Cationic Coagulant Research Articles

Serum Biomarkers in Bullous Pemphigoid: A Systematic Review.

Bullous pemphigoid (BP) is the most common type of subepidermal blistering disease, usually observed in the elderly population, with a mean age of presentation between 66 and 83 years. BP is a psychosocially ladened disease, with many patients experiencing negative body image, social isolation, and depression. The identification and validation of biomarkers in BP may further the understanding of disease pathogenesis, provide objective measures in assessing efficacy in clinical trials, and identify new targets for targeted therapy. Two databases (Medline and Embase) were searched from database inception to September 2023. All published articles reporting on biomarker levels of BP patients in serum compared to healthy controls were included. A total of 877 unique articles were identified, resulting in the inclusion of 62 case-control studies reporting on a total of 1837 patients and 140 unique biomarkers. Biomarkers were categorized into T-cell mediated, B-cell mediated, innate immune system, and coagulation cascade pathway. The most notable biomarkers identified include increases in anti-BP180/230 immunoglobulin (Ig)G/E, total IgE, TNF-α, B-cell activating factor, interleukin-31, eosinophil cationic protein, MMP-9, and coagulation cascade biomarker levels. The results of this review provide the greatest support for a role of anti-BP180/230 autoantibodies, Th2 cells, eosinophils, and the coagulation cascade in the pathogenesis of BP. The pathogenesis of BP has an underlying autoimmune etiology centred around the production of autoantibodies against BP180/230, but increased Th2, eosinophil and coagulation cascade activity may be contributory.

FABRICATION OF HIGH STRENGTH PAPER FROM DIFFERENT TYPES OF PHOSPHORYLATED FIBERS USING HOT PRESSING AND FORMING AGENTS

Phosphorylated fibers offer a broad range of applications, particularly in thermal insulation, notably with wood fibers, provided they exhibit improved mechanical characteristics. Despite encountering challenges in applying traditional papermaking methods, the creation of paper or board sheets with phosphorylated pulp fibers remains a challenge. Findings suggest that phosphorylation-modified fibers show increased roughness. Moreover, in comparison with unbeaten kraft sheets (KF) and thermomechanical pulp sheets (TMP), those made from phosphorylated kraft fibers (PKF), using a cationic coagulant and a flocculant, demonstrate significant enhancements in burst index, break index, and tensile energy absorption by 2.12 times, 1.7 times, and 2.77 times, respectively. Similarly, phosphorylated TMP sheets, prepared with a dual polymeric system (coagulant/flocculant), exhibit improvements of 1.42 times, 1.33 times, and 1.82 times, respectively, in these properties. The study emphasizes the ameliorating effect of cationic polymeric agents on the charge impact of phosphorylated fibers on overall sheet quality, while also highlighting the substantial influence of hot-pressing lignin-containing paper on all determined physical properties.

Chemical recovery of magnesium from the Dead Sea and its use in wastewater treatment

Abstract The objective of this study was to establish a suitable chemical process to recover magnesium compounds from Dead Sea water using a selective precipitation process. The recovered magnesium hydroxide (Mg(OH)2) and magnesium chloride (MgCl2) are applicable for wastewater treatment processes since they can effectively remove total suspended solids (TSS) and chemical oxygen demand (COD). Magnesium salts recovered from Dead Sea water were compared with cationic polyacrylamide (PAM) and inorganic salts, including aluminum sulfate Al2(SO4)3, ferric chloride (FeCl3), and ferrous sulfate (Fe2SO4) to investigate the removal efficiency of TSS and COD from wastewater using a chemical precipitation method by using coagulation and flocculation process. Results show that Mg(OH)2 yielded the highest TSS and COD removal efficiencies of 59 and 57%, respectively, with a wastewater pH of 11.5. MgCl2 yielded lower removal efficiencies of 46 and 44%, respectively; at pH 10.5, lower magnesium concentration doses were needed. The most effective chemical precipitation method for removal involved cationic PAM coagulants, resulting in an 86% reduction in TSS and a 65% reduction in COD. Combining commercial Fe2SO4 and MgCL2 recovered from Dead Sea water reduced up to 90 and 73% of TSS and COD, respectively.

Use of biochar and a post-coagulation effluent as an adsorbent of malachite green, beneficial bacteria carrier, and seedling substrate for plants belonging to the poaceae family

Wastewater treatment plants produce solid and semi-solid sludge, which treatment minimises secondary environmental pollution because of wastewater treatment and obtaining new bioproducts. For this reason, in this paper, the co-pyrolysis of biogenic biomasses recovered from a biological reactor with immobilised fungal and bacterial biomass and a tertiary reactor with Chlorella sp. used for dye-contaminated wastewater treatment was carried out. Biogenic biomasses mixed with pine bark allowed the production and characterisation of two types of biochar. The raw material and biochar were on the “in vitro” germination of Lolium sp. seeds, followed by adsorption studies for malachite green (MG) dye using the raw material and the biochar. Results showed that using 60 mg L−1 of a cationic coagulant at pH 6.5 allowed for the recovery of more than 90% of the microalgae after 50 min of processing. Two biochar resulted: BC300, at pH 5.08 ± 0.08 and BC500, at pH 6.78 ± 0.01. The raw material and both biochars were co-inoculated with growth-promoting bacteria; their viabilities ranged from 1.7 × 106 ± 1.0 × 101 to 7.5 × 108 ± 6.0 × 102 CFU g−1 for total heterotrophic, nitrogen-fixing and phosphate-solubilising bacteria. Re-use tests on Lolium sp. seed germination showed that with the post-coagulation effluent, the germination was 100%, while with the biochar, with and without beneficial bacteria, the germination was 98 and 99%, respectively. Finally, BC500 adsorbed the highest percentage of malachite green at pH 4.0, obtaining qecal values of 0.5249 mg g−1 (R2: 0.9875) with the pseudo-second-order model.

Effects of different modifying agents on the preparation and properties of coagulants derived from excess sludge.

The contents and kinds of oxygen-containing functional groups are very significant when preparing cationic hydrochar coagulants via graft copolymerization. Herein, the hydrothermal conditions to produce sludge-based hydrochar (SBC) precursors were optimized by introducing different kinds and amounts of modifying agents (i.e., HCOOH, citric acid (CA), H2SO4, and H2O2), then the surface properties and flocculation performance of derived cationic coagulants (SBC-g-DMC) were studied. Results showed that the utilization of four modifiers raised the acidic groups on the SBC surface; thereinto, the presence of CA could evidently increase the content of phenolic hydroxyl groups. After DMC monomer grafting, the formed coagulants possess positive zeta potentials over a wide pH range (i.e., 3.0 ~ 11.0), showing a typical cationic property. The grafting ratio and efficiency, as well as the cationic degree of coagulants prepared with different SBC precursors follow a descending order of SBCCA-g-DMC > [Formula: see text]-g-DMC > SBCHCOOH-g-DMC > [Formula: see text]-g-DMC; thus, SBCCA-g-DMC coagulant with the best grafting result shows a superior flocculation performance. When a dosage of 4mg/L was adopted, the average turbidity removal rate of SBCCA-g-DMC could reach up to 94.44%. Meanwhile, due to the possible and robust oxidation with the initiator, H2O2 seems not a perfect modifier for SBC preparation. This study could provide an essential reference for the optimal synthesis of SBC and its based coagulants for organic matter recovery and pollutant removal.

Synergistic coagulation effect of the cationic coagulant and anionic flocculant on fluorite tailings

Synergistic coagulation effect of the cationic coagulant and anionic flocculant on fluorite tailings

Pilot-scale demonstration of dissolved organic nitrogen removal from an advanced water reclamation facility using enhanced coagulation

Most wastewater treatment facilities that satisfy stricter discharge restrictions for nutrients, remove dissolved inorganic nitrogen (DIN) species efficiently, leaving dissolved organic nitrogen (DON) to be present at a higher proportion (up to 85 %) of total nitrogen (TN) in the effluent. Discharged DON promotes algae growth in receiving water bodies and is a growing concern in effluent potable reuse applications considering its potential to form hazardous nitrogenous disinfection byproducts (N-DBPs). Enhanced coagulation is an established process in the advanced water treatment train for most potable reuse applications. However, so far, no information has been collected at the pilot scale to address DON removal efficiency and process implications by enhanced coagulation under real conditions. This study performed a comprehensive evaluation of DON removal from the effluent of the Truckee Meadows Water Reclamation Facility (TMWRF) by enhanced coagulation over the course of 11 months at the pilot scale. Three different coagulants (aluminum sulfate (alum), poly‑aluminum chloride (PACl), ferric chloride (FC)) and a cationic polymer coagulant aid (Clarifloc) were used. Optimum doses for each coagulant and polymer and ideal pH were determined by jar tests and applied at the pilot. Alum (24 mg/L) resulted in highly variable DON removal (6 % – 40 %, 21 % on average), which was enhanced by the addition of polymer, leading to 32 % DON removal on average. PACl (40 mg/L) and FC (100 mg/L) resulted in more consistent DON removal (on average 45 % and 57 %, respectively); however, polymer addition exerted minimal enhancement for these coagulants. Overall, enhanced coagulation effectively reduced DON in the tertiary effluent at the pilot scale. The treatment showed auxiliary benefits, including dissolved organic carbon (DOC) and orthophosphate removal.

Study of radical polymerization of diallyl monomer based on allyl bromide and piperidine

In this article, kinetic feature of N, N-diallylpiperidine bromide radical polymerization is investigated. Orders of reaction are determined by the monomer and by the initiator. Essential value in this regard acquire investigation of implementation mechanism on elementary acts of radical polymerization N-alkyl - N, N-diallylamines and their proton salts at initial extents of transformation in water and water-organic solutions. Specific cyclolinear polymerization of diallyl monomers salt allows excluding the act degraded transfer of the chain on monomer and gives the chance of receiving polymers with high molecular weight. Data of kinetic researches testify the lack of degradation inherent chain transfer. It is noted that polymerization rate decreases while adding monomer ethanol to water solution. NMR 13C-spectroscopic researches of the polymers received by radical polymerization of N, N-diallylpiperidine bromide testifies the existence in chains of macromolecules as to five - (48%), and six-membered cycles (52%) which are calculated from a ratio of intensity of signals of the corresponding carbon atoms. The combination of polymeric, surface active and electrolytic properties of the synthesized polymer leads to the new qualitative state possessing a number of specific features shown in conformational and electrochemical behavior of polymer solution. Finding these properties will cause assessment opportunities of synthesized polymer usage as cationic flocculants, coagulants, precipitators and other purposes. Therefore, as distinct from anion and nonionic flocculants, cationic flocculants show high efficiency on application of them for extraction of organic and colloidal pollution and sedimentation of the weighed particles. Besides big advantage of cationic flocculants is the absence of their corrosion action on metals.

Influence of the hydrophobicity of the starch-based coagulant on the coagulation of various pollutants in water and the study of its mechanism

<p indent="0mm">Parts of surface water in China, including some rivers and lakes, show the characteristics of micropollution containing excessive dissolved organic matter, which has become a key factor in restricting the improvement of water quality. Coagulation is one of the most popular technologies in the purification of surface water owing to its low cost and simple operation. However, traditional coagulants, including inorganic and organic synthetic polymer coagulants, usually show a low efficiency in removing organic micropollutants from surface water and pose the risk of secondary pollution. Furthermore, the molecular structures of organic micropollutants contain hydrophilic and a large number of hydrophobic groups. Considering these facts, in this study, starch (St), a natural polymer with the characteristics of environmental friendliness, wide source, and low cost, was used as the raw material and acrylamide and various quaternary ammonium salts containing different lengths of carbon chains were used as modifiers. Accordingly, four modified starch coagulants (CS-DMRCs) with the same charge density and good water solubility but different degrees of hydrophobicity were designed and fabricated using graft copolymerization. Kaolin particles, sodium humate (NaHA), and bovine serum albumin (BSA) were used as the simulated sources of inorganic colloids and different organic pollutants in the micropolluted turbid surface water. The effects of the hydrophobicity of four St-based coagulants on the removal of kaolin particles, NaHA, and BSA from their single, binary, and ternary pollutant aqueous systems were investigated systematically. Based on the apparent coagulation performance, the floc properties, including floc size, compactness, surface morphology, breakage and recovery behaviors, and the zeta potentials of the supernatants after coagulation, the coagulation mechanisms associated with the structural features of the St-based coagulants and treated pollutants were explored and discussed in detail. The St-based coagulants with a higher hydrophobicity showed better coagulation performance owing to the synergistic effects of charge neutralization, bridging flocculation, and hydrophobic association. In addition to these simulated water samples, a real micropolluted turbid surface water sample from the Jiuxiang River of Nanjing was tested and compared with the simulated water samples, further confirming the practicality of the hydrophobically modified cationic St-based coagulants. In summary, CS-DMRCs should have broad prospects in practical applications owing to their easy and simple fabrication and high efficiency in the purification of organic micropolluted turbid surface water.

Solid–Liquid Separation of Dairy Barn by Electrocoagulation with Cationic Polymer Coagulant

High–molecular-weight polymer coagulants are widely used in wastewater treatment combined with traditional inorganic coagulants to improve the solid–liquid separation efficiency. However, it is desirable to keep chemicals used in treatments at minimum levels for economic and safety reasons. This study aimed to increase the efficiency of two-stage electro- and chemical-coagulation treatment with a minimum chemical dosage for the separation of solids and liquid in dairy manure slurry for the safe composting of solids and safe discharge of wastewater. Accordingly, dairy manure slurry was treated with aluminum (Al) coagulants, such as polyaluminum chloride (PAC), aluminum chloride (AlCl3), and aluminum sulfate (Al2(SO4)3), PAC combined with the cationic polyacrylamide (CPAM), and PAC and CPAM combined with electrocoagulation (EC). Results revealed that PAC was the best among the Al coagulants evaluated for the reduction in turbidity in the liquid fraction at a dosage of 100 mg/L. PAC dosage was reduced to 40 mg/L when the treatments were combined with CPAM at a dosage of 40 mg/L, which was further reduced to 30 mg/L when treatments were combined with 5 min EC and 20 mg/L of CPAM dosage.

Influences of charge properties and hydrophobicity on the coagulation of inorganic and organic matters from water associated with starch-based coagulants

In this work, two series of binary graft cationic starch-based coagulants (CS-DMCs and CS-DMLs) with different hydrophobicities and charge densities (CDs) were prepared by graft copolymerization of acrylamide with 2-(methacryloyloxy)-N,N,N- trimethylethanaminium chloride and acryloyloxyethyl dimethyl benzyl ammonium chloride, respectively, on the starch (St) backbone. Kaolin particles, sodium humate (NaHA), and bovine serum albumin (BSA) were used as the simulated sources of inorganic colloidal particles and different organic pollutants in the micropolluted turbid surface water. The influences of the CD and hydrophobicity associated with the St-based coagulants on the removal of kaolin particles, NaHA, and BSA from single, binary, and ternary pollutant aqueous systems were investigated systematically. On the basis of the apparent coagulation performance, the floc characteristics, and the zeta potentials of the supernatants after coagulation, the coagulation mechanisms associated with the structural features of the St-based coagulants and the pollutants treated were explored and discussed in detail. The St-based coagulants with a higher CD and a stronger hydrophobicity showed better coagulation performance due to the synergistic effects of charge neutralization and hydrophobic association. The maximum efficiencies of the optimized St-based coagulant in removal of Kaolin, NaHA and BSA were 93.85%, 100% and 97.52% in their respective single pollutant systems. In addition to these simulated water samples, a real micropolluted turbid surface water tested and compared, further confirming the superiority of the hydrophobically modified cationic St-based coagulants, especially in the purification of organic pollutants in water.

Cationic Surfactant-Mediated Coagulation for Enhanced Removal of Toxic Metal–Organic Complexes: Performance, Mechanism, and Validation

Cationic Surfactant-Mediated Coagulation for Enhanced Removal of Toxic Metal–Organic Complexes: Performance, Mechanism, and Validation

Technical Assessment of Secondary Sedimentation Process in Copper Sulphide Tailings with the Presence of Clays, in Continental and Sea Water

Recovery of process water for recirculation is crucial, as the cost of adding additional fresh water is an economic constraint that is often prohibitive. Solid–liquid separation is a key process in the recovery of water resources. Therefore, research is needed to understand how fine particles, particularly quartz, kaolinite and sodium bentonite, impact the optimal separation process. In the present work, the effect of the presence of these clays in the solid–liquid separation of synthetic copper sulfide tailings is evaluated, quantifying the impact on the separation efficiency, considering the average settling rate and the turbidity of the supernatant. The physicochemical variables that control the suspension were monitored and the observed trends were explained by variations in properties such as zeta potential and pH. The characterization and quantification of the impact of the clays in the operation will allow us to lay the foundation for the development of a novel approach for the secondary treatment of the cloudy supernatant water of the thickeners. After the study, disparate effects on sedimentation efficiency could be distinguished depending on the type of clay and the water in which it is immersed. While in the case of tailings with the presence of kaolinite clays it is seen that the higher sedimentation efficiency occurs in the case of flocculation in distilled water, the salinity or presence of cationic coagulants is detrimental to it. In the case of tailings with the presence of bentonite clays, the sedimentation efficiency increases as there is a higher concentration of cationic salts (coagulation-synthetic sea water). In contrast, in the case of distilled water, the flocculation efficiency is very low, so it is recommended to add a cationic additive, which is supported by an associated low economic cost. In the case of tailings with the presence of ultrafine quartz content, a clear effect in the increase or decrease of sedimentation efficiency cannot be distinguished with the addition of flocculants, coagulants, or when working in sea water. Overall, the results suggest the convenience of splitting thickening and clarification as two distinct unit processes that may be treated using flocculant and salts, according to the fine mineral contents.

Utilization of Banana Pith Starch From Agricultural Waste As A Cationic Coagulant

The coagulation method is the most commonly used in water treatment. However, long-term use of chemical coagulants can increase the risk of Alzheimer's disease and neurotoxicity, in addition to harming organisms, lowering the pH of the water, corrosion of pipes, and the use of high doses of chlorine. The study synthesized banana pith starch from agricultural waste as a cationic coagulant for river water treatment. Banana pith starch was modified by grafting cations from GTA (3-Chloro-2-hydroxypropyl trimethyl ammonium chloride) into the backbone structure of starch using microwave radiation. Performance tests were carried out on variations in dose (4), speed (3), and stirring time (3). Parameters tested were turbidity, TDS, and color, with four replications. The study found that the synthetic cationic coagulant could reduce turbidity up to 94.4%, while the color and TDS were 87.46% and 57.33%, respectively. The variety of treatments seemed to work on all test parameters (p less than 0.05). However, the most effective treatment was at a dose of 300 ppm, stirring speed of 200 rpm, for 5 minutes. Research has succeeded in proving that banana pith starch can be modified into an effective cationic coagulant to remove colloid compounds in water. Abstrak: Saat ini metode koagulasi merupakan metode yang paling umum digunakan dalam pengolahan air. Namun, penggunaan koagulan kimia jangka panjang dapat meningkatkan risiko penyakit Alzheimer danneurotoksik, selain juga merugikan organisme, pH air menjadi rendah, korosi pipa, penggunaan clorin dosis tinggi. Penelitian bertujuan memanfaatkan pati empulur pisang dari limbah pertanian, sebagai koagulan kationik untuk pengolahan air sungai. Modifikasi pati empulur pisang dilakukan dengan cara mencangkokkan kation dari GTA (3-Chloro-2-hydroxypropyl trimetil amonium klorida) ke dalam struktur tulang punggung pati, menggunakan radiasi gelombang mikro. Pengujian kinerja dilakukan pada variasi dosis (4), kecepatan (3), dan waktu pengadukan (3). Parameter yang diuji adalah kekeruhan, TDS, dan warna, dengan empat kali ulangan. Penelitian mendapatkan bahwa koagulan kationik hasil sintesis mampu mereduksi kekeruhan hingga 94,4%, sedangkan warna dan TDS sebesar 87,46% dan 57,33%. Ragam perlakuan terlihat bekerja pada semua parameter uji (p kurang dari 0,05). Namun begitu, perlakuan paling efektif pada dosis 300 ppm, kecepatan pengadukan 200 rpm, selama 5 menit. Penelitian telah berhasil membuktikan bahwa pati empulur pisang dapat dimodifikasi menjadi koagulan kationik yang efektif untuk menghilangkan senyawa koloid dalam air.

Potential of Moringa Oleifera Seed as a Natural Adsorbent for Wastewater Treatment

The present study deals with the appropriateness of the coagulation process using natural coagulant Moringa oleifera seed. Natural coagulants are useful for the treatment of wastewater because of its sustainability, cost-effectiveness, non-toxicity and lesser quantity of sludge formation. M. oleifera seed having a chemical composition of polypeptides having 6 amino acids like arginine acid, methionine acid, glutamic acid, phenylalanine, threonine, and histidine. M. oleifera is also known as a cationic polyelectrolyte and having molecular weight 6,000 to16,000 Dalton. The main objective of research work is the application of the M. oleifera seed as a natural adsorbent to treat synthetic dairy wastewater. The effects of pH, agitation time, the dose of sorbent and efficacy of M. oleifera seeds kernel for turbidity removal was assessed. M. oleifera seed eliminates turbidity 95 % and colour 94 % using 0.22 gm pod powder, and 0.2 L of 1.0 g/L synthetic dairy wastewater. Naturally dried M. oleifera seeds remove turbidity 95 %, sundried seeds remove turbidity 52 % and oven-dried seeds 45 %. As naturally dried M. oleifera pod having more surface area for adsorption and inter-particulate bridging which extract the extra active ingredients. pH range between 5 and 8 is more suitable to degrade the turbidity and colour. It is concluded that in the presence of an aqueous soluble cationic coagulant protein has great potential to remove the turbidity and colour of wastewater.&#x0D; HIGHLIGHTS&#x0D; &#x0D; oleifera seed having a chemical composition of polypeptides having 6 amino acids like arginine acid, methionine acid, glutamic acid, phenylalanine, threonine, and histidine&#x0D; oleifera seeds consist of crude fiber, lignin, hemicellulose, and cellulose. It also contains amino functional groups (R-NH3), carboxyl group (C=O), and fiber carbonaceous. The functional group present in M. oleifera seeds is dissociated during the adsorption process at various pH&#x0D; oleifera has good property of coagulation-flocculation (C-F)&#x0D; The effectiveness of naturally dried seed kernel is more effective than other seed kernels&#x0D; &#x0D; GRAPHICAL ABSTRACT

Chitosan Coagulation Pretreatment to Enhance Ceramic Water Filtration for Household Water Treatment.

Viruses are major contributors to the annual 1.3 million deaths associated with the global burden of diarrheal disease morbidity and mortality. While household-level water treatment technologies reduce diarrheal illness, the majority of filtration technologies are ineffective in removing viruses due to their small size relative to filter pore size. In order to meet the WHO health-based tolerable risk target of 10−6 Disability Adjusted Life Years per person per year, a drinking water filter must achieve a 5 Log10 virus reduction. Ceramic pot water filters manufactured in developing countries typically achieve less than 1 Log10 virus reductions. In order to overcome the shortfall in virus removal efficiency in household water treatment filtration, we (1) evaluated the capacity of chitosan acetate and chitosan lactate, as a cationic coagulant pretreatment combined with ceramic water filtration to remove lab cultured and sewage derived viruses and bacteria in drinking waters, (2) optimized treatment conditions in waters of varying quality and (3) evaluated long-term continuous treatment over a 10-week experiment in surface waters. For each test condition, bacteria and virus concentrations were enumerated by culture methods for influent, controls, and treated effluent after chitosan pretreatment and ceramic water filtration. A > 5 Log10 reduction was achieved in treated effluent for E.coli, C. perfringens, sewage derived E. coli and total coliforms, MS2 coliphage, Qβ coliphage, ΦX174 coliphage, and sewage derived F+ and somatic coliphages.

Features of the discharge of zinc in the background solution of sodium sulphate under stirring conditions

The production technology of hydrometallurgical zinc uses various surfactants to thicken pulps, stabilise the electrolysis process, and obtain high-quality cathode deposits. Numerous researches were conducted to study the cathodic and anodic processes in a wide range of the composition of aqueous solutions using various solid electrodes in the absence of intense stirring of the electrolyte and with a high contribution of the migration component of the discharge of metals. This approach to the study of the surfactants’ influence rarely provided a high degree of statistical reliability in observing the effect of differently charged surfactants on electrode processes, which is of great importance in the hydrometallurgical production of zinc. In this work, the task was to practically eliminate the contribution of the migration component due to the followingfactors: conducting electrolysis in a background solution of sodium sulphate, organising electrolyte stirring, performing calculations of current densities at the beginning of electrolysis, and establishing polarisation curves at an increased potential sweep rate from 20 to 100 mV/s. This approach provided a greater degree of statistical reliability in presenting the mechanism of the effect of additions of cationic and anionic surfactants during the stage of zinc discharge on a solid electrode, which was the purpose of the article.Electrolysis was conducted in the potential range from -1050 to -1250 mV relative to the silver chloride electrode (AgCl/Ag) in the presence of a background sodium sulphate solution (0.5 M of Na2SO4 solution) containing 0.005, 0.0125, and 0.025 M ZnSO4 with the introduction of high-molecular surfactants: cationic and anionic coagulants (flocculants) and foaming agents (lignosulphonate – LSTP).During the electrolysis in a background solution of sodium sulphate with stirring, it was found that the process of discharge of zinc ions on a solid electrode occurs in a mixed-kinetic mode. It was shown that positively charged additives, such as lignosulphonate and cationic coagulant (flocculant) Besfloc K6645, have a negative effect on the dynamics of zinc cation discharge, while negatively charged Besfloc K4034 has practically no effect. The approach proposed in this work allows evaluating the influence of additions of cationic and anionic surfactants on the stage of zinc discharge on a solid electrode, which was the practical and scientific value of this work

Evaluation of natural flocculant efficiency in the harvest of microalgae Monoraphidium contortum

This study assesses two parameters that can result in high efficiency in the recovery of the microalgae Monoraphidium contortum. The significant contribution of this paper is to test different coagulants in different conditions of concentration in the coagulation and flocculation processes followed by sedimentation to evidence the best coagulant and the best condition for harvesting of Monoraphidium contortum biomass. So the proposed methodology aimed to perform preliminary tests using a tannin-based cationic coagulant (TANFLOC SG®), FeCl2, and Al2 (SO4)3, where they were performed at concentrations of 0, 20, 40, 60, 80, and 100 mg L−1 at a fast mixing speed of 400 RPM. The tests determined 20 mg L−1 of Tanfloc SG® as the most efficient turbidity reduction in the preliminary test. The obtained results were used to construct a non-factorial central composite planning. Therefore, after a design of experiments, the study outcome shows the best turbidity removal range from the main tests came at 35 mg L−1 and 550 RPM of fast mixing speed.

Understanding the zinc discharge from sodium sulphate solution in the presence of surfactants

This paper aims to understand the effect of surfactants on zinc discharge in sulphate solutions on a solid electrode and to collect new experimental data that would give a deeper insight into the processes involved in industrial electrolysis. Anionic and cationic coagulants (flocculants) and an anionic frother were used as surfactants. Electrolysis was conducted in the potential region of –1050 to –1250 mV (Ag/АgCl) in stationary and dynamic conditions in sodium sulphate solution under intensive stirring. The authors obtained comparative data on the zinc discharge current in electrolyte with and without frother at the scan velocities of 2 to 100 mV/sec. It is noted that at higher scan velocities (&gt;10–20 mV/sec) and in the initial electrolysis phase the zinc discharge process develops in a mixed mode. In this case, as the study showed, the positive effect of the frother on zinc discharge is most distinguished. A reaction order was designed based on zinc ion with four potentials to prove that the zinc electrowinning process develops in a mixed mode. It is shown that the addition of frother raises the reaction order from 1.2 to 1.5, which is attributed to a larger effective cathode surface area. The data obtained in a galvanostatic mode under intensive stirring conditions indicate that, at the current density of 1.7 mA/cm2, the electrode polarization is 1.6 times lower in the presence of cationic coagulant and almost 3 times lower in the presence of anionic coagulant. The data given in this paper are also indicative of a changing electrolysis mode. Under stirring, a transition is observed from a diffusion mode of zinc ion reduction to a mixed one. The experimental data obtained under intensive stirring conditions in sodium sulphate solution with frother, as well as anionic and cationic coagulants are in line with the theory of electrochemical processes.

Examining metal migration through geotextiles during dewatering

This paper presents a study conducted to assess the influence that a filter cake deposited on the surface of the geotextile has on the mobility of three metals (Cu, Pb, Zn) during filtration of a contaminated sediment. Two chemical additives (cationic coagulant and cationic polymer) were introduced to the sediment to increase the particle size and improve the filtration efficiency. Bench scale experimentation was conducted to identify contaminant reduction using a small volume of sediment. A field test was applied to observe what effect three-dimensional filtration and a larger filter cake had on metal mobility. Analysis of the effluent was conducted to determine total and dissolved metal contaminants, as well as particulate matter. Effluent chemical properties (pH, Eh, and zeta potential) were analyzed to identify a possible rationale for variations in concentration during filtration. The results of the study show that as an increasing buildup of filter cake on the surface of a geotextile developed, filtrate quality was improved with respect to the metal and particulate contaminants considered. In addition, the metals detected in the effluent were primarily in the solid state, suggesting further reduction could be achieved through subsequent filtration (if desired).