Papers by Keyword: Coagulation

Abstract: This research demonstrates the production of membranes utilizing polyethersulfone (PES). Cellulose Acetate (CA) at 5% and Polyethylene Glycol (PEG) at 5% are incorporated into the PES membrane as additives, while ethanol serves as a variable non-solvent in the coagulation bath. The incorporation of CA and PEG additives serves to enhance the performance and characteristics of PES membranes. Fabrication of PES membranes utilizing the non-solvent induced phase separation (NIPS) technique. The impact of additive incorporation was assessed through various characterization tests, including Swelling degree, Tensile strength, contact angle, Scanning Electron Microscopy (SEM), and Fourier transform infrared (FTIR). The results indicated that the swelling degree value increased from 13.66% (PES) to 39.40% with the addition of PEG and CA. Nevertheless, the membrane's mechanical strength was diminished as a result of the inclusion of PEG. PES/CA exhibits the highest tensile strength value at 1.8 MPa, while PES/PEG has a peak of 1.4 MPa. The optimal contact angle measurement was achieved on the PES/CA/PEG membrane at 50°. The SEM characterization results indicated an increase in membrane pore size, with the modified membrane exhibiting a pore size range of 0.331-0.664 μm. The incorporation of 60% ethanol as a non-solvent resulted in the maximum swelling degree value of 41.05%. In conclusion, the characteristics of the membrane are influenced by the combination of additive Cellulose Acetate (CA) and Polyethylene Glycol (PEG) through blending.

Abstract: The article deals with the peculiarities of the process of clay particle aggregation when coagulant and flocculant are introduced, as well as the regularity of formation and deposition of the formed flocs. The studies were carried out on a model suspension of bentonite clay with a concentration of 1-10 g/l. In the course of the study, the regularities of aggregate formation in the process of coagulation; the combined action of coagulants and flocculants, as well as the destruction of flocs under the influence of mechanical action were determined, and theoretical ideas were formed regarding the models of the process and the structure of the formed aggregates. It was found that the aggregation of fine particles has optimal ratios of both the concentration of the solid phase and the ratio of flocculant to the solid phase, at which the maximum rate of particle settling is observed. The optimum concentration for this type of clay, at which the maximum flocculation rate is observed, was 4-6 g/l. At other optimum concentrations, a slowdown in floc settling is observed due to the lack of formation of a spherical structure at low concentrations and compressed settling at higher concentrations. To intensify the sedimentation of loose flocs, it was proposed to introduce additional mineral lime particles with a particle size of 20-40 μm, which increase the weight of flocs and accelerate their sedimentation.

Abstract: Textile products remain one of the basic products the human being cannot do without. Textile manufacturing industry is an important source point of waste water as the production of textiles requires large amount of water and over 90% of the water is discharged as waste. Due to the fact that textile products are produced in varieties of colours and patterns, use of dyes and other chemicals are usually unavoidable. consequently, effluents from the manufacturing process contain a quite number of organic and inorganic chemical compounds that have been found to have hazardous impacts on the environment. Coagulation and adsorption processes are important parts conventional waste water treatment methods. The cost of acquiring chemical coagulants and activated adsorbent has triggered research towards low cost alternatives with eco-friendly properties. In this paper, the use of natural coagulants and adsorbents for treatment of textile wastewater is looked into to cover various types of the natural materials employed for the abatement of various pollutants from the industrial effluent. The principle of adsorption and coagulations, methods used in the preparation of the natural coagulants and adsorbents and their application to real textile wastewater-this covers the review of reported works in the recent decade and the latest trend in the treatment textile waste water in such a way that environmental protection and human health are prioritized as textile waste water is known for its toxic constituents. In addition, the survey reveals the research gap in the area of application of nature based materials to industrial textile waste water which may be of importance for intending researchers in natural coagulation and adsorption.

Abstract: Enhanced treatment of river water was investigated by the modified coagulation-flocculation process for the application of self-cleaning filters (SCF’s) in the removal of turbidity using a combination of Alum and Sudfloc 3880. This study is aimed to improve the removal of iron and turbidity concentrations from river water and reduce water loss. This is achieved by piloting innovative water treatment technologies such as the SCF’s Plant. The new technology further assessed the effectiveness, efficiency, and operability of the SCF’s Plant by varying certain operational parameters such as water flow, differential pressures, coagulant, and flocculent dosages. The results established in this study critically analyze the feasibility of deploying water treatment technologies such as the SCF Plant in areas with similar environmental conditions and/or facing similar water treatment challenges. The removal efficiencies of turbidity were about 40 % and further optimization will be continued until 90 % to 100 % is achieved. The average removal efficiency of turbidity was 40 % and achieved at a 250 m³/h flow rate. The average removal across all flow rates was over 20 %. Further optimization of the RF14 will be carried out using other chemical combinations and formulations at various process settings while bypassing the PLF filters. The PLF elements will be brought into service to further reduce the turbidity after the optimization of the RF14. Keywords: Water, Treatment, Coagulation, Flocculation, Processes, Technologies, Filters ^*

Abstract: Selective laser melting (SLM) is a manufacturing technology of metal parts of any shapes with target mechanical properties by means of laser melting. This paper discusses the effect of SLM parameters: laser output power, laser movement velocity, scanning pitch and preheating temperature of a powdered material on surface formation mechanism, namely, its physical configuration when melting cobalt-chromium-molybdenum powdered material Со28Cr3Mo. The study points at structural differences of melted surfaces even under identical process parameters. Several types of surface formation are identified, e.g. homogenous melt, coagulated particles, and shapeless particles. Vapor pressure, Marangoni effect, and heat effect of a melted powder are stated to be key reasons for rough surface. This research is of high importance for understanding the effect of SLM parameters on formation of a target quality surface, positive stability and repeatable accuracy of the process.

Abstract: This paper analyzes the effect of SLM parameters on mechanical characteristics and surface roughness of a single-component copper powder. The study reports on appropriate SLM conditions for a single-component copper powder; to form a layer a technique within layer-by-layer selective laser melting is suggested and comprises roughing, semi-finishing and finishing modes. The work establishes a range to vary surface roughness, porosity and ultimate compressive strength of a single-component copper powder by means of laser processing conditions. Rz is variable 332 to 689 μm, porosity ranges approximately 13-39%, and ultimate compressive strength is 8 to 104 МPа.

Abstract: In order to ensure the efficient separation of solid particles in heavy oil sewage by air flotation technology, in this paper, the flotation performance and mechanism of coagulated particles are studied in terms of contact angle, light transmittance and Zeta potential by changing pH, inorganic flocculants, organic flocculants and reagent dosage in the process of flotation. The results show that stage of air flotation could be benefited by increasing light transmittance, zeta potential of sewage, and contact angle of coagulated particles during the coagulation stage. When pH of sewage is 6.5, dosage of PAC and anionic PAM (molecular weight: 10 million) is 150 mg/L and 0.5 mg/L, respectively, an optimum coagulation effect as well as the treatment effect could be achieved.

Abstract: Effluents from pulp and paper mill typically consist of high loading of inorganics compounds (e.g., Na₂CO₃, Na₂S, NaOH and NaCl) and organics compounds (e.g., lignin and polysaccharides fragments, alcohols, carboxylic acids) Several methods, such as biological, physical and chemical treatment, have been reported to degrade these molecules. However, coagulation is by far the cheapest, simplest and most common method employed for secondary wastewater treatment to reduce colour and organics. In this research, two most widely used methods were employed to treat a model wastewater of pulp and paper industry, namely a combination of coagulation-flocculation-UV irradiation/H₂O₂ and electrocoagulation (EC). In the application of coagulation-flocculation-UV irradiation/H₂O₂ method, the decrease in colour (measured as absorbance at 500 nm) was 71%, and the COD removal was measured to be 38% under the optimum conditions of pH 8, coagulant dose of 700 ppm, flocculant dose of 60 ppm, 130 rpm of coagulant stirring rate, 1 day irradiation time, and 25 mM of H₂O₂. For the EC method, 91% reduction of color and 84% reduction of COD were achieved at 40 min of electrolysis time, pH of 8, 600 ppm of NaCl concentration, electrode distance of 1.5 cm and 2 V of voltage. The EC method may serve as an efficient method for color and organics removals from pulp and paper mill wastewater.

Abstract: Polyamidine (PA) is a novel high cation coagulant aid for water treatment. In the present study the structure, coagulation ability and floc characteristics (including coagulation kinetics, floc dimension, floc strength and floc recover ability) were discussed. As a dual-coagulation, polyamidine was combined with AlCl₃ and PAC to remove dispersed yellow from wastewater. The results showed that the polyamidine exhibited higher intrinsic viscosity and higher charge neutralization ability than cationic polyacrylamide (PAM). Atomic force microscopic (AFM) and transmission electronic microscopic (TEM) images showed a dendritic, stretched structure of PA. The dosage of PAC/PA and AlCl₃/PA and pH were investigated and optimized. Under the optimum condition, the color removal efficiency reached 96% as the concentration of 14/0.2 mg/L for AlCl₃/PA (PA was combined with AlCl₃) at pH 6. Meanwhile, the highest decoloring efficiency (97%) was achieved in the process when PAC/PA (PA was combined with PAC) dosage was 18/0.6 mg/L at pH 6.0-8.0. The addition of polyamidine could improve the color removal efficiency, including increasing the zeta potential evidently and reducing the aluminum coagulants dosage as well. Compared with AlCl₃/PA, PAC/PA which contained higher polymeric aluminum, exhibited a better coagulation ability to adapt a wide range of pH. However, when PAC/PA and AlCl₃/PA expressed the same removal efficiency, AlCl₃/PA showed a less coagulant dosage in raw dye wastewater pH. With PA dosages increased, the floc of AlCl₃/PA showed a gradually adding strength and recovery ability, but in PAC/PA system the tendency was unclear. In PAC/PA system, PA dosage increase only improved floc density.

Abstract: Skim natural rubber (NR)–clay nanocomposites were prepared by a coagulation method using the organoclays Cloisite 15A, Cloisite 20A and Cloisite 30B. This work investigated the use of bagasse fiber developed from locally sourced and renewable material as an alternative and/or secondary filler in skim NR–clay nanocomposites. Bagasse fiber loading in the nanocomposites was 0, 5, 10 and 20 phr; the effects of fiber content on cure characteristics and mechanical properties were then determined. The results suggest that the Mooney viscosity tended to increase with increasing fiber content, whereas the cure time at 90% and fatigue testing score decreased as fiber loading increased.