Optimum pH Value Research Articles

Investigating the impact of milk protein, inulin, and honey on quality attributes of goat milk yoghurt.

In this present study, a three-factor Box-Behnken, response surface methodology (RSM) design was employed to optimize the skimmed milk powder (SMP)/whey protein concentrate (WPC) ratio (0.25-0.75%w/v) as a source of milk protein, inulin (1-2%w/v), and honey (4-6%w/v) for production of high-quality goat milk yoghurt (GMY). The resulting ANOVA and response surface equations revealed the significant effect (p < 0.05) of these variables on the various attributes such as total solid (%), pH, titratable acidity [(LA) % by weight], syneresis (%), DPPH (% inhibition), viscosity (m.Pa⋅s), whiteness index (WI), and overall acceptability (OA). The coefficient of determination (R2) for all response variables ranged from 0.88 to 0.99. Lack-of-fit tests resulted in non-significant F-values. The optimal conditions were determined as SMP/WPC at 0.36%w/v, inulin at 1.00%w/v, and honey at 6.00%w/v. The optimum values for total solid, pH, titratable acidity, syneresis, DPPH, viscosity, WI, and OA were 22.03, 4.46, 0.77, 6.34, 25.20, 182.30, 76.29 and 8.37, respectively with desirability value of 0.95.

Effect of electrolytic zero-valent iron activated sodium hypochlorite on sludge dewatering performance.

Using electrolytic zero-valent iron-activated sodium hypochlorite (EZVI-NaClO) to pretreat sludge, the capillary suction time (CST) was utilized to evaluate sludge dewaterability. Ammonia nitrogen (NH4-N), dissolved phosphorus, and total phosphorus in the supernatant were used to analyze sludge disintegration. This approach aimed to evaluate the effectiveness of the pretreatment process and its impact on the sludge composition. The migration and transformation of extracellular polymeric substances (EPS), including dissolved EPS (S-EPS), loosely boundEPS, and tightly bound-EPS (TB-EPS), were analyzed by detecting protein and polysaccharide concentrations and three-dimensional fluorescence excitation-emission spectroscopy (3D-EEM). The sludge particle properties, including sludge viscosity and particle size, were also analyzed. The results suggested that the optimal pH value, NaClO dosage, current, and reaction time were 2, 100 mg/gDS (dry sludge), 0.2A, and 30 min, respectively, with a CST reduction of 43%. Protein and polysaccharide contents in TB-EPS were significantly reduced in the EZVI-NaClO group. Conversely, protein and polysaccharides contents in S-EPS increased, suggesting that EZVI-NaClO treatment could disrupt the EPS. Besides, the viscosity of the treated sludge decreased from 195.4 to 54.9 mPa·S, indicating that sludge fluidity became better. ZEVI-NaClO could enhance sludge dewaterability by destructing protein and polysaccharide structure and improving sludge hydrophobicity.

Molecular Characterization of the Iron-Containing Alcohol Dehydrogenase from the Extremely Thermophilic Bacterium Pseudothermotoga hypogea.

Pseudothermotoga hypogea is an extremely thermophilic bacterium capable of growing at 90 °C and producing ethanol, which is catalyzed by an alcohol dehydrogenase (ADH). The gene encoding P. hypogea ADH (PhADH) was cloned, sequenced and over-expressed. The gene sequence (1164 bp) was obtained by sequencing all fragments of the gene, which were amplified from the genomic DNA. The deduced amino acid sequence showed high identity to iron-containing ADHs from other Thermotoga species and harbored typical iron- and NADP-binding motifs, Asp195His199His268His282 and Gly39Gly40Gly41Ser42, respectively. Structural modeling showed that the N-terminal domain of PhADH contains an α/β-dinucleotide-binding motif and that its C-terminal domain is an α-helix-rich region containing the iron-binding motif. The recombinant PhADH was soluble, active, and thermostable, with a subunit size of 43 ± 1 kDa revealed by SDS-PAGE analyses. The recombinant PhADH (69 ± 2 U/mg) was shown to have similar properties to the native enzyme. The optimal pH values for alcohol oxidation and aldehyde reduction were 11.0 and 8.0, respectively. It was also thermostable, with a half-life of 5 h at 70 °C. The successful expression of the recombinant PhADH in E. coli significantly enhanced the yield of enzyme production and thus will facilitate further investigation of the catalytic mechanisms of iron-containing ADHs.

DNA Adsorption Capabilities of Amine Functionalized Magnetic Cellulose Acetate Butyrate Beads from Aqueous Solution

AbstractIn this work, the magnetic cellulose acetate butyrate beads (mCABs) were prepared and then, their surfaces were modified with [(3‐Aminopropyl) triethoxysilane)] (APTES) solution to generate amine groups (−NH2) as a ligand for DNA adsorption in the aqueous solution. After the surface modification, the −NH2 functionalized mCABs (N−mCABs) were characterized with Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscope (SEM), and energy dispersive X‐ray (EDX) analysis. The optimum pH value of DNA adsorption was observed at pH 4 and at this point, the N−mCABs adsorbed 4.27 mg/g DNA at room temperature (RT). The maximum adsorbed amount of DNA was calculated as 5.24 mg/g and the DNA adsorption was exothermic; furthermore, DNA adsorption was monolayer and the Langmuir adsorption model was more fitted than the Freunclich isotherm model due to the regression coefficient (R2), and the qmax values of the Langmuir model. According to reusability studies, the prepared adsorbent protected its stability and the adsorption capacity after the 5 consecutive adsorption, desorption, and regeneration cycles.

Versatile MXene Gels Assisted by Brief and Low-Strength Centrifugation

HighlightsA low-strength-centrifugation-assisted approach for rapid gelation of Ti3C2Tx MXene with a very low dispersion concentration into multifunctional 3D architectures is developed.On the basis of pH-induced surface termination changes, the MXene gels exhibit reconfigurable internal structures and tunable rheological, tribological, electrochemical, infrared-emissive and photothermal-conversion properties.By adopting a gel with optimized pH value, high lubrication, remarkable capacitance, long-term capacitance retention and high-precision screen- or extrusion-printing into high-resolution anticounterfeiting patterns can be achieved.

Fabrication of green magnetized ferrite biochar nanocomposites from orange peels/MnFe2O4, peanut shells/CuFe2O4, tree twigs/Ni Fe2O4, and wood/CoFe2O4: characterization and application as adsorbents for adsorption/desorption/stability of basic Blue-XGRRL dye with possible mechanisms

Abstract One of the primary sources of water pollution is the wastewater released from textile industry. In the current research, green magnetized ferrite biochar nanocomposites for the purification of basic dye Blue-XGRRL were prepared and characterized. The optimal pH values to attain maximum adsorption for orange peels/MnFe2O4, peanut shells/CuFe2O4, tree twigs/Ni Fe2O4, and wood/CoFe2O4 were noticed in the basic range of 11 (43.5 mg/g), 10 (37.8 mg/g), 10 (31.9 mg/g), and 10 (14.9 mg/g) at 0.05 g/0.05 L at optimal adsorbent dosage correspondingly. The equilibrium observed within 60 min in order of 45.7, 39.9, 33.9, and 18.9 mg/g for adsorbents. The optimal initial dye concentration 100 mg/L was determined for 46.8, 41.4, 37, and 25 mg/g of dye removal utilizing their corresponding adsorbing material at optimal temperature of 30 °C. The data adhered to Langmuir equilibrium and pseudo-second-order kinetic models. Positive Gibbs free energy values led to the conclusion that the process lacks spontaneity. For Blue-XGRRL dye, the maximum desorption (45.4, 41.9, 36.3, and 23.9%) was achieved. For the first two cycles, the removal efficiencies were constant and then marginally declined in third cycle. These green nanocomposites hold promise for effective adsorption in water treatment, signifying their potential as impactful and sustainable solutions.

Biocatalytic enhancement of laccase immobilized on ZnFe2O4 nanoparticles and its application for degradation of textile dyes

Efficient and convenient treatment of industrial dyeing wastewater is of a great significance to guarantee human and animal health. This work presented the enhanced catalytic activity at pH 3.0 of laccase immobilized on amino-functionalized ZnFe2O4 nanoparticles (ZnFe2O4-laccase) and its application for degradation of textile dyes. Due to the existence of a large number of oxygen vacancies on the surface of the ZnFe2O4 nanoparticles, negative ions accumulated on the magnetic carriers, which resulted in a harsh optimal pH value of the ZnFe2O4-laccase. Laccase activity assays revealed that the ZnFe2O4-laccase possessed superior pH and thermal stabilities, excellent reusability, and noticeable organic solvent tolerance. Meanwhile, the ZnFe2O4-laccase presented efficient and sustainable degradation of high concentrations of textile dyes. The initial decoloration efficiencies of malachite green (MG), brilliant green (BG), azophloxine, crystal violet (CV), reactive blue 19 (RB19) and procion red MX-5B were approximately 99.1%, 95.0%, 93.3%, 87.4%, 86.1% and 85.3%, respectively. After 10 consecutive reuses, the degradation rates of the textile dyes still maintained about 98.2%, 92.5%, 83.2%, 81.5%, 79.8% and 65.9%, respectively. The excellent dye degradation properties indicate that the ZnFe2O4-laccase has a technical application in high concentrations of dyestuffs treatment.

Evaluation Of Ph Quality And Water Capacity Of Yogurt Of Etawa Goat Milk (Capra Aegagrus Hircus) With The Addition Of Mangga Golek Fruit Juice

Milk is the product of livestock in the form of white liquid contains nutrients that are very good for humans. This study aims to determine the quality of pH (Hydrogen Potential) and moisture content of Peranakan Etawa (PE) goat milk yogurt with the addition of golek mango juice at different levels. The research was conducted at the Laboratory of the Faculty of Agriculture and Animal Husbandry, Tjut Nyak Dhien University. The research method used a completely randomized design (CRD) with 4 treatments and 5 replications, namely P0, P1, P2 and P3 by testing the pH and moisture content of yogurt.The results showed that the addition of golek mango juice to yogurt gave the same effect on yogurt pH and water content. The optimal pH value, water content and dry matter of etawa peranakan goat milk yogurt in treatment P0 without the addition of golek mango juice with an average pH value of 3.98, water content of 84.4% and dry matter of yogurt of 15.6%. Yogurt dry matter is better in the P0 treatment

A photo-enzyme coupled system for carbon dioxide conversion to solar fuel: The rate-matching and compatibility between photocatalysis and enzyme catalysis

Using reduced nicotinamide adenine dinucleotide (NADH) as cofactor, formate dehydrogenase (FDH) can reversely catalyze CO2 reduction to formic acid. However, the industrialized application of FDH is fairly limited due to its high cost and stoichiometric cofactor consumption. Enzyme immobilization and cofactor regeneration are vital solutions to these problems. Ascribed to the benefits of utilizing a cheap, environmentally friendly, and renewable energy source, photocatalytic NADH regeneration is naturally sustainable and promising. Nonetheless, the rate-matching and compatibility between photocatalysis and enzyme catalysis have not been well revealed. In this study, polyethyleneimine (PEI) modified hollow fiber membrane (HFM) as the enzyme support was in-situ integrated with a visible-light-driven NADH regeneration system using thiophene-modified macroporous graphitic carbon nitride (ATCN-CN) as the catalyst. First, NADH regeneration conditions were regulated to accommodate enzyme catalysis. Then, the photo-enzyme coupled system (PECS) for the sustainable synthesis of formic acid with triethanolamine (TEOA) or H2O as electron donor was constructed, and the influencing factors were investigated. At last, the PECS was compared with other methods as well as a system that used FDH immobilized on silica nanoparticles. The results show that the reaction pH, electron donor, and catalyst concentration have a significant impact on NADH regeneration. For the PECS with TEOA as electron donor, the optimal pH value and photocatalyst concentration for formic acid synthesis are 7.0 and 1.2 mg mL−1, respectively. With the initial addition of 1 mmol L−1 NAD+, a formic acid yield of 35.3% was obtained after 5 h, standing out among the reported values. H2O as a green and low-cost electron donor meets the desire for low-cost photocatalysis. Although the production of formic acid after 5 h was lower in the PECS with H2O as electron donor than in the TEOA system, it was still 14.6 times that of the immobilized enzyme system without cofactor regeneration, and the yield of formic acid could reach 14.8% and 98.3% with 1 or 0.1 mmol L−1 NAD+, validating that current PECS is feasible to a sustainable and green synthesis of solar fuel from CO2.

Renewable-based treatment solution of Reactive Blue 21 dye on fly ash as low-cost and sustainable adsorbent

This study investigated the removal of Reactive Blue 21 (RB 21) dye from aqueous solutions by adsorption, evaluating the waste fly ash (FA). The effects of the parameters, such as initial dye concentration (100–750 mg/L), initial pH (2.0–8.0), adsorbent dose (1.0–4.0 g/L), and temperature (298–323 K) on the adsorption process were investigated. The optimum initial pH value was 2.0 for the highest RB21 dye removal (75.2 mg/g). At optimized conditions (pH 2.0, an adsorbent dosage of 1.0 g/L, a dye concentration of 750 mg/L, and an equilibrium time of 72 h), the highest adsorption capacity was found to be 105.2 mg/g. Moreover, the results of the kinetic studies fitted the pseudo-second-order kinetic model. Equilibrium data were best represented by the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 103.41 mg/g at 323 K. ΔGads0 values were negative and varied from 11.64 to 9.50 kJ/mol in the temperature range of 298–323 K, the values of enthalpy (ΔHadso) and entropy (ΔSadso) of thermodynamics parameters were calculated as 37.62 kJ/mol and 86.67 J/mol K, respectively, indicating that this process was endothermic. Furthermore, the adsorbent costs for powdered activated carbon (PAC) and FA to remove 1 kg of RB 21 dye from aqueous solutions are calculated as 2.52 U.S. $ and 0.34 U.S. $, respectively. It is seen that the cost of FA is approximately 7.4 times lower than PAC. The results showed that FA, a low-cost industrial waste, was promising for the adsorption of RB 21 from aqueous solutions.

Evaluation of extracellular alkaline proteases from Bacillus for environmentally friendly detergent additives

Growing demand for environmentally friendly and sustainable enzyme solutions drives markets for alkaline proteases across various industries. Alkaline proteases produced by different Bacillus strains exhibit unique properties and versatility. Production of alkaline proteases from Bacillus amyloliquefaciens TBRC 2902, B. siamensis TBRC 1180, B. subtilis TBRC 6663, and B. velezensis TBRC 7773 was optimized by adjusting production media, considering carbon and nitrogen sources to enhance extracellular enzyme activities. Optimized extracellular protease activity was achieved using tapioca starch for TBRC 2902 and TBRC 1180, and soluble starch for TBRC 7773, while both carbon sources were optimal for TBRC 6663. Skim milk was an equally effective nitrogen source for TBRC 2902, TBRC 1180, and TBRC 7773, whereas soytone was as effective as yeast extract for TBRC 6663. Inorganic nitrogen sources, such as diammonium hydrogen phosphate for TBRC 2902 and potassium nitrate for TBRC 1180, enhanced alkaline protease activity by 10-20%. The protease from B. siamensis TBRC 1180 exhibited optimal pH and temperature values of 9.0 and 60°C, respectively, while the others had optimal values of 8.0 and 50°C. All enzymes tolerated non-ionic surfactants, retaining over 40% activity after 24 hours exposure to Triton X-100, Tween-20, and Tween-80, indicating their potential as detergent additives.

Study on adsorption of methyl orange by waste tea

The adsorption effect of waste tea leaf on dye methyl orange was studied. The tea after decolorization for 6 h was modified with potassium permanganate, and then the adsorption properties of unmodified and potassium permanganate modified tea to methyl orange were studied. The influence of the optimal pH value, dosage of unmodified and modified tea, initial concentration of methyl orange, adsorption temperature and contact time variables of methyl orange and tea powder on the adsorption performance was obtained in the experiments. Under the optimized conditions, the maximum adsorption rate of potassium permanganate-modified tea leaves was 99.82 %, and the maximum adsorption capacity was 3.9928 mg/g. The kinetics, thermodynamics and adsorption properties of methyl orange by KMnO4 activated tea and unmodified teas were studied. The adsorption kinetics results showed that the adsorption was in accordance with the pseudo-second-order kinetic equation. The adsorption thermodynamics results showed that the adsorption process was exothermic and the entropy decreased. The research results of adsorption isotherms showed that the adsorption process was in accordance with the Freundlich adsorption isotherm. Scanning electron microscopy, X-ray diffraction and infrared spectroscopy were used to characterize KMnO4 activated tea powder samples. This method can adsorb methyl orange, reduce the concentration of methyl orange in wastewater and the damage to the environment.

Reduction of sulfur and ash contents from low-rank coal

This research attempted to reduce sulfur and ash content for enhanced coal recovery by the froth flotation technique. Dukki district (Pakistan) coal was upgraded using a flotation technique followed by acid leaching. Tests on flotation concentrate were carried out to improve the grade of coal further. Tests were carried out to investigate and determine the effect of critical parameters like particle size, pH, and pulp density on reducing ash and sulfur content from coal. The particle size was observed to have the most significant role in coal ash and sulfur reduction, followed by the pH, and pulp density, respectively. The optimum particle size, pH, and pulp density values were 74 μm, 9 and 10%, respectively. The results from the flotation study on a laboratory scale at optimized conditions were a 54.1% increase in total carbon, a 42.12% reduction in ash, and a 38.32% reduction in sulfur. Final ash and sulphur contents in clean coal were 15.2% and 1.65%, respectively. Thus, clean coal can preferably be used in power plants and the cement industry in the country.

Photocatalytic Degradation of Heavy Metals Cd, Cu, Fe and Pb Using ZnO-Zeolite Nanocomposite

Heavy metals are the main pollutant substances in the environment. Heavy metals are a type of metal with high density and are very dangerous to living organisms, especially humans. Living organisms can adsorb the bioaccumulative and sedimentation of heavy metals that settle in water. Some compounds which found in wastewater including Cadmium (Cd), Copper (Cu), Iron (Fe), and Lead (Pb). These heavy metals cannot naturally degrade, additional processing is required before it being released into the environment. To prevent environmental pollution impacts, wastewater containing heavy metals must be handled properly and optimally. One method that can be applied for wastewater treatment is degradation by photocatalysis, utilizing the assistance of light. This research is to investigate the effect of pH and irradiation time on the degradation of Cd (cadmium), Cu (Copper), Fe (Iron), and Pb (Lead) heavy metals. To enhance the photocatalytic activity, the synthesis of ZnO-Zeolite nanocomposites was conducted. The ZnO-Zeolite nanocomposites produced were analyzed by SEM-EDX and XRD. The utilization of ZnO-Zeolite nanocomposites is deemed effective in reducing heavy metal concentrations. The degradation with Ultraviolet (UV) light exposure runs within 15-120 minutes with pH variation between 4-8. The degradation of heavy metal runs at 60 minutes and 120 minutes showing an optimum percentage removal of metals approaching 100%. The optimum pH values for Cd, Cu, Fe, and Pb are pH 8, pH 7, pH 6, and pH 8, respectively. The sequential metal degradation percentages are 98.96%, 95.43%, 96.07%, and 95.53%, respectively.

Simplification of the pretreatment method for phosphate oxygen isotope measurement in phosphogypsum leachate

The stacking of phosphogypsum has caused considerable phosphorus pollution in water bodies near phosphogypsum yards through surface runoff and underground infiltration. The phosphate oxygen isotope (δ18Op) tracing method has served as a valuable tool for tracing phosphorus pollution in water. However, the existing δ18Op enrichment and purification methods are complex, costly, and inefficient for phosphate recovery, particularly for phosphogypsum leachate with complex compositions. Herein, a simplified and optimized pretreatment method for δ18Op measurement in phosphogypsum leachate was developed. Zirconium/polyvinyl alcohol (Zr/PVA) gel beads showed good selectivity for phosphate enrichment from water at different initial phosphate concentrations with appropriate Zr/PVA dosage. The optimal enrichment pH value was <7, and the concentrated phosphate on the Zr/PVA gel beads could be effectively eluted in an alkaline environment. Compared with the traditional Fe or Mg coprecipitation enrichment methods, impurities in the solution showed no obvious adverse effects on the phosphate enrichment process. Further, the phosphate solution eluted from the Zr/PVA gel beads was purified by a simple adjustment of the pH instead of cation exchange in the traditional purification process. Magnesium ions in the solution could be completely removed when the pH ranged from 3.17 to 6.15, and the phosphate recovery rate could reach 98.66% when the eluent pH was 5.02. Fourier-transform infrared spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy revealed that similar to traditional pretreatment method, the proposed method can obtain high-purity Ag3PO4 solids for δ18OP measurement and no isotope fractionation of δ18OP was observed. Therefore, this study provides a promising and reliable pretreatment method for δ18OP measurement, especially in complex phosphogypsum leachate.

Fabrication and performance evaluation of rGO-PANI supported NiP/TMD based biosensors for electrochemical detection of dopamine

In this study, we present a novel approach for electrochemical sensing of DPA through the development of a unique electrode. It (WM-GP@NiMoP) composed of a mixed transition metal dichalcogenides (WS2-MoS2) supported by rGO and PANI, embedded via a facile electroless NiMoP plating technique. To evaluate the physico-chemical properties of the coatings, including phase analysis (X-Ray diffraction studies), morphology (Filed emission scanning electron microscopy), topology (Atomic force microscopy) and to assess the catalytic activity of the electrode for DPA sensing. The sensing behavior under various operating conditions, encompassing scan rate and pH of the analyte. The durability and performance evaluation were conducted to identify the consistent performance at an optimal pH value of 7 and it shown remarkable selective sensitivity and suppression of glucose and ascorbic acid interferences. The k0 values for the reversible electrode systems like dopamine was reasonable (5.3 ×10−10 cm/s) for the respective oxidation reactions. The CV analysis envisages the sensing potential of electrode towards DPA oxidation due to synergistic effect between PANI and rGO to MTMD on NiMoP coated electrodes. The work highlights the remarkable sensing capabilities of the WM-GP12 @NiMoP electrode in the field of electrochemical detection of DPA. Its exceptional sensitivity towards sensing of DPA establishes it as a significant advancement in electrochemical sensing technology.

Use of Pulsed Currents with Long Off-Times to Increase Proprieties of Trivalent Chromium Based Deposits

Health authorities directives, such as the REACH European regulation, are particularly severe with compounds such as hexavalent chromium salts, toxic for both humans and the environment. As a result, trivalent chromium salts have been extensively studied [1] as a promising alternative to the hard chromium process. However, electrolytes containing trivalent chromium ions present challenges, as the proprieties of the deposits are not identical, although they are getting closer. One difference is the high carbon and oxygen contents in trivalent chromium plating [2], mainly caused by the incorporation of organic and hydroxide species, the latest as a result of the increase of the surface pH. This is a direct consequence of the significant current used to reduce protons during the plating process.There are several approaches to limit pH increase [3], such as adjusting the temperature or the bulk pH, or adding specific chemical compounds. This study explores the use of pulsed currents. An initial research did not be able to define pulse parameters (e.g., current density, on and off-times) that could selectively reduce chromium without also reducing hydrogen [4], which can occur with other electrolytes. We consequently decided to focused on near-surface phenomena by measuring local pH [5]. This was possible by implementating a micro-electrode to a few dozen of µm from the interface. Thus, a critical parameter was identified : resting time (toff). It was found that extending off-times maintained optimal pH values at the interface during deposition. The effect of these pulse sequences was evaluated, among other parameters, on internal stresses formed during deposition and the relaxation phase using a device developed at the University of Houston (material science program and electrical and computer engineering) [6]. [1] P. Benaben, « An Overview of Hard Chromium Plating Using Trivalent Chromium Solutions », Plating and Surface Finishing, p. 8, 2011. [2] A. Baral et R. Engelken, « Modeling, Optimization, and Comparative Analysis of Trivalent Chromium Electrodeposition from Aqueous Glycine and Formic Acid Baths », J. Electrochem. Soc., vol. 152, no 7, p. C504, 2005, doi: 10.1149/1.1933688. [3] J. Ji, W. C. Cooper, D. B. Dreisinger, et E. Peters, « Surface pH measurements during nickel electrodeposition », J Appl Electrochem, vol. 25, no 7, p. 642-650, juill. 1995, doi: 10.1007/BF00241925. [4] J. Rolet, « Influence de la forme de l’onde de polarisation sur la microstructure et les propriétés de revêtements électrolytiques élaborés à base de chrome trivalent », PhD thesis, Bourgogne Franche-Comté, 2017. [5] M. Marcelet et al., « Influence of Pulse-Current Parameters on pH Measured By Local Method », Meet. Abstr., vol. MA2019-02, no 21, p. 1046, sept. 2019, doi: 10.1149/MA2019-02/21/1046. [6] K. Ahmadi et al., « Crack Free Cr Coatings from Cr 3+ Electrolyte », J. Electrochem. Soc., vol. 169, no 1, p. 012504, janv. 2022, doi: 10.1149/1945-7111/ac4bfa.

The Influence of Solution Concentration and pH for Removal Indigo Carmine using Banana Stem as a Biosorbent

The textile industry is one sector that generates effluent containing a significant quantity of pollutants, including dyes, and thus has an effect on the environment. Synthetic dyes, which are toxic and difficult to degrade, are utilized extensively in the textile industry. Therefore, a new study utilizes banana stems as a cost-effective biosorbent to remove indigo carmine dye. This research aims to investigate the use of banana stem waste as a bisorobent in batch method to adsorption indigo carmine dye. The optimal concentration and pH values are 2 and 900 mg/L, respectively. The interaction between the indigo carmine dye and the banana stems is suggested by the FTIR analysis. The solution's indigo carmine dye may be adsorbed by banana stem.

Mechanisms and factors affecting the removal of minocycline from aqueous solutions using graphene-modified resorcinol formaldehyde aerogels

In recent years, concerns about the presence of pharmaceutical compounds in wastewater have increased. Various types of residues of tetracycline family antibiotic compounds, which are widely used, are found in environmental waters in relatively low and persistent concentrations, adversely affecting human health and the environment. In this study, a resorcinol formaldehyde (RF) aerogel was prepared using the sol–gel method at resorcinol/catalyst ratio of 400 and resorcinol/water ratio of 2 and drying at ambient pressure for removing antibiotics like minocycline. Next, RF aerogel was modified with graphene and to increase the specific surface area and porosity of the modified sample and to form the graphene plates without compromising the interconnected porous three-dimensional structure of the aerogel. Also, the pores were designed according to the size of the minocycline particles on the meso- and macro-scale, which bestowed the modified sample the ability to remove a significant amount of the minocycline antibiotic from the aqueous solution. The removal percentage of the antibiotic obtained by UV–vis spectroscopy. Ultimately, the performance of prepared aerogels was investigated under various conditions, including adsorbent doses (4–10 mg), solution pHs (2–12), contact times of the adsorbent with the adsorbate (3–24 h), and initial concentration of antibiotic (40–100 mg/l). The results from the BET test demonstrated that the surface area of the resorcinol formaldehyde aerogel sample, which included 1 wt% graphene (RF-G1), exhibited an augmentation in comparison to the surface area of the pure aerogel. Additionally, it was noted that the removal percentage of minocycline antibiotic for both the unmodified and altered samples was 71.6% and 92.1% at the optimal pH values of 4 and 6, respectively. The adsorption capacity of pure and modified aerogel for the minocycline antibiotic was 358 and 460.5 mg/g, respectively. The adsorption data for the modified aerogel was studied by the pseudo-second-order model and the results obtained from the samples for antibiotic adsorption with this model revealed a favorable fit, which indicated that the chemical adsorption in the rapid adsorption of the antibiotic by the modified aerogel had occurred.

Utilization of Silver Nanoparticles as Adsorbent of Methylene Blue

This study has successfully synthesized silver nanoparticles (Ag NPs) using banana stem extract as the bioreductor and reported its application in adsorption of methylene blue (MB). Adsorption of MB was tested under ultraviolet light by varying pH solution values (3, 4, 5, 7, 9, 10, and 11), irradiation times (0,5, 1, 2, 3, 4, 5 hours), and MB concentrations (50, 100, 150, and 200 ppm) to determine their optimum values. The results revealed that the optimum pH value and irradiation time were at 9 and 1 hour, demonstrating the highest deconcentration percentage (%D) of 89.19% and 94.58%, respectively. The %D of MB dye by samples with concentrations of 50, 100, 150, and 200 ppm were 86.294%, 78.416%, 69.366%, and 66.638%, respectively, with an average of %D of 75.189%. The least degraded MB was 90.643 mg, obtained at 50 ppm. Meanwhile, the most degraded MB was 280.181 mg, attained at 200 ppm. The average concentration of degraded MB was 188.538 mg/gr.