Color Reduction Research Articles

THE EFFECTIVENESS OF COAGULANTS FOR TURBIDITY AND COLOR REMOVAL FROM NATURAL WATER

In this work, the effectiveness of the use of coagulants Al2(SO4)3·18H2O and RM-1 in reducing the level of turbidity and colour (reduction in colour) of natural water was investigated. The object of the study is natural water, namely water from the Dnipro River. The results showed that the optimal dose of coagulant Al2(SO 4)3‧ 18H2O was 10.0 mg dm-3. The optimal dose of coagulant RM-1 was also 10.0 mg dm-3. Residual turbidity and colour are reduced to 0.0 mg dm-3, 12.50, 190, when using Al2(SO4)3·18H2O and RM-1, respectively. Since the residual concentration of aluminium in purified water in all samples after purification with coagulants was less than 0.05 mg dm-3, it is reasonable to use these coagulants, as they do not have a negative effect on the health of consumers. The efficiency of using the RM-1 coagulant to remove turbidity and reduce the colour of the natural water of the Dnipro is high, so this coagulant has the potential to be chosen as a new coagulant.

Mitigating pollutants in textile dye wastewater with Aloe vera (L.) Burm. f. and Abelmoschus esculentus (L.) Moench: A study on treatment efficacy

Textile wastewater, particularly those containing dyes, presents significant threats to environmental quality and human health. This study assessed the efficacy of Aloe vera (L.) Burm. f. and Abelmoschus esculentus (L.) Moench (Okra) in removing pollutants from textile dye effluent collected in Dindigul, Tamil Nadu. The effluent samples were treated with varying doses of phyto-coagulants (0.02g, 0.04g, 0.06g, 0.08g, 0.10g, and 0.12g), as well as isolated polysaccharides from Aloe vera and Okra, to identify optimal strategies for reducing color, Total Dissolved Solids (TDS), and Chemical Oxygen Demand (COD). The findings revealed that the phyto-coagulants, particularly Okra polysaccharides, significantly reduced pollution levels, achieving a 90% reduction in color, 96% reduction in TDS, and 82% reduction in COD. To further understand the mechanism of pollutant removal, GC-MS, FTIR, and Zeta potential analyses were conducted. This study highlights the effectiveness of natural coagulants in mitigating environmental pollution and preventing the entry of harmful chemical contaminants into the food chain. The study supports the potential of Aloe vera and Okra as sustainable and eco-friendly solutions for addressing the environmental challenges posed by textile wastewater pollution.

Evaluation of zinc oxide nanocomposites and L-ascorbic acid on meat quality during transport induced stress in birds of Sonali breed

The study assessed the efficacy of phytofabricated zinc oxide nanoparticles (CF-ZnONPs) and L-ascorbic acid in alleviating pre-slaughter transport induced stress in birds of Sonali breed (Cross bred of Rhode Island Red cocks and Fayoumi hens). A total of 120 birds were divided into four groups: negative control (T1) which were loaded in vehicle but not transported, Positive control (T2) birds were transported without any prior supplementation, T3 and T4 birds were transported with prior supplementation (a day before transportation) of CF-ZnONPs @100 µg/ml and L-ascorbic acid @82 µg/ml in drinking water. Results obtained observed significant reduction in live weight, meat colour and pH but increased drip loss percentage in T2 group. Significantly elevated H/L ratio was recorded in all transported groups. Increased cortisol and TSH levels and decreased thyroid hormones, Triiodothyronine and thyroxin (T3 and T4) levels were recorded in T2 group. However, supplementation with CF-ZnONPs and L-ascorbic acid notably reversed these adverse effects, restoring meat quality and other metabolic profiles. Notably, ascorbic acid exhibited greater efficacy, suggesting its superior role in mitigating transportation-induced stress. Overall, these findings highlight the importance of antioxidant supplementation in alleviating transport induced stress in birds.

The effect of composite edible coatings on the postharvest quality of “Hass” avocado fruit treated at different harvest maturities

Edible coatings play a critical role in reducing postharvest losses during storage and supply chain of horticultural commodities. The present study evaluated the efficacy of different concentrations of moringa leaf extract (MLE) combined with carboxymethyl cellulose (CMC) edible coating in preserving the quality and extending the shelf life of “Hass” avocado. Fruit were harvested at different stages of maturity and evaluated by dry matter content. Different concentrations of moringa (8 and 16%) extracted with chilled ethanol (100%) and functionalized with CMC (5%), were used to treat the fruit. Treated fruit were then stored at 5.5 ± 1°C and 90 ± 5% RH for 28 days plus an additional 7 days at 23°C. The changes in physicochemical and biochemical fruit attributes were evaluated at weekly intervals. The application of moringa and CMC-based edible coatings preserved the phenolics, flavonoids, and antioxidant activity of “Hass” avocado. The treatments significantly (p < 0.05) reduced the loss of weight and firmness. Furthermore, treated fruits were found to have a delayed color change and reduction in sugar concentration, particularly mannoheptulose, compared to the control treatment. Therefore, edible coatings prepared by combining CMC and MLE could be the best alternative for substituting the currently used health-compromising synthetic chemicals.

Degradation of Azo-dye (Disperse Red) Using Rhizosphere Bacterial Consortium

This study investigates the degradation of the azo dye (Disperse Red) using a rhizosphere bacterial consortium. Standard microbiological and molecular techniques were employed to isolate and identify organisms from rhizosphere soil. Degradation of azodye was carried out in a fabricated anoxic and oxic chambers with hydraulic retention time of 40hrs. Initial identification of the bacterial isolates through Gram’s reaction and biochemical tests revealed the presence of organisms belonging to the genera Pseudomonas, Lysinibacillus, and Citrobacter. Molecular and phylogenetic analyses confirmed the isolates as Pseudomonas aeruginosa, Lysinibacillus sphaericus, Pseudomonas chengduensis, and Citrobacter freundii. During the preliminary testing, the degradation efficiency was assessed under varying glucose concentrations. Higher decolorization rate of 56.17% was observed in the medium with 10% glucose after 72 hours, while the medium with 5% glucose achieved a 44.17% colour reduction. Notably, lower degradation rates recorded were 11.96% and 12.85% for the 5% and 10% dye enhance glucose mineral salt media, respectively. However, During the actual degradation testing in a double-chamber system enhanced with biochar, the first anaerobic cycle achieved a maximum decolorization of 71.95% after 94 hours, with the first aerobic cycle further enhancing degradation to 90.51%. The second anaerobic cycle increased degradation to 94.78%, and the final aerobic cycle achieved a decolorization of 98.47%. These results show that the rate of Disperse Red degradation is highly dependent on glucose levels and alternating anaerobic-aerobic conditions. This study demonstrates the potential of using rhizosphere bacterial consortia to bioremediate wastewater contaminated with azo dyes, offering an efficient and sustainable method of environmental management. The results underline the need of optimizing ambient conditions to increase microbial degradation processes.

Aptamer regulated peroxidase-like activity of cobalt oxyhydroxide nanosheets for colorimetric detection of kanamycin.

A straightforward label-free colorimetric aptasensor utilizing the aptamer-enhanced peroxidase-like activity of cobalt oxyhydroxide (CoOOH) nanosheets has been established for kanamycin detection. In the kanamycin-free state, aptamers adsorb onto the CoOOH surface through electrostatic forces, enhancing the peroxidase-like activity of CoOOH and thereby resulting in a strong absorption signal and a yellow hue in 3,3',5,5'-tetramethylbenzidine (TMB) upon termination of the reaction with a stop solution. Conversely, upon the introduction of kanamycin, aptamers and CoOOH nanosheets compete for binding to kanamycin, resulting in a significant decrease in the number of aptamers bound to CoOOH. As a result, the activity of CoOOH diminishes, leading to a corresponding reduction in coloration and absorbance of the solution. Hence, the quantitative determination of kanamycin could be realized by analyzing the absorbance variations. Under optimal conditions, the aptasensor demonstrated high sensitivity and specificity, with a linear detection range from 500nM to 5µM and a detection limit as low as 54.6nM. Moreover, the aptasensor effectively identified kanamycin in river water samples, achieving a recovery rate between 91.7% and 102.1%. This approach offers good practicability and provides a novel platform for kanamycin detection in environmental samples.

Advanced Dehydration Techniques Standardized for Flowers of Gomphrena globosa L.

The present experiment was conducted on standardizing dehydration technique for Gomphrena globose flower by using embedding drying methods in room temperature and hot air oven at 55°C was done. The experiment consisted of 10 treatments with 3 replications designed in completely randomized design. Treatments used were as; T1-Boric acid (room temperature), T2-Silica gel (room temperature), T3-Sand (room temperature), T4-Sawdust (room temperature), T5-Cocopeat (room temperature), T6-Boric acid (hot air oven at 55 °C), T7-Silica gel (hot air oven at 55 °C), T8-Sand (hot air oven at 55 °C), T9-Sawdust (hot air oven at 55 °C), T10-Cocopeat (hot air oven at 55 °C). The most reduction in flower fresh and dry weight, measuring 2.36 and 2.12 g, was observed in Treatment T7 (Silica gel with hot air oven at 55°C), where silica gel was employed as the desiccant. The least reduction in flower fresh and dry diameter, measuring 1.92 and 1.81 g, was observed in Treatment T7 (Silica gel with hot air oven at 55°C), where silica gel was employed as the desiccant. The highest drying duration for gomphrena in T3 (Sand) and T4 (Sawdust) treatments was 234.21 and 210.40 hrs at room temperature. The boric acid and silica gel demonstrated outstanding performance in terms of quality parameters, including texture, color, and overall appearance. Among all treatment, embedding drying with silica with hot air oven dehydration at 55°C was found to be best in term of reduction in weight, diameter and overall colour, appearance and texture of Gomphrena globose flowers.

Mechanistic investigation of azo dye removal from carbon-deficient dyeing wastewater using horizontal-vertical constructed wetlands

Azo dye degradation can be achieved by simulating a series of anaerobic and aerobic conditions within the constructed wetland (CW) system. The current investigation evaluated the effectiveness of a baffled horizontal-vertical CW system, planted with Typha angustifolia, simulating anaerobic-aerobic conditions to treat carbon-deficient synthetic dyeing wastewater containing 100 mg/L Reactive Yellow 145 (RY145) azo dye. In the absence of an available carbon source in dyeing wastewater, an optimum quantity of sodium acetate was supplemented as the substrate for microbial degradation of RY145. Influent dyeing wastewater characteristics were 5555 ADMI colour, 461 mg/L chemical oxygen demand (COD) and 39 mg/L total nitrogen (TN). During the operation period, the CW system achieved 97% colour, 87% COD, 95% ammonium nitrogen (NH4+-N) and 71% TN removals at 4 d hydraulic retention time (HRT). Favourable environmental conditions, such as low redox conditions and substrate availability in horizontal CW, contributed to a significant reduction in colour (96%). Most TN reduction (67%) happened in horizontal CW by denitrification and plant assimilation. The metagenomic study revealed that Proteobacteria, Bacteroidetes, Chloroflexi and Firmicutes were responsible for pollutant degradation within horizontal CW. The UV–visible spectra and high-resolution liquid chromatograph mass spectrometer (HR-LCMS) analysis confirmed that dye degradation intermediates generated from the breakage of azo bonds were eliminated in vertical CW with high redox conditions. The results of the phytotoxicity and fish toxicity experiments demonstrated a substantial toxicity reduction in the CW system-treated effluent.

Optimization of coagulation-flocculation in urban water treatment using Moringa oleifera

Using a safe, easy-to-apply, and cost-effective flocculant to substitute alum is imperative for broadening and improving water quality in rural areas where conventional water treatment methods are inaccessible. This study aimed to assess the efficacy of Moringa oleifera seeds (MOS) in treating urban wastewater. The experiment involved adding random quantities ranging from 0.1 to 0.5 g/500 ml of water. Various properties of the wastewater were evaluated, including turbidity, chemical oxygen demand (COD), and color. The optimal dosage of MOS was determined to be 0.3 g/ 500 ml, resulting in the most significant reduction in color and turbidity. The highest reduction percentage was observed for turbidity (87.5 %), followed by COD (58.8 %) and color (49.76 %). The characteristics of dissolved organic matter notably influence the coagulation behavior of MOS. Based on these findings, the study proposed a coagulation mechanism for Moringa.

Evaluasi karakteristik gula kelapa cair dengan variasi penggunaan laru dan penambahan ekstrak rosela

Coconut sugar is a food ingredient made from coconut juice. Nira is easily damaged due to microbial contamination. The destruction of sap can be prevented by the use of laru and variations of rosella constituencies. This study aims to examine the effect of the use of laru on the quality of sap and liquid coconut sugar, the effect of variations in the addition of rosella extract on the quality of liquid coconut sugar, and the influence of the combination of variations in the use of laru and the addition of rosella extract on the quality of liquid coconut sugar. This study used experimental methods with a Complete Randomized Design (RAL). The factor studied was the use of nira preservatives: Non Laru and Laru. The second factor is the variation in the concentration of added rosella extract which is 0; 5; 10; 15 %. The variables observed were pH, Brix, reduction sugar, moisture content, viscosity, colour, aroma, taste, preferences, texture and flavour. The use of laru affects the pH, reduction of sugar, colour, aroma, taste, preferences, texture and flavour of liquid coconut sugar. The higher the concentration of rosella extract administered will lead to a decrease in pH, ̊Brix, viscosity and an increase in moisture content. The higher the concentration of rosella added to liquid coconut sugar, the browner the colour of liquid coconut sugar will be, the distinctive aroma will be mushier, the sweetness is slightly reduced, the level of liking decreases, and the texture is as good as diluted and the flavour of liquid coconut sugar also decreases.

COD, color, and turbidity reduction from surface water using natural coagulants: Investigation and optimization

Several researchers have established the performance of natural coagulants in treating water via coagulation and flocculation process. This study is aimed at investigating the use of Linseed-based natural coagulant for treating surface water, especially in rural areas where most people cannot afford the high cost of chemically coagulant-treated water. The influence of various experimental parameters such as coagulant dosage, pH, and stirring time on the percentage of color, chemical oxygen demand (COD), and turbidity removal has been studied. The experimental results showed that the use of Linseed has shown high removal of color (97.76 %), turbidity (96.58 %), and COD (90 %) at pH values of 3.03 using a 1.75 g/L coagulant dosage and a stirring time of 37.37 minutes. Upon the numerical optimization of the parameters investigated, the removal of color, turbidity, and COD were found to be 94.0 %, 95.5 %, and 86.35 %, respectively, at pH of 7.0, coagulant dosage of 2.5 g, and stirring time of 40 minutes. The findings showed that Linseed has excellent coagulating competence and is very effective in the removal of impurities from surface water.

Integrated Ozonation and Photocatalysis to Remove Pollutants for Reuse of Rainwater

Rainwater is susceptible to pollutants such as sulphur dioxide, nitrogen oxides, heavy metals, and particles, posing challenges to water quality protection and soil degradation, impacting ecosystems and agriculture. The study focuses on the effectiveness of combined ozonation and photocatalysis in improving physicochemical parameters and reducing toxic substances. Integrated analyses, including ecotoxicological assessments, evaluate the impact of treatment on actual rainwater samples. The results indicate significant reductions in color, heavy metals, and organic pollutants after treatment. Microbiological analyses reveal the inactivation of E. coli, which is crucial for safe water reuse. Ecotoxicity studies show no toxicity to crustaceans, but slight toxicity to algae and bioluminescence bacteria in post-treatment samples. Genotoxicity assessments indicate that there is no detectable DNA damage. Overall, the study highlights the complex nature of rainwater pollution and the efficacy of photocatalytic ozonation in reducing contaminants, underscoring the need for more research to ensure sustainable water resource management.

Treatment of real wastewater from a paper mill with combined treatment of electrochemical oxidation and ultrasonic irradiation

This study presents the effect of combined treatment of ultrasonic irradiation (UI) and electrochemical oxidation (EO) on real wastewater from a paper mill. Firstly, wastewater was treated with UI and EO separately and then it was treated with UI and EO together. Separate UI treatment of wastewater was able to achieve COD and color reduction by 40 % whereas the separate EO treatment was able to achieve COD and color reduction by 70–90 % (depending upon the combination of various parameters like current density, electrolyte concentration, pH, magnetic stirrer speed). However, when both processes were combined, they were able to achieve 100 % reduction of COD and color and that too in very less operation time (less than 80 min). Platinum coated titanium (Pt/Ti) sheet was used as anode and stainless steel sheet as cathode. Combined treatment was carried out at optimal conditions derived from separate EO treatment. These optimal conditions were 6 mA/cm2 current density, 1.5 gm/l NaCl concentration, 6 pH, and 400 rpm magnetic stirrer speed. UI not only provided an alternative way of creating turbulence but also helped in decomposing the pollutants by weakening their bonds. Moreover, it was found that energy consumption in combined UI and EO treatment is much less than the energy consumption in separate EO treatment with magnetic stirrer.

Physico-Chemical Charateristics Of Goat’s Milk Soap

Abstract This research aimed to observe the physico-chemical characteristics and acceptability of goat’s milk soap at different storage times. The goat milk soap was made using cold process and coconut oil as the main materials and stored at room temperature of 25°C for 0 and 30 days. Raw milk material was tested for alcohol test, density, water content, and fat content as well as for the cream. The physical characteristics (hardness and foam ability) and chemical characteristics of soap (pH, saponification value, peroxide value, and free fatty acids) were determined by analysis of variance Paired T-Test. Acceptability tests obtained were then analyzed by non-parametric Kruskall Wallis Test. The results showed that goat’s milk had 1,028 kg/m3 of density, 84,25 % of water content, and 3,025% of fat content. The results have showed that Soap which was 30 days in storage had a higher hardness (7,22±2,80 kg/cm2), more stable foam (7,25±4,21%), lower pH value (11,05±0,38), lower peroxide value (4,00±3,04 meq/kg), higher saponification value (214,30±6,64 mg KOH/g), and higher free fatty acids (0,21±0,01%) than fresh goat milk soap. 30 days aged goat milk soap have showed reduction in colour and texture while off odor of soap was higher than fresh goat milk soap.

Casein‐based nanocarriers for encapsulation of propolis extract: Design, fabrication, and characterization

AbstractBackgroundPropolis exhibits multiple biological and pharmacological properties attributed to the presence of natural bio active compounds. In spite of its potential healthy effects, its use in health‐food and pharmaceutical products is very restricted due to its intense aroma, highly unstable, low aqueous solubility, and low bioavailability. The purpose of this study is to fabricate an appropriate, stable, and biodegradable casein‐based nanocarrier as propolis delivery system. Propolis‐loaded casein nanocarriers were prepared at different propolis extract/caseinate ratio and assessed for physicochemical, structural, and thermal properties.ResultsThe nanocarriers showed an increase of particle size augmenting propolis extract/caseinate ratio and caseinate concentration. Image processing studies revealed an increase in L* parameter (89.743), while b* parameter revealed a reduction in the yellow color (14.655) increasing the amount propolis extract in the nanocarrier. Surface photomicrographs evidenced that an increment of propolis extract decreased the network compactness of the nanocarriers correlated with the lower entrapment of propolis extract into carriers at higher propolis extract/caseinate ratio. X‐ray diffraction pattern suggested that propolis encapsulation produced a decrement in the caseinate crystallinity while differential scanning calorimetry and thermogravimetric/differential thermal analysis thermograms evidenced an increment of thermal stability of nanocarrier with increasing propolis extract content.ConclusionPropolis extract encapsulated within casein nanocarriers represented convenient physicochemical attributes and could provide as bioactive load in food/medical system.

Removal of COD, BOD and color of different industrial effluents using activated neem char

Characterization of industrial effluent i.e. sugar, dye, paper and pulp; and combined effluent is performed using the standard method, which indicates higher amount of pollutants exist in all the effluents. Adsorptive batch treatment is conducted using activated neem leaf powder (a-NLP), in which adsorbent dose, temperature and contact duration are the factors selected for this study to reduction of COD, BOD and color from individual and combined wastewater. Maximum elimination of COD, BOD and color is attained upto 93.4-82.4, 82.6-75.9 and 93.4-86.1 % respectively from sugar, dye, paper-pulp and combined effluent respectively at dosage of 23 gm/L a-NLP, temperature of 300 K and contact duration of 60 min. Adsorption isotherms such as Freundlich, Langmuir, Dubinin-Raduskevich, Flory-Huggins and Temkin Isotherm are examined in order to explore the adsorption mechanism. The reaction rate is estimated by different kinetic models (Pseudo First-, Pseudo Second-order, Intra-particle and Elovic equation). From correction coefficient value, Freundlich isotherm and Pseudo First-order govern adsorption process. Different thermodynamic parameters such as free energy of adsorption (∆G°), enthalpy change (∆H°) and entropy change (∆S°) are also accessed, which indicates that adsorption is thermodynamically feasible. Solvent desorption is carried out to regenerate this adsorbent for three consecutive cycles.

Aluminum Waste as Electrode for Home Textile Industry Wastewater Treatment using Batch Electrocoagulation Process: Studies on Operating Parameters

The manufacture of the Sasirangan home textile industry involves coloring and dyeing processes using synthetic dyes in large quantities. These contaminants of dyes and organic materials would cause high color and chemical oxygen demand (COD) contaminants values. This study aims to characterize the wastewater of batik-modified Sasirangan and determine the effect of current density and length of operating time on color removal and reduction of COD in Sasirangan home textile industry wastewater through the batch electrocoagulation process. The method used in this research is an electric current flowing in the same direction to the Sasirangan home textile industry wastewater in a reactor with dimensions of 310 180 240 mm3. The electrode used is aluminum alloy type 1100. The aluminum/aluminum (Al/Al) electrode is used in this electrocoagulation (EC) process, then connected to a direct current (DC) power supply. The experiment was carried out at room temperature using an electrode distance of 2 cm with variations in the time of the electrocoagulation process for 15–120 minutes. The experiment was repeated for variations in pH (4–9) with a current density of 3.5–5.5 mA/cm2. Furthermore, an analysis of the color removal and the decrease in the concentration of COD was carried out. The results showed that the contaminant content in Sasirangan home textile industry wastewater decreased significantly, whereas the optimal conditions for the EC reaction were determined using color and COD removal efficiency parameters. The decrease in color and COD concentrations occurred at a current density of 5.5 mA/cm2 with a pH of 4 for 120 minutes, around 1110 PtCo and 90.4 mg/L of COD, respectively

Characterisation of physicochemical properties, anti-hyperglycaemic effects, and probiotic potentials in fermented pumpkin drink utilising Lactobacillus mali isolated from water kefir

Pumpkin has been reported to be a good probiotic delivery vehicle, but it has a short shelf life, is susceptible to enzymatic browning, and prone to microbial spoilage. Pumpkin could be transformed into a value-added beverage through the fermentation by LAB. In the present work, the probiotic viability, physicochemical, antioxidative, antihyperglycemic, and sensory properties of Lactobacillus mali-fermented pumpkin drink (FPD) during eight weeks of refrigerated storage at 4°C were investigated. There were significant reductions (p < 0.05) in colour, pH, texture characteristics, and antioxidant properties after four weeks of storage. FPD exhibited total phenolic content ranging from 83.75 to 90.75 mg GAE/mL, total flavonoid content ranging from 47.01 to 50.01 mg QE/mL, FRAP reducing power ranging from 160.76 to 169.76 µmol Trolox equivalent/mL, and DPPH scavenging activity ranging from 52 to 54.56% during storage. FPD's total soluble solids decreased (p < 0.05) from 0.60 to 0.02 °Brix, while concentrations of ethanol (0.62 to 1.2%, v/v), lactic acid (0.03 to 0.11 g/L), and acetic acid (0.02 to 0.18 g/L) significantly increased (p < 0.05) over eight weeks of storage. L. mali strain within FPD maintained its viability (p > 0.05) under simulated gastrointestinal conditions, with 8 - 9.1 log CFU/mL for 28 days at 4°C. FPD retained up to 90% α-glucosidase enzyme inhibition throughout the 28 days storage period. Sensory evaluation showed that FPD's attributes remained unchanged (p > 0.05) during the initial four weeks of storage, with an overall acceptability score ranging from 6.56 to 6.88. In conclusion, FPD remained stable in terms of physicochemical, antioxidative, and sensory properties, as well as probiotic viability and anti-hyperglycaemic effects during 28 days of refrigerated storage. This highlights FPD’s potential as a functional beverage, presenting an innovative method to utilise pumpkin as an effective probiotic carrier.

Ensemble machine learning as a mathematical approach to predict high-voltage electric field-assisted removal of color and oxidative indices from soybean oil using the activated porous electrodes

Porous electrode materials provide a large surface area for electrochemical reactions and facilitate ion transport efficiently. By optimizing the design and properties of porous electrodes, it is possible to enhance the bleaching performance. In this research, three machine learning (ML) algorithms, namely Support Vector Regression, Ridge Regression, and Decision Tree Regression were utilized for predicting the bleaching efficiency under different conditions of HVEF-assisted bleaching (HVEFAB). Subsequently, the outcomes of these models were compared to ensemble models created by combining the algorithms as mentioned earlier using three techniques including bagging, boosting, and stacking. The levels of chlorophyll and carotenoids were reduced as a result of increased voltage, modification in the electrode surface, number of cathode-anode, and the presence of an inert electrolyte. Meanwhile, the reduction of red color and chlorophyll pigments was more significant than yellow color and carotenoid pigments. Moreover, the application of HVEFAB can potentially decrease the levels of polar compounds, such as oxidative compounds on the electrode surface. Based on the MSE, MAE, and R2 metrics, the algorithms' efficacy in forecasting outputs 1 (color index) and 2 (oxidative index) can be ordered as follows: Stacking > Boosting > Bagging > Decision Tree (DT) > Ridge > Support Vector Regression (SVR). The findings demonstrate that integrating these three models, mainly through the stacking technique, substantially improves the accuracy of the predicting model. Particle swarm optimization (PSO) and polynomial regression rather than RSM represented a superior model to predict red color removal.

Treatment of real textile effluent containing indigo blue dye by hybrid system combining adsorption and membrane processes

The rapid expansion of the textile industry in Tunisia has resulted in ever-increasing discharges of wastewater, making it necessary to set up treatment systems allowing i) its discharge into the environment or ii) to recycle the water in the textile plant. In this study, several unitary operations were tested in order to improve the treated water quality. Thus, the following unit operations were applied: adsorption using Natural Clay (NC) and Powdered Activated Carbon (PAC), ultrafiltration (UF) and nanofiltration (NF) individually or in synergy: UF, nanofiltration, PAC-UF, NC-UF, UF-NF et Adsorption-UF/NF. The experiments were carried out on real textile effluent containing Indigo blue dye. A threshold concentration was observed above which performance no longer increases. NF alone showed better reduction of COD (67%), color (78%), and turbidity (98%) than UF alone (26%, 48%, 95%, respectively). The coupling UF–NF showed a clear improvement in water quality in terms of color (99%) and COD (98%) with an improvement in the NF flux from 67.81 L/h.m2 to 90.62 L/h.m2. No fouling was observed for NF while it is significant during UF. The used of adsorption as pretreatment to filtration leads to an enhancement of the treatment performances with a removal of 99.9%, 99.5% and 79.5% respectively for turbidity, color and COD for NC-UF and a removal of 100%, 99.4% and 79.6% respectively for turbidity, color and COD for PAC-UF. Moreover, the addition of adsorbent controls the fouling and a constant and high flux is quickly attained and remains stable over time. The use of natural clay as adsorbent represents an economically profitable solution since it can be obtained locally and the clay used can be reused in the ceramic industry as an additive for road surfacing without the need for regeneration.