Amount Of Sodium Hydroxide Research Articles

Alkali Activation of Metakaolin and Wollastonite: Reducing Sodium Hydroxide Use and Enhancing Gel Formation through Carbonation

Alkali activated materials (AAMs) offer significant advantages over traditional materials like Portland cement, but require the use of strong alkaline solutions, which can have negative environmental impacts. This study investigates the synthesis of AAMs using metakaolin and wollastonite, aiming to reduce environmental impact by eliminating sodium silicate and using only sodium hydroxide as an activator. The hypothesis is that wollastonite can provide the necessary silicon for the reaction, with calcium from wollastonite potentially balancing the negative charges usually countered by sodium in the alkaline solution. This study compares raw and carbonated wollastonite (AAM-W and AAM-CW) systems, with raw materials carefully characterized and binding networks analyzed using TGA, FT-IR, and XRD. The results show that while wollastonite can reduce the amount of sodium hydroxide needed, this reduction cannot exceed 50%, as higher substitution levels lead to an insufficiently alkaline environment for the reactions. The carbonation of wollastonite enhances the availability of silicon and calcium, promoting the formation of both N-A-S-H and C-A-S-H gels.

Preparation of solid alkali activator for geopolymer synthesis using vanadium-bearing shale tailing

The vanadium-bearing shale tailing (VST) with large reserves pollutes the environment and urgently needs to be utilized as a resource. Due to its main component being silica, VST has great potential as a raw material for geopolymer. Therefore, this study uses VST to prepare the solid alkali activator (SAA) by thermochemical methods. Analysis show that the temperature and NaOH dosage of thermochemical reaction significantly affect the alkaline activation effect of SAA. Temperature affects the silicate content and the amount of NaOH affects the soluble silicate content in SAA. When the reaction temperature is high (such as above 900 ℃) and the amount of sodium hydroxide is low (such as the mass ratio of sodium hydroxide to VST is 0.6), quartz almost transforms into silicates, but the silicates have a stable cyclic chemical structure and are difficult to dissolve during the geopolymerization reaction. When the reaction temperature is low (such as less than 700 ℃) and the amount of sodium hydroxide is high (such as the mass ratio of sodium hydroxide to VST is 0.9), quartz in VST is difficult to fully convert into silicates, there are unreacted quartz and sodium hydroxide in SAA, and SAA has poor alkaline activation performance. The optimal synthesis process conditions for SAA are as follows: synthesis temperature is 900 °C and the mass ratio of sodium hydroxide to VST is 0.95. The main silicate components of SAA are Na2SiO3 and Na15.6Ca3.8Si12O36. During the synthesis of one-part geopolymer (OPG), Na2SiO3 dissolution generates a strong alkaline reaction environment and provides active silicon-oxygen tetrahedron monomers or oligomers, Na15.6Ca3.8Si12O36 is bonded with geopolymer gel structure by stable cyclic silicate structure, which makes OPG have a compact integrated structure. When the mass ratio of SAA to MK is 1:1.3, the 7-day compressive strength of the prepared OPG is about 49 MPa, SAA has the potential as a substitute for commercial sodium silicate to prepare geopolymers.

An eco-friendly enzymatic treatment to prepare spinnable banana fibers as an alternative to cotton for textile applications

Banana fibers are a sustainable material with natural mechanical strength and antibacterial properties. These fibers are extracted from the large amount of waste produced by banana pseudo stems annually. However, despite their numerous advantages, their stiffness and rough texture impede their full use in the textile. This research investigates the degumming treatment of banana fibers using enzyme combination and chemical methods to achieve spinnable soft banana fibers. An L9 orthogonal array was used in a Taguchi design of the experiment to optimize the process parameters. For enzyme combination degumming, the experimental setup comprised different quantities of hemicellulase, laccase, amylase, and pectinase; for chemical degumming, varied amounts of sodium hydroxide (NaOH) were used. The results indicate that enzyme-based degumming procedures produce better results than chemical treatments. Optimum enzyme combinations for various fiber qualities were found using the Taguchi design of experiments. These combinations included Hemicellulase 5 %, Laccase 5 %, Amylase 3 %, and Hemicellulase 5 %, Laccase 3 %, Pectinase 5 %. Without degrading the cellulose structure, these ideal enzyme combinations produced fibers with lower lignin content and higher cellulose percentages, moisture content, and tenacity values. By determining the most efficient enzyme combinations and their effects on fiber qualities, the study offers sustainable fiber processing methods for textile grade banana fiber.

Boosting methanolysis of polycarbonate (PC) for bisphenol A recovery from end-of-life PC and PC/ABS blend

Poly(bisphenol A carbonate) (PC) is an essential polymer from fossil sources. Currently, PC lacks any economically viable recycling strategy, which leads to a loss of valuable resources, and the accumulation of PC in the environment can have a negative impact on human health due to the leaching of toxic Bisphenol A (BPA). BPA recovery from PC wastes is a prerequisite to meet the demand for sustainable resource utilization and address environmental concerns. Hence, this work demonstrates the efficient BPA recovery from PC wastes via methanolysis at high PC loading (47 wt%) in the presence of a low amount of sodium hydroxide (NaOH, ≤0.05 wt%) at moderate temperatures (125 °C – 175 °C). Selected conditions prevented unwanted decomposition of BPA and ensured a mild alkaline product requiring simple purification steps to recover BPA. The environmental impact factor (ξ) of these processes was shown to be quite low compared to the ones represented in the literature. When these processes were used to recover BPA from real wastes: 93 ± 1.5 % of pure BPA was recovered from end-of-life PC roof panels (EOL-PC) after 30 min at 175 °C with 0.004 wt% of NaOH. On the other hand, direct recovery of BPA from the EOL-PC/acrylonitrile butadiene styrene (EOL-PC/ABS) blend was hindered by additive contamination and proceeded at a slower reaction rate due to the presence of ABS. However, subjecting EOL-PC/ABS to a decolorization-depolymerization method ensured ∼94 ± 2.5 % BPA yield.

Controlled synthesis and tuned fluorescence properties of NaGdF4:Yb, Er up-conversion nanocrystals through one-step hydrothermal approach

The properties of NaGdF4:Yb, Er nanomaterials tuned by synthesis conditions have always been one of the research hotspots in the field of upconversion nanomaterials. In this work, NaGdF4:Yb, Er upconversion nanomaterials capped with oleic acid (OA) molecules were prepared by one-step hydrothermal method. Controlling the fluorescence properties of NaGdF4:Yb, Er nanomaterials by changing the synthesis conditions were principally investigated. The results showed that the crystalline state of the as-prepared upconversion nanomaterials tended to be intact and fluorescence emission capability enhanced when the reaction temperature increased from 140 °C to 160 °C, 180 °C and the reaction time extended from 6 h to 18 h. From 0.00 mmol to 0.75, 2.25, 5.00, 8.75, 12.50, 17.50 mmol of sodium hydroxide amount, the synthesized upconversion nanoparticles (UCNPs) transferred from orthorhombic GdF3 to hexagonal β-NaGdF4. And when the amount of sodium hydroxide was 2.25 mmol, the as-prepared nanoparticles exhibited stronger luminescence intensity. The ratio of Re3+ (Gd3+:Yb3+:Er3+) could also affect the properties of the as-prepared UCNPs. The nanomaterials emitted relatively stronger fluorescence when the ratio among Gd3+, Yb3+, Er3+ was 78:20:2. This work provides solid foundation for further theoretical study and practical application of NaGdF4:Yb, Er nanomaterials.

Sodium Carbonate Pulping of Wheat Straw—An Alternative Fiber Source for Various Paper Applications

European paper mills are currently facing the question of whether recovered paper, their main raw material, will be available in sufficient quantities and an acceptable quality in the future. An alternative to recovered paper or wood fiber is the use of agricultural residues such as wheat straw. Sodium carbonate-based straw pulping processes have the advantage of not requiring recausticizing for chemical recovery, which reduces investment and operating costs. With the addition of oxygen, delignification can be significantly improved to provide pulps suitable for bleaching. This study compares the pulping of wheat straw using sodium carbonate, sodium carbonate + oxygen, and sodium carbonate + sodium hydroxide + oxygen. Pulping parameters such as temperature, retention time, and chemical charge were varied, and their influence on pulp properties was studied. The use of sodium carbonate alone produced pulps with high yields of up to 72% and comparably high burst and compressive strength. The addition of oxygen and small amounts of sodium hydroxide produced pulps with a high initial brightness of 42 %ISO and a low kappa number (18), still at high pulp yields of 62%. These pulps were two-stage bleached to achieve brightness levels of up to 73 %ISO.

Self-assembly of hierarchical ZSM-5 particles on rice husk template as hybrid catalysts for boosting methanol aromatization

Herein, natural rice husks with hierarchically porous structures were used as a platform to assemble ZSM-5 particles (denoted as hierarchical ZSM-5) to improve diffusion properties in the methanol-to-aromatics (MTA) reactions. Rice husk could work as the platform to immobilize zeolite grains and provide additional silicon sources for the growth of zeolite particles. Sodium hydroxide amount and SiO2/Al2O3 ratio strongly determined the acid properties, and the rotational crystallization condition favored the zeolite formation. Improved diffusion properties of hierarchical ZSM-5 particles were confirmed by comprehensive pore analysis and benzene diffusion experiments, showing an excellent diffusion property towards aromatic molecules. Compared with commercial microporous zeolite in the catalytic MTA reaction, hierarchical ZSM-5 exhibited superior aromatics selectivity (40.8 vs. 35.8 %), higher liquid hydrocarbon yield (22.3 vs. 14.7 wt%), and longer lifetime (60 vs. 40 h). These results offer new insights into the controllable synthesis of Hier-ZSM-5 with a hierarchically porous structure using biomass as templates.

Catalytic activation of peroxodisulfate using shape-controlled cerium-manganese composite oxide for phenol degradation: Kinetics and degradation pathway investigation

Phenol-containing wastewater is typical organic wastewater, and its treatment is arduous. An advanced method to treat this type of wastewater is persulfate activation. Environmentally friendly cerium-manganese composite oxide materials were synthesized by hydrothermal method and applied to the phenol degradation process. Various ratios of cerium and manganese, as well as the amount of sodium hydroxide, were investigated. The solid solutions of cerium and manganese were formed and confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). H2-temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS) were utilized to analyze the synergistic effect of cerium and manganese. It is found that there is a transformation between Ce4+/Ce3+ and Mn2+/Mn3+, which makes the material more trivalent manganese and thereby increases the catalytic activity. The effect of materials in catalyzing phenol degradation by peroxodisulfate (PDS) under various preparation conditions is discussed and high-efficiency removal of phenol can be achieved and the removal rate at 180 min is close to 100%. The kinetic of this process was investigated and activation energy of phenol degradation is 62.35 kJ/mol. The degradation pathway of phenol was studied and it is found that PDS can be activated by low metal ions and the ·OH and SO4·– radicals play crucial roles according to the quenching experiments.

Technological suitability and improvement for shaping environmental performance: A life cycle perspective on Fenton-based wastewater treatment processes

Water resource management and wastewater treatment are designed to ensure a safe and clean water resource in the pursuit of sustainable development goals. Chemical-based wastewater treatment processes typically involve significant consumption of resources, by means of chemical or material uses, which potentially lead to significant environmental impacts. This study intends to gain a comprehensive understanding of the environmental impacts associated with two Fenton-based wastewater treatment processes, namely, fluidized-bed reactor (FBR-Fenton) and conventional Fenton (C-Fenton) methods, for four industrial wastewater tests (organic wastewater from pulp mill, pharmaceutical, oil-containing, and polyethylene terephthalate (PET) rinsing), from a technical suitability perspective. The present study adopts ISO 14040 guidelines for life cycle assessment (LCA) and uses the IPCC and ReCiPe methods for environmental impact assessment. The results show that the FBR process has relatively lower environmental impacts than the C-Fenton process according to the IPCC and ReCiPe impact results, partly due to differences in chemical usage and electricity consumption. The results obtained from the IPCC method show that the C-Fenton process had a relatively higher impact on global warming potential than the FBR process, with impacts in the range of 20.5–141.9 kg CO2eq/1 kg COD and 12.0–41.9 kg CO2eq/1 kg COD, respectively, mainly due to variations in the amount of sodium hydroxide or sulfuric acid required to achieve the desired degree of water quality from different raw industrial wastewater sources. Furthermore, the reduction in the use of high-impact chemicals contributes to remarkable environmental benefits for the processes, while process adjustment may not guarantee environmental benefits. This result implies that the environmental performance of Fenton-based processes significantly varies depending on the treatment of raw wastewater characteristics; that is, the environmental advantage of a wastewater treatment technique strongly depends on the determination of a suitable process. This information can be used to support the determination and advancement of future wastewater treatment technologies aimed at improving environmental outcomes.

Synthesis of a loess-based 4A molecular sieve and its application performance in detergents

Herein, activated loess was obtained via acidification and alkalisation and was mixed with sodium hydroxide, water and aluminium sulphate to prepare a loess-based 4A molecular sieve using the hydrothermal conversion method. The sieve performance was characterised, and the effect of raw materials and reaction conditions on the sieve was investigated. Results showed that it exhibits different microstructures according to its crystallinity and impurity content. Moreover, the amount of sodium hydroxide and the reaction temperature had a substantial influence on its synthesis, while water and the reaction time exhibited less influence. The synthesis method was optimal when the reaction temperature was 90 °C, reaction time was 4 h, pH was ∼ 13 and the mixture ratio was SiO2:Al2O3:H2O:NaOH = 1.9:1:213:12. Finally, the application performance of the molecular sieve in detergents was studied. The sieve showed complete adherence to the National Standard of Detergent in China (GB/T 1767–2003).

A comparative study of prediction models for alkali-activated materials to promote quick and economical adaptability in the building sector

Alkali-activated materials (AAMs) have recently gained attention as potentially useful alternative binders that can reduce carbon dioxide emissions initiated by the production of Portland cement (PC) and decarbonize concrete production. Plenty of research has been conducted to explore the numerous characteristics of AAMs. However, when utilizing typical empirical and statistical methods, it is still difficult to accurately estimate the mechanical features of AAMs due to inaccuracy and uncertainty. This research presents machine learning (ML) models intending to estimate AAM's compressive strength (CS) based on their mixture's proportions. Literature records weremined to compile a comprehensive dataset with 676 mixture designs. Three ML models were employed to assess AAM's CS prediction capabilities. These models included an artificial neural network (ANN), a K-nearest neighbor (KNN), and a decision tree (DT). In addition, RreliefF and interaction analysis were conducted to examine the significance and interaction of various factors used in the database. Statistical assessments of results showed that ANN's prediction accuracy was higher than that of KNN and DT. The correlation coefficient (R2) values of 0.91 for ANN, 0.79 for KNN, and 0.78 for DT confirm the applicability of ANN for determining the CS of AAMs. RreliefF analysis showed that the most important variables were the amounts of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3), followed by the fine aggregate, water/binder ratio, specimen age, and slag. The remaining variables moderately affected the results (i.e., CS of AAM). ML approaches can evaluate AAM CS across different input parameter values to optimize resource allocation and streamline future testing. The RreliefF analysis and interaction study indicated how input components affect AAM CS. These findings may help researchers and industry professionals determine the best raw material quantity, composition, and other factors for AAM development.

EXTRACTION AND CHARACTERIZATION OF NATURAL CELLULOSE FIBERS FROM REED STRAW: MORPHOLOGICAL, MICROSTRUCTURAL AND THERMAL PROPERTIES

As an available resource rich in cellulose, agricultural residues have attracted a lot of interest for textile and other applications. Herein, reed straw fiber was obtained from a typical agricultural waste – reed straw – by an alkali-oxygen one-bath process. The effects of the amount of sodium hydroxide and hydrogen peroxide, the treatment temperature and time on the degumming rate were discussed. The optimum technological parameters of the alkali-oxygen one-bath process were found as follows: the dosage of sodium hydroxide was 35 g/L, the dosage of hydrogen peroxide – 30 mL/L, treatment temperature – 85 °C and cooking time – 2 h. Under these conditions, the degumming rate achieved was 54.30%. The prepared fiber will be considered as a promising and sustainable raw material for the textile industry and other applications.

Bond strength characteristics of high strength alkali activated slag concrete mixes

Bond characteristics are influenced by several factors such as concrete compressive strength, type, diameter, and embedment length of the bar and confinement of concrete. Herein, an attempt has been made to evaluate the bond strength characteristics of a new class of high-strength, flowable, alkali activated slag concrete mixes made using the industrial by-products from iron and steel industries. Such evaluations are made using the results of direct pull out tests where again, the bond stress – slip behaviour of the trial mixes at different ages are also studied. GGBFS was used as the principal binder along with fine amorphous quartz powder in the development of the present class of high strength, flowable AASC mixes. While mixtures of steel slag sand and quartz sand were used as the fine aggregates, 12.5 mm down electric-arc furnace slag aggregates constituted the coarse aggregate fractions in all these mixes. The alkaline solutions used consisted of mixtures of specified amounts of sodium hydroxide flakes dissolved in the calculated quantity of water pre-mixed with the liquid sodium silicate solution. The experimental study was planned based on Taguchi’s design of experiments methodology. A set of AASC mixes were developed and evaluated for their workability characteristics along with compressive strengths at the ages of 3, 28, 56 and 90 days. Bond strength characteristics of a set of nine of such mixes were evaluated in an initial calibration phase. Strength prediction equations were then derived based on those initial results, the predictive capability of which were then assessed and ascertained with actual results of experiments on a set of six new mixes, in the prediction phase. Further better bond stress-slip behavior, with higher bond strength values, varying in the range of 12–14 MPa as compared to control OPC based reference concrete mix were obtained for the AASC mixes.

Effect of pH of the precursor solution on the photocatalytic and biomedical applications of enzyme coupled ZnO and SnO2 nanomaterials: A comparative study

The focus of this study is to investigate the effects of pH of the precursor solution and the addition of vermiwash on the photocatalytic and certain biomedical applications of zinc oxide (ZnO) and tin oxide (SnO2) nanopowders prepared via co-precipitation method. The pH of the starting solution was varied as 8, 9 and 10 through the addition of suitable amount of sodium hydroxide (NaOH) and vermiwash. These vermiwash-derived enzymes activated ZnO and SnO2 nanopowders (prepared at different pH values) were applied for biomedical applications viz. antibacterial, antioxidant and antidiabetic activity for the first time. The prepared samples were also characterized using various analytical techniques viz. XRD, SEM, TEM, EDS, FTIR, XPS, BET, and UV-vis spectra. The results of these analytical studies are correlated with their photocatalytic degradation abilities and also biological applications. The photocatalytic activity of the nanoparticle were analyzed using a visible annular type photo reactor by degrading methylene Blue (MB) - a standard cationic dye - under UV-visible irradiation. A remarkable dye degradation efficiency of 98% and 94% were achieved for the best samples of vermiwash activated ZnO and SnO2 (prepared from starting solution with pH 9), respectively. The lower band gap values (2.97 and 3.1 eV) of these samples as calculated from Tauc's plots and their enhanced surface area as observed from the BET analysis play crucial roles in improving their photocatalytic efficiency. Remarkable antibacterial, antioxidant and antidiabetic activities were also recorded for the samples prepared at pH 9.

In situ synthesis of ferrate based on calcium hypochlorite for organic matter removal

Ferrate is a promising environment-friendly water-treatment agent due to its multiple function. However, its large-scale application in sewage treatment is limited because of its instability in aqueous solution and the high cost of pure ferrate. This study demonstrated an improved wet oxidation process for synthesising ferrate by oxidising ferric with calcium hypochlorite (Ca(ClO)2). The effects of reagent dosage and temperature on ferrate (VI) were investigated. The optimum conditions for ferrate (VI) synthesis was obtained (1 g of calcium hypochlorite, 5 g of sodium hydroxide (NaOH) and 4 g of iron (III) chloride (FeCl3) in 25 ml of water at 20°C and stirring for 30 min). Under the optimum conditions, the available chlorine and sodium hydroxide amount was about one-fifth and one-half of that of traditional sodium hypochlorite oxidation, respectively. The product was characterised by ultraviolet–visible spectroscopy and X-ray photoelectron spectroscopy. It was concluded that ferrate was present in the generated ferrate solution. Low-temperature, airtight and shading conditions and the addition of sodium silicate are conducive to the preservation of fresh ferrate. At pH 5.0, fresh ferrate could effectively remove methylene blue (MB) and chlorpyrifos in water, and the average removal rate of MB or chlorpyrifos was about 55% higher than that by pure ferrate.

Accelerating the reaction process of sodium carbonate-activated slag mixtures with the incorporation of a small addition of sodium hydroxide/sodium silicate

This paper investigates the possibility of accelerating the slowly progressive early reaction process of sodium carbonate-activated slag mixtures by adding a small amount of sodium hydroxide or sodium silicate to the sodium carbonate activator. The reaction process of sodium carbonate-activated slag mixtures was evaluated by isothermal calorimetry and ultrasonic wave technology. Test results showed that adding a small amount of sodium hydroxide or sodium silicate to the sodium carbonate activator significantly accelerated the reaction process, resulting in shortened setting times and enhanced mechanical properties. Only 1% Na2O contribution from sodium hydroxide addition can lead to a 2-d compressive strength of 20 MPa for sodium carbonate-activated slag mixtures. In addition, the 28 days compressive strength was significantly higher than the sole sodium carbonate activator. The addition of sodium hydroxide or sodium silicate also considerably influenced the rheological behavior of the sodium carbonate-activated slag mixture, enhancing the structural build-up rate and transforming the shear-thinning behavior to Bingham or shear-thickening behavior. A more well-packed microstructure was observed in the mixtures with the addition of sodium hydroxide; however, more micro-cracks were observed in the mixtures with a small incorporation of sodium silicate.

Modeling and prediction of biodiesel production by using different artificial intelligence methods: Multi-layer perceptron (MLP), Gradient boosting (GB), and Gaussian process regression (GPR)

In this study, different distinct approaches of machine learning (ML) including Multi-layer perceptron (MLP), Gradient Boosting with DT (GBDT), and Gaussian process regression (GPR) were employed in order to predict the amount of Papaya oil methyl ester (POME) biodiesel production. To optimize the POME production, yield of these models were optimized with focus on maintaining generality and enhancing the prediction accuracy. The influencing transesterification factors on the biodiesel manufacture like the temperature of reaction (℃), amount of sodium hydroxide as catalyst (wt.%), treatment time (min), and methanol to papaya oil molar ratio were chosen as the inputs. NaOH was employed as a catalyst at the phase boundary for the reaction between papaya oil and short chain alcohols. Considering the MAPE criterion, the MLP, GBDT and GPR models have shown the error rates of 8.9670E-02, 2.0324E-01 and 7.2080E-02, respectively. Similarly, the GPR process gets the best R2 criterion score of 0.996, followed by GBDT with 0.989 and MLP with 0.971. The Mean Absolute Error (MAE) also shows the best model is the Gaussian process, which has an error rate of 4.7. In addition, the optimal POME yield production value was estimated through the proposed method to be about 99.96%, in the optimized values of 64 ℃, 0.875 wt%, 7.375 min, and 10.875 for the temperature reaction (℃), amount of catalyst, treatment time, and methanol to papaya oil molar ratio, respectively.

Evaluation of Strength In Fly Ash Based Geo polymer Concrete

Construction materials that are friendly to the environment are now being researched and developed all over the globe in an effort to limit the use of natural resources that are depleting at an alarming rate and to cut down on the production of greenhouse gases. In this respect, geopolymer plays an extremely important function, and a large number of researchers have investigated the numerous dimensions of its viability as a material for binding. In order to alter the geopolymerisation reaction of fly ash, ground granulated blast furnace slag (abbreviated as GGBS) has been used into fly ash-based geopolymer concrete (abbreviated as GPC). In this paper, the influence of various proportions of GGBS (0-100%) on Fly Ash based GPC, as well as the effect of the amount of Alkaline Activated Solution (AAS) in the mixture of GPC, is studied to determine how it affects the compressive strength of the GPC under conditions of ambient temperature. It was observed from the results of the experiments that the compressive strength of the GPC increases both with an increase in the percentage of GGBS and also with an increase in the amount of the sodium silicate solution in which the concentration of sodium hydroxide in the aqueous solution is fixed at a constant value of 10M. This was the case even though the amount of sodium hydroxide that was present in the solution remained the same.

Photodegradation of Methylene Blue Using Carbon-Doped ZnSn(OH)6 Composite Coated on Membrane

The dye contamination of water is a global concern in the environment. In this study, the photocatalytic technology and membrane module were combined to improve the surface distribution of the active species of the catalyst for better degradation of the methylene blue (MB) dye under visible light. ZnSn(OH)6 was chosen due to carbon’s complex metal oxide doped to facilitate the application under visible light. The numerous characterizations were analyzed in the composites to verify the consistency of the optimum degradation of MB over the catalyst coated on the membrane. During the preparation of the ZnSn(OH)6 composite, the results confirmed that different reaction times and amounts of sodium hydroxide significantly affected the pollutant’s degradation. The carbon-doped composite denoted the largest surface area and increased the catalyst’s reactive sites on the membrane. The photocatalytic activity test showed that 1% carbon doped on ZnSn(OH)6 prepared at 160°C by hydrothermal method coated on the membrane had the optimal degradation of 89.74% of MB. This study contributes to the ongoing study and development of photocatalytic membranes for the photodegradation of wastewater treatment.

Development of wastewater treatment technology with purpose of their reuse in process of obtaining cotton pulp

Today, an urgent problem is developing a technology for producing cotton cellulose from low-grade linters with the rational use of water resources. This issue is especially relevant for the Republics of Central Asia. Also, the development of a technology for the production of cotton pulp would provide an acute shortage of pulp and paper, protect the environment, reduce energy costs, reduce water and chemical costs, and rationally use available raw materials. The paper presents the results of studies on the possibility of cleaning waste liquor and wash water for reuse in obtaining cotton cellulose. The object of the study is the cooking solution, spent liquor, used water after pulping and washing, their sanitary characteristics, and the quality indicators of the products obtained. The discoloration of wastewater, the residual amount of sodium hydroxide, the change in the optical density of the cooking solution, and the chemical composition of the waste liquor and washing water after discoloration were experimentally studied.