Color Reduction Research Articles

Potential use of tin tetrachloride and polyacrylamide as a coagulant-coagulant aid in the treatment of highly coloured and turbid matured landfill leachate

The effectiveness of using natural coagulants as flocculants and tetravalent metal salts as coagulants in the treatment of landfill leachate remains debatable. The main aim of this study is to assess how well the polymer polyacrylamide (PAM) could interact as a coagulant, coagulant aid or flocculant with the tetravalent metal coagulant tin tetrachloride (SnCl4) in the removal of contaminants from leachate. Thus, this study examined the performance of a mix of the rare four-valence metal SnCl4 as a coagulant and compared it with the organic-based coagulant and flocculant PAM (molecular weight of 3.46 × 104 Da and zeta potential of −57.9 mV). Optimal rapid/slow mixing and settling times were evaluated by performing a standard jar test. The optimal rapid mixing rates for SnCl4 and PAM were 220 rpm and 120 rpm, respectively. At these speeds, 98.4% reductions of colour and 98.7% of SS were obtained by using SnCl4 as opposed to 35.1% and 15.3% reductions for colour and SS, respectively, by using PAM. The best slow mixing speed for both coagulants was 60 rpm, with 98.4% and 98.6% reductions of colour and SS, respectively. Whereas PAM resulted in a 40.4% reduction in colour and an insignificant reduction in SS. SnCl4 performed better in colour and SS treatment at a faster settling time (40 min) than PAM, which required a settling time of 45 min. The optimal conditions for the application of SnCl4 as the sole coagulant were pH 8 and 10 000 mg/L SnCl4. Under these conditions, SnCl4 resulted in almost complete reductions in colour and SS. However, PAM was ineffective when applied as the sole coagulant. When 100 mg/L PAM was introduced as a coagulant aid, the dosage of SnCl4 decreased to 6000 mg/L. At this dosage, SnCl4 caused 94.3% and 95.9% reductions in colour and SS, respectively. After treatment, the settling rate and sludge volume index also significantly increased to 0.61 cm/min and 84.2 mL/g, respectively. Therefore, SnCl4 and PAM could be used together to remove pollutants effectively.

Comparative study of the efficacy of a Chelating Cream in patients with bruises after blepharoplasty: a pilot study

Purpose: Blepharoplasty is a common surgical technique, performed mainly for aesthetic purposes and for functional disorders of the periorbital, which corrects excess skin of the upper eyelids or excess fat in the lower bags. As a side effect, periorbital hematomas usually occur, which can be annoying for patients. Ice water compresses and head elevation are used, without scientific evidence, for recovery, but specific creams, such as those with lactoferrin, can accelerate tissue repair processes. The study aimed to assess the efficacy of a cream containing lactoferrin encapsulated in liposomes, Kelador®, to reduce post-blepharoplasty bruises. Methods: This controlled, prospective, randomized, single-centre pilot clinical study was conducted at the Barraquer Clinic in Barcelona, Spain. All patients underwent a blepharoplasty, and periorbital hematomas were treated with a Chelating Cream (Kelador®). Patients were followed up two and nine days after surgery, where clinical data and photographs were taken. Images were assessed through an objective analysis method developed with the ImageJ® software. Results: Nineteen patients were enrolled, 16 women and three men. The median age was 60.37 years (SD 14.22), and the median of treatment days was 8.2 (SD 1.6). The mean Reduction % in the treated eyes was 33.3 (SD 31,0), and in untreated eyes, 17.7 (SD38,1). Differences were statistically significant (p = 0.00667). Conclusions: Using a Chelating Cream containing lactoferrin encapsulated in liposomes, such as Kelador®, accelerates the reduction of bruise colour after a periocular intervention such as blepharoplasty.

Investigation of Blue Coloration in Sapphires Using X‐Ray Absorption Near‐Edge Structure Spectroscopy (XANES)

AbstractThe color of blue sapphire has long been explained using the intervalence charge‐transfer (IVCT) [Fe2+‐Ti4+ and/or Fe2+‐Fe3+] theory, in which the blue can be reduced by thermal (heat) treatment in oxidizing condition to alter Fe2+ (FeO) to Fe3+ (Fe2O3). However, the color mechanism is not well understood. Recently, the band gap theory proposes that iron (Fe) in sapphire always presents as Fe3+, and the blue is caused by Fe3+‐Ti4+ pair, hence thermal treatment does not alter Fe oxidation. The UV–Vis–NIR, Proton‐Induced X‐ray Emission (PIXE), and X‐ray Absorption Near‐Edge Structure (XANES) techniques are carried out before and after treatment to prove this issue. The absorption spectra are slightly lower after treatment, corresponding with the reduction of blue color in all samples. XANES data reveal mixture of Fe2+ and Fe3+ (mainly Fe3+) in all samples, and show insignificantly change after heated which rather supports the band gap theory. However, calculation based on linear combination fitting (LCF) technique shows a slight change in the oxidation from Fe2+ to Fe3+ which rather supports the IVCT theory. It is noted that the highest change is found in the lowest ratio of Fe:Ti sample, while the lowest change is conversely.

EVALUATING THE LIGNIN DEGRADING POTENTIAL OF INDIGENOUSLY ISOLATED FUNGAL STRAIN 81 FROM PAPER AND PULP INDUSTRY WASTE WATER

Lignin is a phenolic biopolymer and a complex recalcitrant compound found in the wastewater effluent of the pulp and paper industry. Wastewater generated by the pulp and paper industry is having lignin as a major part in the form of black liquor, which poses serious hazards for the ecosystem along with health risks. Biological methods including the use of micro-organisms to degrade lignin by the enzymatic battery of various bacteria and especially fungi proved out to be effective. The present study includes the application of indigenously isolated fungal strains 81 from the effluent wastewater of a local pulp and paper industry of Pakistan. The strain was grown on lignin amended minimal salt media for the screening of best lignin degrader for determining their capability of lignin degradation and color reduction. Absorbance for lignin degradation and color reduction was measured at 280nm and 465nm respectively on the spectrophotometer. The results proclaim fungal strain 81 identified as Aspergillus fumigatus, after molecular characterization (accession no. MW132910 in NCBI data base) possess the potential to degrade lignin. Hence, it could help in the removal of lignin from toxic industrial wastewater.

Phytoremediation Processes of Sasirangan Textile Industrial Wastewater Treatment using Water Hyacinth

The growth of the textile industry, including the Sasirangan textile industry, is increasing yearly, producing large amounts of liquid waste. Generally, this wastewater is discharged into the environment without treatment, becoming a source of environmental pollution. Therefore, it is crucial to reduce these pollutants. Various methods, not only physical and chemical but also biological methods, are available to remediate wastewater. Phytoremediation has provided an economical, environmentally friendly, and aesthetic solution to remediate wastewater. This study aimed to utilize the Water Hyacinth plant as a phytoremediator and determine its effect in reducing Total Suspended Solid and colors in the liquid waste of the Sasirangan textile industry. This research begins by preparing Water Hyacinth plants. Next, the characterization of Water Hyacinth roots using FTIR and SEM. Finaly, the acclimatization of water Hyacinth, followed by a phytoremediation process for 15 days. Based on the results of the characterization of Water Hyacinth roots with FTIR, it shows that Water Hyacinth roots contain functional groups O-H strain, C-H vibrations, C=O strain, C-H deformation, and C-O stretching. Observations with SEM showed that the roots of Water Hyacinth were extremely unstructured and had pores. However, it has cavities which are pores in cellulose. The significant decrease in Total Suspended Solid was at 9 days of phytoremediation, which was 54 mg/L (71.12% removal). The optimum color reduction within 9 days of phytoremediation was 81.5 PtCo (92.26% removal). The presence of these functional groups and pores, strengthened by the analysis of Total Suspended Solid and colors, showed that Water Hyacinth could reduce levels of Total Suspended Solids and colors in the Sasirangan textile wastewater.

Thermal and chemical modification of wood – a combined approach for exclusive, high-demanding performance products

ABSTRACT Chemical and thermo-chemical modification processes were applied to European beech wood to make it applicable for interior applications which place high demands on aesthetics, hygrothermal and water resistance performance. In particular, the use of modified wood in kitchen tools was foreseen. Impregnation modification with a 20% DMDHEU solution, thermal modification and a combined approach of thermo-chemical modification were compared. All modification processes caused a darkening that for the high modification intensities became close to the aesthetics of some of the most renowned tropical hardwood species. The higher the modification intensity, the higher the improvement. In particular, chemical and thermo-chemical modification processes significantly decreased the liquid water uptake. As regards the mechanical performances while stiffness and strength did not change abruptly and hardness increased, the resistance towards dynamic impacts significantly decreased with every kind of modification process. Thermo-chemical modifications resulted to be an interesting way to improve most of the physical properties of wood with outstanding behaviour in terms of colour appearance and reduction of water uptake in wet environments. An increased brittleness is the weakest point for foreseen fields of application.

Synthesis, Computational, FT- IR, NMR and UV-Vis Spectral Studies of Bioactive 2-(4-fluorophenyl)-4-(4-(4-methoxyphenyl)-5-(3-nitrophenyl)-4H-1,2,4-triazol-3-yl)quinoline

The work describes synthesis of a bioactive molecule 2-(4-fluorophenyl)-4-(4-(4-methoxyphenyl)-5-(3-nitrophenyl)-4H-1, 2, 4-triazol-3-yl)quinoline. The characterization has been done with the help of various spectroscopic techniques followedby in-silico studies including various structural parameters viz. electrostatic potential, electrophilicity (ω), chemical potential(μ), chemical hardness (η), thermodynamic properties at various temperatures, Natural bond orbital (NBO), Non-linearoptical (NLO), electric dipole moment, polarizability and first static hyperpolarizability. Reactivity descriptors were alsoinvestigated to find out the sites liable for electrophilic and nucleophilic attack. The compound was also bio-evaluated for itsantimicrobial and antioxidant activity. It showed significant activity against S. typhi and a positive antioxidant activityshown by reduction in color with percentage inhibition of 89%.

Isolation and characterization of dye-degrading bacteria from batik wastewater

Azo dye is typically dye used in batik industries that is toxic to aquatic organisms and humans. Chemical methods can effectively degrade the dye effluent however they produce more toxic compounds. Biological methods offer an alternative that is more environmentally friendly and produce readily degradable compounds. Dye degrading bacteria can degrade the dyes in the effluent under anaerobic for decolorization followed by aerobic condition to produce readily degradable compounds. The batik wastewater sample was collected in Kelantan, Malaysia and was analyzed for COD, pH, and color. The Horikoshi-II media pH 10 was used to propagate growth of bacteria in the dye effluent. The dye degrading bacteria then was isolated from the dye effluent using serial dilution spread plate and streak plate method; One bacterium was finally selected based on faster growth. The specific growth rate and generation time of isolated bacteria were 0.069 h-1 and 14 h respectively. The isolated bacteria have characteristic producing red pigment and gram-positive bacilli. Overall reduction of color and COD by isolated bacteria were 23% and 41% respectively. The isolated bacteria were identified as Bacillus sp. strain ARNZ2707 via 16S rRNA sequence analysis.

Prediction and optimisation of coagulation-flocculation process for turbidity removal from aquaculture effluent using Garcinia kola extract: Response surface and artificial neural network methods

The goal of this research is to model/optimise aquaculture effluent (AQE) turbidity (TD) treatment with the aid of the extract of Garcinia kola (GKE) used as a coagulant. GKE was characterized via scanning methods. The research entails the optimisation of the process by RSM (response surface methodology) and Artificial Neural Network (ANN) techniques. The sorption component analysis of the coagulation-flocculation (CF) process of TD reduction from AQE was also analysed for its mechanism. SEM revealed that the GKE possesses uneven-sized, porous, and granular-shaped lumps on its surface. FTIR revealed that GKE had a high hydroxyl group which makes it soluble in aqueous media and contributes to attachment sites for the AQE pollutant particles. The process was effectively optimised (%TD = 74.23%, with TDS, COD, BOD, and colour reductions at 81.03%, 67.68%, 68.19%, and 76.89%, respectively) at optimum conditions of time = 30 min, pH = 2, and GKE dosage = 115 mgL−1. The model generated was significant via ANOVA. The pseudo-second-order (PSO) sorption kinetic is the best fit model considering the error estimates. The predominant mechanism of the process is electrostatic interaction, liquid film diffusion and intraparticle diffusion. RSM(R2=0.9567)>ANN(R2=0.9491) for the models' prediction reliability. This study has shown that aquaculture effluent (AQE) turbidity (TD) treatment with the aid of the extract of Garcinia kola (GKE) can be optimised/modelled productively.

Clinical evaluation of the efficacy of fractional radiofrequency for the treatment and reduction of stretch marks: Aprospective study.

Skin resurfacing with fractional radiofrequency results in reepithelization, collagen shrinkage, fibroblast stimulation, and neocollagenesis which may be beneficial for the improvement of various skin lesions. This clinical study was conducted to evaluate the safety and efficacy of fractional radiofrequency device (FRF) for the treatment of striae. Seventeen subjects, totaling 67 treatment zones were evaluated. Subjects had 4 FRF treatment sessions to the striae areas, at 4-weeks interval. 3D-standardized photographs of the treatment area with a 3D camera were used to evaluate striae volumetric improvement from baseline to follow up (FU) visits at 12 and 16 weeks post-final treatment. A satisfaction questionnaire was completed by subjects at each of the follow-up visits. Additionally, the mean scores of the live investigator assessments of Global Aesthetic Improvement Scale (GAIS), Subject Satisfaction Scale, Pain Visual Analog Scale and Tolerability Score were calculated. A total of 15 subjects completed the study (Fitzpatrick skin type I-III, average age 36.2 years) received 4 FRF treatments on multiple different body zones with multiple passes over stretch marks on the abdomen, inner arms, lower buttocks, inner thighs, and/or flanks. Analysis of 3D photographs of the striae affected zones at 16-week FU revealed an average reduction in the striae volume of 19.1%, a reduction of redness of 14.3%, a reduction of pigmentation of 11.2%, and a reduction of striae color of 8.82%. The GAIS improved by 1.7-points when compared to baseline. Treatments were well tolerated with subjects reporting a mean score of 3.8 out of 10 for pain and 3.1 out of 4 for tolerability (indicating the treatment was "tolerable"), with no occurrences of serious adverse events. The average subject satisfaction at 16-week follow-up was 3.1, out of a total of 4, which signified subjects were "satisfied" with their treatment. 3D Image analysis of the treated zones presented overall reductions in the color and texture of striae after four treatments with FRF. A combination of ablation and coagulation introduced by FRF treatment resulted in improvement to the appearance of the treated striae.

Evaluation of application potential of dye-decolorizing peroxidase from Bacillus amyloliquefaciens in bioremediation of paper and pulp mill effluent.

Pulp and paper mill effluent is rich in recalcitrant and toxic pollutants compounds and causes pollution. To find an efficient biocatalyst for the treatment of effluent, a dye-decolorizing peroxidase from Bacillus amyloliquefaciens MN-13, which is capable of degrading lignin, was used for the bioremediation of paper and pulp mill effluent. The dye-decolorizing peroxidase from Bacillus amyloliquefaciens (BaDyP) exhibited high-redox potential to 2, 2'-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) ammonium salt (ABTS), veratryl alcohol, Mn2+, reactive blue 19, reactive black 5 and lignin dimer guaiacylglycerol-beta-guaiacyl ether (GGE). When GGE was used as substrate, BaDyP broke β-O-4 bond of GGE and then oxidize Cα to generate vanillin. The Km values for ABTS and veratryl alcohol were 2.19 mm and 0.07 mm, respectively. The Vmax for ABTS and veratryl alcohol were 1.8 mm/min and 14.12 mm/min, respectively. The BaDyP-mediated treatment of pulp and paper mill effluent led to significant reduction of chemical oxygen demand (COD) and color. When 5% (v/v) of effluent was treated with BaDyP for 12 h at 30°C and pH 2, the removal of COD, color, and lignin was achieved at 82.7, 80.2, and 78.20%, respectively. In detoxification assay, the seeds of Vigna unguiculata grown in treated effluent showed a significant increase in germination rate from 66.7% (untreated effluent) to 90%, and in radicle length from 0.68 cm (untreated effluent) to 1.26 cm, respectively. In the meanwhile, the inhibition of Escherichia coli and Bacillus subtilis by the treated effluent reduced significantly as compared to untreated effluent, indicating high detoxification performance of BaDyP for the treatment of pulp and paper mill effluent. The findings suggest that BaDyP is a potential catalyst for bioremediation of pulp and paper mill effluent, as it is effective in substantial lowering of pollutants load as well as reduces COD, color, and toxicity of effluent.

Removal of Synthetic Dye from Aqueous Solution Using MnFe2O4-GO Catalyzed Heterogeneous Electro-Fenton Process

In the present study, heterogeneous electro-Fenton (HEF) process using MnFe2O4-GO catalyst is employed for the successful removal of dye from aqueous solution. Pt coated over titanium and graphite felt were used as the electrodes. The study focuses on the efficiency of the electrodes and catalyst used for the successful removal of Rhodamine B (RhB) from aqueous solution and the application of the same in real textile wastewater. The effect of various operational parameters like pH, applied voltage, catalyst concentration, initial pollutant concentration and effect of ions were investigated. The optimized condition of the electrolytic system was found as pH 3, applied voltage of 3 V, and catalyst concentration of 20 mg L−1 for the removal of 10 ppm RhB. At the optimized condition, 97.51% ± 0.0002 RhB removal was obtained after an electrolysis time of 60 min. The role of individual systems of Fe, Mn, GO and MnFe2O4 without support were compared with that of catalyst composite. On examining the practical viability in real textile effluent, a significant colour reduction was observed (reduced by 61.24% ± 0.0261 in 60 min). Along with this, the biodegradability enhancement (BOD/COD ratio from 0.07 to 0.21) after treatment was also observed.

Effect of Magnetized Coagulants on Wastewater Treatment: Rice Starch and Chitosan Ratios Evaluation.

Coagulation with synthetic chemicals has been used to treat a wide range of industrial effluents. Herein, the unique characteristics of industrial effluents being detrimental to the environment warrants urgent resource-efficient and eco-friendly solutions. Therefore, the study investigated the use of two magnetized coagulants (chitosan magnetite (CF) and rice starch magnetite (RF)), prepared via co-precipitation in three different ratios (1:2, 1:1 and 2:1) of natural coagulants (chitosan or rice starch) and magnetite nanoparticles (F) as alternative coagulants to alum for the treatment of wastewater. A Brunauer–Emmett–Teller (BET) analyzer, an X-ray diffraction (XRD) analyzer, and energy-dispersive X-ray (EDX) spectroscopy were used to characterize the surface area, crystal structure, and elemental composition of the coagulants. The influences of settling time (10–60 min) on the reduction of turbidity, color, phosphate, and absorbance were studied. This was carried out with a jar test coupled with six beakers operated under coagulation conditions of rapid stirring (150 rpm) and gentle stirring (30 rpm). Wastewater with an initial concentration of 45.6 NTU turbidity, 315 Pt. Co color, 1.18 mg/L phosphate, 352 mg/L chemical oxygen demand (COD), and 73.4% absorbance was used. The RF with a ratio of 1:1 was found to be the best magnetized coagulant with over 80% contaminant removal and 90% absorbance. The treatability performance of RF (1:1) has clearly demonstrated that it is feasible for wastewater treatment.

Reduction of Water Color in a Spinning Disc Reactor

In this study, spinning disc (SD) technology was successfully applied to a synthetic water to remove its color. The preliminary data performed in a regular mixing system using a potential adsorptive material, i.e., double-layered hydroxide of a ZnAlLDH type, did not provide a significant decrease (no more than 10–15%) in the water color content. Thus, ZnAlLDH (2 g/L) was added to the synthetic water containing 50 mg/L Rosso Remazol RB dye that was subsequently fed onto the spinning disc. The SD efficiency was investigated at four different water-supplying flow rates (5.76, 6.00, 7.44 and 8.16 L/h) and four different disc rotational speeds (100, 250, 500 and 800 rpm). The best color removals of 44.39%, 41.14% and 42.70% were obtained at 6 L/h and 250 rpm, 6 L/h and 500 rpm and 5.76 L/min and 800 rpm, respectively, in only a 50 min working time period. In addition, for a relatively low color concentration in water (~30 mg/L dye) and at the lowest electric power consumption, Fenton oxidation was performed in the SD setup for a more advanced color removal of 62.54% within a 50 min time period. Furthermore, two other materials, titanium and aluminium oxides, underwent similar investigations in the SDR setup, and the obtained results were comparatively discussed. The FTIR spectra of each solid material before and after the SD technology application were used to appreciate the dye-retention performance of each material used. The obtained results indicated that the spinning disc technology correlated with the tested materials could significantly improve the water color (over 40% color reduction), this level of color reduction being higher than that obtained following a coagulation–flocculation test (20–28% color reduction), an ion exchange (25–30% color removal) or a sand filtration step (15–20%) applied to the same dye-based water sample. A further increase in color removal could be achieved by using an additional oxidative step (more than 65% color reduction).

Evaluation of scrap metallic waste electrode materials for the application in electrocoagulation treatment of wastewater

The constant need for sacrificial electrodes is one of the limitations of applying the EC in wastewater treatment. Accordingly, this study proposes a sustainable alternative in reusing scrap metallic wastes as electrode materials. Four different types of metallic wastes (beverage cans, used aluminum (Al) foil, scrap iron, and scrap mild steel) are proposed as sacrificial electrodes for grey water (GW) treatment using the EC technique. At electrical current densities (CD) ranging between 5 and 20 mA/cm2, the treatment performance was evaluated for a reaction time of 10 min in terms of the removal efficiency of some key parameters such as color, turbidity, chemical oxygen demand (COD), and electrical conductivity, energy and material consumption, and metal contamination of GW from electrodes. The results demonstrated that using metallic wastes as sacrificial electrodes can achieve a considerable reduction in color, turbidity, COD, and electric conductivity of about 97.2%, 99%, 88%, and 89%, respectively. However, their reuse as electrodes revealed some important concerns. Al foil undergoes quick and substantial perforation and loss of surface area during electrolysis. The scrap iron and scrap mild steel were found to cause metal contamination by increasing Fe ions in the treated GW. Generally, metal scrap wastes can serve effectively as alternative sustainable electrodes. However, further research is recommended regarding the operating costs, which are considered crucial aspects of the EC process in terms of energy consumption and the most efficient method of fabricating the metallic wastes into a form suitable for reuse in the EC technique.

Performance Evaluation of Water Treatment Plant of Kekri, Rajasthan, India

Drinking water is a sole element of human life. The rapidly growing population is adding to the excessive demand for water. Increasing demand for drinking water is rising the over-exploitation of water. Raw water sources require water treatment with a high production capacity of treatment. Present research provides a case study of the water treatment plant of Kekri, Rajasthan, India. In these two water treatment plants water purification efficiency is good as compared to conventional water treatment plants. Adding poly aluminum Chloride as a coagulant increases water treatment efficiency. Many parts of the water treatment plant add coagulation-flocculation, filtration, and disinfection by using poly aluminum chloride. Two water treatment plants with the capacity of 142 MLD and 132 MLD are having the net purifying capacity to remove the turbidity and Color. In this research, it has been found that turbidity removal of 142 MLD and 132 MLD WTP was found about 83.4 and 74.1% respectively. Total dissolved solid of surface reservoir Bisalpur dam found within acceptable limits. Total dissolved solids in Bisalpur dam surface water such as Chloride, Fluoride, and Nitrates were found of 60 mg/l, 0.3 mg/l, and 2 mg/l respectively. The pH value of surface water was found of 7.90 and remains almost constant with the seasonal variation impact. Turbidity and color reduction were found within the acceptable limit according to Indian standard 10500-2012.

GREEN APPROACH FOR THE TREATMENT OF TEXTILE WASTEWATER USING MICROBIAL FUEL CELL AND BIOELECTRICITY PRODUCTION

Microbial fuel cell (MFC) is a green and promising alternative for saving the depleting nonrenewableresources. In the present research, MFC technology is utilized to bring aboutdetoxification of textile wastewater with simultaneous production of electricity. Textile wastewaterhas a high pH value, high concentrations of dyes, organic pollutants, suspended solids, chlorides,nitrates, heavy metals (high BOD and COD values). The high organic load in the wastewatermakes it function as the useful substrate for microorganisms in MFC. Experimental results showedthat MFC using textile wastewater gave excellent electrical output of 546 mV after 60 h of operationIt has been found under the operating conditions of the experiments, there was 90–95% reductionin colour, TDS, BOD and COD of the textile wastewater.

Clarification of Limed Sugarcane Juice by Stainless Steel Membranes and Membrane Fouling Analysis.

The performance of stainless steel membranes with pore sizes of 100 and 20 nm in clarifying limed sugarcane juice was investigated under different operating conditions. An increase in transmembrane pressure (TMP) for the 20 nm membrane from 2 to 5 bar led to an increase in the average flux from 146.6 Lm−2 h−1 to 187.8 Lm−2 h−1 (approximately 9 h). The increase in crossflow velocity from 2 to 5 m/s led to an increase in the average flux from 111.9 Lm−2 h−1 to 158.1 Lm−2 h−1. The increase in temperature from 70 °C to 90 °C caused an increase in the average flux from 132.8 Lm−2 h−1 to 148.6 Lm−2 h−1. Simultaneously, the test produced a high-quality filtered juice with an average of 1.26 units of purity rise. The purity increased with time, and a 99.99% reduction in turbidity and an average 29.3% reduction in colour were observed. In addition, four classic filtration mathematical models and scanning electron microscopy (SEM) analyses suggested that cake formation is the main mechanism for flux decline. Fourier transform infrared (FTIR) spectrometry and energy-dispersive X-ray (EDX) spectrometry indicated that organic fouling is the main foulant. This study demonstrates the potential of stainless steel membranes as filters for the clarification of raw sugarcane juice.

Combination of hydrodynamic cavitation with oxidants for efficient treatment of synthetic and real textile wastewater

In this study, the degradation of direct red 89 (DR89) dye from synthetic wastewater was assessed by lab-scaled hydrodynamic cavitation (HC) combined with different oxidants such as periodate (PI), persulfate (PS), and oxalic acid (OA). The degradation tests were carried out by combining the three oxidants in the absence of HC, and using HC with only one of the oxidants (HC/OA, HC/PS, and HC/PI) or with all combined (HC/PS/OA/PI). In all processes, the degradation constants followed first-order reaction kinetics, being the highest one that of the HC/PS/OA/PI process, equal to 2.01 × 10−1 min−1. The degradation of DR89 was affected by pH, initial dye concentration, and reaction time. The degradation efficiency increased when pH decreased obtaining the best results at pH 3.0 due to favorable conditions for the generation and persistence of radical species. The degradation of the dye improved with increasing dose of OA, PS and PI. The best results were achieved using dosages of OA, PS, and PI of 100.0, 125.0, and 150.0 mg L−1, respectively. The quenching experiments revealed the presence of OH, SO4−, IO3, O2–, and 1O2 in the HC/PS/OA/PI process, while OH, SO4− and IO3 were the dominant responsible radicals. The rate constants of the individual processes were used to calculate the value of the synergetic coefficient of HC/PS/OA/PI process. At the optimum conditions, the calculated synergetic coefficient was 15.39. The effectiveness of the HC/PS/OA/PI process in the removal of color and COD from real textile wastewater was also investigated and exhibited the 96.23 ± 1.92 % and 93.84 ± 0.94 % reduction of color and COD after 70 min reaction time, respectively. The results showed that the combined process can be a useful technology for the treatment of textile wastewater.

Synthesis, Characterization, and Performance Evaluation of Hybrid Waste Sludge Biochar for COD and Color Removal from Agro-Industrial Effluent

Agro-waste management processes are evolving through the development of novel experimental approaches to understand the mechanisms in reducing their pollution levels efficiently and economically from industrial effluents. Agro-industrial effluent (AIE) from biorefineries that contain high concentrations of COD and color are discharged into the ecosystem. Thus, the AIE from these biorefineries requires treatment prior to discharge. Therefore, the effectiveness of a continuous flow bioreactor system (CFBS) in the treatment of AIE using hybrid waste sludge biochar (HWSB) was investigated. The use of a bioreactor with hydraulic retention time (HRT) of 1–3 days and AIE concentrations of 10–50% was used in experiments based on a statistical design. AIE concentration and HRT were optimized using response surface methodology (RSM) as the process variables. The performance of CFBS was analyzed in terms of COD and color removal. Findings indicated 76.52% and 66.97% reduction in COD and color, respectively. During biokinetic studies, the modified Stover models were found to be perfectly suited for the observed measurements with R2 values 0.9741 attained for COD. Maximum contaminants elimination was attained at 30% AIE and 2-day HRT. Thus, this study proves that the HWSB made from biomass waste can potentially help preserve nonrenewable resources and promote zero-waste attainment and principles of circular economy.