speed of 500 rpm, the type of electrolyte used was NaCl at a flocculation speed. These optimum conditions also reduced the value of turbidity of wastewater samples from 1.39 ± 0.02 to 1.10 ± 0.05 NTU. The results of this study provide an engineering perspective in optimizing operational parameters for removing PVC microplastics in aquatic environments.

Abstract In this study, the effect of presence and concentration of two synthetic polymeric flocculants with different charging mechanisms (anionic and cationic) on surface quality and abrasive tool wear in polishing process of building stones was investigated. The polishing tests were performed in laboratory scale on two stone samples (granite and marble). An index, entitled improvement index (I) was defined for evaluating the effectiveness of flocculants on surface quality and abrasive tool wear. The results revealed that flocculation process had a noticeable effect on enhancement of surface quality and reduction of abrasive tool wear for both stone samples. The cationic flocculant was more effective for granite sample and anionic flocculant was more effective for marble sample. The granite particles mainly exhibit negative surface charge while the marble particles have positive surface charge in the pH range of wastewater used for polishing tests. Therefore, charge neutralization mechanism plays a major role in flocculation process of granite and marble samples. It was found that the use of flocculation process for treatment of wastewater in stone processing plants leads to increase of abrasive tool lifespan and more high-quality products.

Coagulation/Flocculation (C/F) process aims to efficiently eliminate turbidity, TSS, COD, BOD, toxic metals, phosphates, and UV254nm from wastewater. Both natural and synthetic coagulants, used alone or in conjunction with flocculants, play crucial roles in this treatment. This review summarizes recent trends in coagulants for wastewater treatment, highlighting a wide array of inorganic and organic coagulants that have demonstrated significant efficacy based on reviewed studies. Notably, Crab Shell Bio-Coagulant (CS) excels in turbidity remov5al, achieving a remarkable 98.91% removal rate, while oak leaves protein shows superior performance in TSS and COD removal. Synthetic inorganic coagulants like PALS, PSiFAC1.5:10:15, and PAPEFAC1.5-10-15 demonstrate outstanding turbidity removal rates, over 96%. POFC-2 coagulant stands out for efficiently removing TSS and COD from domestic wastewater, achieving up to 93% removal for TSS and 89% for COD. Moreover, the utilization of FeCl3 as an inorganic coagulant alongside chitosan as an organic flocculant shows promise in reducing turbidity, COD, and polyphenols in wastewater from vegetable oil refineries. PE-2, a novel organic coagulant, demonstrates exceptional efficacy in eliminating turbidity, TSS, COD, and BOD from sugar industry wastewater. Chitosan shows effectiveness in removing TOC and orthophosphates in brewery wastewater. Additionally, CTAB shows high efficiency in removing various toxic metal ions from wastewater. The hybrid coagulants: PAAP0.1,0.5 and PPAZF accomplish exceptional turbidity removal rates, approximately 98%.

Microplastics (MP), fragments of plastic generally defined as, less than 5 mm in size, originating from various urban sources, have become a significant environmental concern due to their widespread presence and potential impacts on ecosystems. This study investigates the efficiency of an advanced wastewater treatment plant discharging into the Mediterranean Sea in removing MPs from wastewater. The plant processes wastewater through a series of treatment stages, including screening, desanding, coagulation/flocculation, biological filtration, and sludge incineration. Samples were collected and analysed during three distinct campaigns (dry, rainy, and touristic seasons) to assess the plant's performance under varying conditions. Using matrix-representative sampling methodologies and Focal Plane Array micro Fourier-Transform Infrared Spectroscopy (FPA-µFT-IR) for MP quantification, the study measured MP concentrations and removal rates. The treatment plant demonstrated high removal rates of microplastics across different periods. Using a mass balance approach, the removal efficiency during the dry sampling period was 99.85%. In the rainy campaign, the efficiency slightly decreased to 99.11% due to increased runoff, while during the touristic period, the efficiency peaked at 99.95%. Polyester was identified as the predominant polymer type. The primary treatment stages, particularly coagulation/flocculation and lamellar settling, are most effective in MP removal. The majority of MPs are retained in the sludge, which is subsequently incinerated, preventing environmental discharge. This research demonstrates that a WWTP employing advanced treatment processes is not a source of MP to the environment but rather a sink. Despite variations in influent MP concentrations across different seasons, the plant consistently maintained high removal rates, effectively mitigating MP pollution. In this study, sludge incineration further ensured that MPs were prevented from entering the environment. [ABSTRACT FROM AUTHOR]

Homogenous advanced oxidation processes (AOPs) based on transition metal catalysts toward the activation of H2O2 to hydroxyl radical (•OH) have been widely applied to organic pollutants removal, such as Fenton and Fenton-like processes. These transition metal catalysts mostly flocculate as the pH increases. It's worth noting that the formed transition metal flocs are complex heterogeneous aggregations with active substances, providing diverse reaction spaces and interfaces. However, it is a challenge to distinguish the roles of transition metal flocs in the organic pollutants removal from homogeneous catalytic reactions. Herein, we unveiled a pathway for the long-lasting removal of organic pollutants via Cr flocs adsorbed with •OH (HO•-Cr flocs) using a stepwise method. First, adsorbed •OH (•OHads) within the HO•-Cr flocs was proved to be the active site forming hydrogen bond (H-bond) and van der Waals force with organic pollutants. Then, the presence of switchable electron transfer between Cr and OH groups within the HO•-Cr flocs was revealed, contributing to the persistent existence of •OHads and consequently ensuring the long-lasting organics removal. Further, this removal pathway of organic pollutants was confirmed during the leather wastewater treatment. These findings will complement a different pathway for organic pollutants removal via transition metal flocs and extend the lifetime of homogeneous AOPs based on transition metal catalysts, providing significant implications for their design and optimization. [ABSTRACT FROM AUTHOR]

This study addresses the challenge of the reverse effect observed in the dewatering process of waste slurry as poly-aluminum chloride (PAC) dosages increase. It investigates the flocculation mechanism of PAC at varying dosages in a high-water-content slurry using molecular dynamics simulation methods. The results indicate that PAC molecules primarily adsorb montmorillonite particles while exerting negligible influence on quartz. Dewatering efficiency is influenced by the adsorption-repulsion interaction at the PAC-montmorillonite interface. Efficiency increases with PAC dosage up to an optimum level due to enhanced adsorption but decreases thereafter due to increasing repulsion. Within this optimal range, montmorillonite interfaces exhibit a higher negative charge, facilitating stable PAC adsorption and leading to increased aggregation of montmorillonite particles, thereby forming flocs. The adsorption capacity of PAC on montmorillonite particles escalates with dosage until achieving the optimal flocculation effect. However, surpassing this optimal dosage prompts repulsion among outer PAC molecules, gradually causing montmorillonite particles to separate due to repulsion, thereby weakening the flocculation effect. This research provides theoretical support for the flocculation and dewatering of PAC in high-water-content waste slurry, emphasizing the rational and cost-effective addition of PAC in practical applications. [ABSTRACT FROM AUTHOR]

Attapulgite (ATP) is a biocompatible clay mineral that efficiently absorbs water. It is widely used in water treatment due to its environmental friendliness and cost‐effectiveness. This study aimed to develop a volume‐expansion structure‐based attapulgite flocculant (VES‐ATP) using aluminum salt and attapulgite (ATP) under alkaline conditions, specifically for the treatment of water containing low levels of phosphorus. The VES‐ATP was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. The removal of phosphorus by the VES‐ATP was conducted by varying the mass ratio of Al to attapulgite (denoted as RmAl/mATP), ATP dosage, and pH. The results showed that the VES‐ATP had a good expansion and dispersibility in the presence of alkalized aluminum species. The basicity as the molar ratio of OH to Al (0.8 or 1.6) determined the expansion feasibility, and the coverage degree of Al onto ATP, as indicated by the mass ratio of Al to attapulgite (denoted as RmAl/mATP), determined Al flocculation efficiency. Higher values such as RmAl/mATP = 4:1 and 2:1 may result in a better flocculation. Low phosphorus treatment was successfully achieved through Al flocculation and ATP adsorption, including complexation, hydrogen bonding, and electrostatic attraction. As expected, the VES‐ATP generated larger size flocs with a bigger fractal dimension than that with the sole Al flocculation. As a result, the total phosphorus could be reduced to the level below 5 μg/L. It is more efficient in the pH range of 5–9. Overall, the coupling of aluminum and attapulgite has significantly enhanced both purification capabilities of phosphorus. Practitioner Points: Polymeric aluminum‐modified attapulgite was efficient for removal of low phosphorus concentration.Phosphorus concentrations can be reduced to below 5 μg/L.Polymeric aluminum and attapulgite are both safe, and this technology is suitable for water treatment. [ABSTRACT FROM AUTHOR]