Dye Concentration Research Articles

Investigating and correlating the photocatalytic activity of synthesised strontium titanate nanopowder with calcination temperature

In this study, SrTiO3 nanoparticles were synthesised in high yield using a simple and low-cost method, followed by calcination. The effect of the calcination temperature in the range from 700 to 1100 °C on the morphology, phase structure, crystallite size, and photocatalytic activity of SrTiO3 nanoparticles was investigated. Analysis of the morphology and structure of the synthesised samples revealed an increase in the average particle size from 70.4 to 361.72 nm as well as crystallite growth with increasing calcination temperature (from 800 to 1100 °C), likely due to the fusion of smaller crystallites into larger ones. A possible pathway for the growth mechanism of strontium titanate grains was also proposed. The SrTiO3 sample calcined at 800 °C exhibited the highest methylene blue (MB) photodegradation efficiency, achieving 100 % degradation within 30 min of irradiation. The pseudo-first-order reaction rate constant k for this sample was determined to be 0.156 min−1, which is almost 1.8 and 14.19 times higher compared to those of commercial P25 and SrTiO3, respectively. The analysis indicated that the high photoactivity of this sample was due to its high crystallinity, relatively small particle size, and optimal light absorption, which enhanced the separation and transport of the photogenerated charges and increased the number of active sites, thereby positively affecting the photocatalytic properties. Additionally, the effects of the initial dye concentration and amount of photocatalyst loaded on the photodegradation efficiency were investigated.

Synthesis, Magnetic, and Photocatalytic Activity of Polypyrrole-Based TiO2–Fe Catalyst for Wastewater Treatment

The primary aim of this study is to investigate the degradation efficacy of the Ppy/TiO2-Fe photocatalyst for MB dye in an aqueous solution. Firstly, the direct addition of TiO2 and Fe was done to prepare Ppy/TiO2-Fe photocatalyst. Fourier transformation infrared spectroscopy, XRD, SEM, BET surface area analysis, and magnetization tests established the formation of the Ppy/TiO2-Fe photocatalyst. The crystallite sizes of TiO2, Fe-TiO2, and Ppy/TiO2-Fe photocatalyst were estimated to be 24.99 nm, 21.94 nm, and 21.84 nm, respectively. For the synthesis confirmation, the FTIR spectrum confirmed the existence of Ti-O, Fe-O, and Ppy-related bonds. While comparing the SEM images, the impact of polypyrrole on the particle shape was observed with less aggregation and increased surface roughness. The VSM analysis revealed that incorporating polypyrrole (Ppy) into Fe-TiO2 significantly enhances its magnetic properties, with Ppy/TiO2-Fe exhibiting superparamagnetic behavior, characterized by a higher saturation magnetization (Ms) of 33.11 emu/g and a lower coercivity (Hc) of 0.160 Oe, compared to Fe-TiO2’s Ms of 1.09 emu/g and Hc of 341.39 Oe. The N2 sorption desorption, with a specific surface area of 2.25 × 102 m2/g, is beneficial for photocatalytic activity. The concentration of dye, amount of catalyst, pH, and temperature were studied to evaluate the photocatalytic efficiency of the synthesized Ppy/TiO2-Fe photocatalyst under different conditions. The findings revealed a degradation efficiency of 91.92%. The degradation rate reached 91.92% under optimal conditions within 120 min and could be fitted well by first-order kinetics. The photocatalytic efficiency was also evaluated for the scavenger, and the concentration of H2O2 and the reusability of the catalyst were demonstrated. Based on the observed results, the Ppy/TiO2-Fe photocatalyst could be applied more effectively and efficiently to photocatalytic degradation of organic dyes in wastewater treatment.

A facile and green synthesis of corn cob-based graphene oxide and its modification with corn cob-K2CO3 for efficient removal of methylene blue dye: Adsorption mechanism, isotherm, and kinetic studies

In recent years, the treatment of synthetic dyes has become an environmental concern. In this study, a single step calcination process was used to develop the inventive, simple, and inexpensive adsorbent CC-GO/CC-K2CO3 composite. The composite was employed for the treatment of methylene blue (MB), a cationic dye. Several characterization methods including powder XRD, FTIR, XPS, BET, FESEM, EDX, Raman, and HRTEM techniques were utilized for the analysis of the composite. The surface area and mean pore diameter of CC-GO/CC-K2CO3 were 32.651 m2 g−1 and 3.71 nm, respectively. The adsorption experiment showed that optimal parameters for the removal of MB dye are at an adsorbent dose of 60 mg, initial dye concentration of 80 mg/L, contact time of 150 min, and pH value of 12 at room temperature. Under optimized conditions, CC-GO evidences a removal efficiency of 70.34 ± 1.36 % while after incorporation with CC-K2CO3 the removal capacity sharply increases up to 98.10 ± 0.4 %. Kinetic and isotherm models were used to analyze the removal rate constant and equilibrium adsorption capacity under various adsorption environments. The adsorption study was found to follow the models of pseudo-second order kinetic and Freundlich isotherm. The CC-GO/CC-K2CO3 composite has the maximum adsorption capacity (MAC) of 160.77 mg/g established by the Langmuir isotherm. The prepared composite has demonstrated the capacity to be recycled up to three times with a gradual decrease in its adsorption behavior, exhibiting removal efficiency of 61.66 ± 2.04 %.A cost estimation study of the composite was also performed to assess its cost effectiveness.

Degradation of Nile Blue by Photocatalytic, Ultrasonic, Fenton, and Fenton-like Oxidation Processes

The aim of this study is to investigate new catalytic systems for the degradation of a dye that has been classified as first-degree toxic pollutant. Advanced oxidation process such as photocatalytic oxidation, ultrasonic oxidation, Fenton, and Fenton-like constitute a promising technology for the treatment of wastewater containing organic compounds. Waste effluents from textile industries are a major source of water pollution. These wastewaters contain dyes, which have high toxicity and low biodegradability. In this study, degradation of Nile Blue (NB), an azo dye, was studied using the photocatalytic oxidation (TiO2 and silver-loaded TiO2 (Ag-TiO2) as catalyst), ultrasonic oxidation, Fenton (Fe(II)/H2O2), and Fenton-like (Cu(II)/H2O2, V(IV)/H2O2) processes. It was found that the photocatalytic degradation of NB increased with decreasing pH, and the degradation rate also increased in the presence of TiO2/UV compared to UV irradiation alone. In addition, Ag loading on TiO2 dramatically reduced the degradation time. The ultrasonic degradation of NB was also studied using different initial dye concentrations at different pH values and amplitudes. Concentrations of Fe(II), Cu(II), V(IV) and H2O2 on degradation ratio were investigated. It is found that Fe(II) ion is more effective than Cu(II) and V(IV) ions in the degradation of NB.

Design of a Nickel mixed-ligand coordination compound for the removal of pollutant dye, methyl orange, from water

We report the uptake of methyl orange (MO) dye from aqueous solution by a synthesized Ni(II) complex. Characterization of the complex was achieved by powder X-ray diffraction (PXRD) analysis, Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, and Scanning Electron Microscopy (SEM). BET surface area values were observed to be 252.450 m2 g−1 before adsorption and 242.260 m2 g−1 after adsorption. SEM micrographs showed a change in the morphology of the compound after adsorption. Adsorption experiments carried out at different conditions of dye concentration, pH of dye solution, contact time, dosage and temperature showed that the adsorption data best fits the Freundlich Isotherm with an R2 value of 0.9532 and adsorption process followed the pseudo-second-order kinetics equation (R2 = 0.9898).

Kinetics Analysis of Crystal Violet Adsorption from Aqueous Solution onto Flamboyant Pod Biochar

The increasing presence of presistent synthetic dyes, like crystal violet (CV), in wastewater poses a significant threat to aquatic ecosystems and human health due to its genotoxicity and carcinogenicity. Biochar derived from agricultural waste offers a promising, cost-effective, and eco-friendly approach for dye removal. This study explores the potential of flamboyant pod biochar (FPB) as a novel and sustainable adsorbent for CV removal. FPB offers a unique advantage as it utilizes readily available flamboyant pod waste, promoting waste valorization and a cost-effective approach. FPB was synthesized through a simple process involving milling, sun-drying, and pyrolyzing flamboyant pod waste at 300 °C. Batch adsorption experiments were conducted to evaluate the influence of contact time and initial dye concentration on removal efficiency. Kinetic modeling using pseudo-first-order and pseudo-second-order models explored the underlying mechanisms governing the adsorption process. The pseudo-second-order kinetic model exhibited a superior fit (R² > 0.87) compared to the pseudo-first-order model, suggesting a chemisorption mechanism governing the adsorption process. These findings demonstrate the potential of FPB as a low-cost, sustainable adsorbent for CV removal from wastewater.

Preparation of new green poly (amino amide) based on cellulose nanoparticles for adsorption of Congo red and its adaptive neuro-fuzzy modeling

In this study, a novel green poly(amino amide) nanoparticle based on cellulose nanoparticles (Cell-PAMN) was developed for the efficient adsorption of Congo Red dye. Cellulose nanocrystals obtained from acid hydrolysis of cotton linter were functionalized via Oxa-Michael addition of acrylamide on their surface hydroxyl groups, followed by transamidation with ethylenediamine. The resulting nanoparticles were characterized using FT-IR spectroscopy, SEM, and X-ray diffraction techniques. The as-prepared Cell-PAMN exhibited considerably higher adsorption capacity compared to unmodified cellulose nanoparticles due to the presence of amino and amide functional groups. The adsorption kinetics and the effects of parameters such as contact time and initial dye concentration on the adsorption capacity were investigated. An adaptive Neuro-Fuzzy model was used to study the efficiency of dye removal, accurately predicted the adsorption behavior of Cell-PAMN. The kinetic study results showed that the adsorption process followed a pseudo-second-order kinetic model, with a maximum adsorption capacity of around 40 mg/g. The results demonstrated the potential of the synthesized material for the removal of Congo Red from aqueous solutions, highlighting its applicability in wastewater treatment. This research contributes to the development of sustainable and eco-friendly materials for environmental remediation applications.

Sunlight-Driven Photodegradation of RB49 Dye Using TiO2-P25 and TiO2-UV100: Performance Comparison

By combining measurements of photocatalysis under solar irradiation with measurements of total organic carbon, we have compared the performance of two TiO2-based photocatalysts in the photodegradation of the dye Reactive Blue 49 (RB49). TiO2-P25 and TiO2-UV100 commercial photocatalysts were tested within a concentration ranging from 0.5 to 4 g/L. The dye solution concentration was varied from 10 to 50 mg/L and its pH was increased from 3 to 9. Extensive characterization of the photocatalysts was performed using Fourier-transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. TiO2-UV100 proved to be more active in adsorbing RB49 dye than TiO2-P25. At low dye concentrations, the adsorption equilibrium is reached in 15 min. This time increases to 1 h at higher concentrations. The photocatalytic degradation of aqueous RB49 under sunlight was monitored by UV-Vis spectrophotometry. The apparent rate constant of dye photodegradation with TiO2-UV100 is twice that of TiO2-P25. The total organic carbon (TOC) analysis showed a removal of around 98% with TiO2-UV100 and only 85% with TiO2-P25 after 3 h of solar irradiation. Over five photocatalytic cycles of 3 h, TiO2-UV100 maintained a more stable and higher efficient photocatalytic performance. All our results converge toward a better photocatalytic performance of TiO2-UV100 for the photodegradation of RB49 dye and indicate that the most decisive factor is its greater capacity to adsorb the pollutant.

A-056 Investigating Iodine Contrast Contamination in Cortisol and Aldosterone Samples

Abstract Background Primary aldosteronism (PA) is a condition characterized by hypertension resulting from excess secretion of aldosterone. PA caused by a unilateral aldosterone-producing adenoma can be treated with adrenalectomy but requires diagnosis by adrenal vein sampling (AVS). In this procedure, intravenous cosyntropin is administered to stimulate adrenal cortical secretion, followed by obtaining samples from the right and left adrenal veins and IVC. Laterization index is calculated by obtaining the aldosterone:cortisol ratio for each side, with a ratio cutoff ≥3 is used for confirmation. Iodinated contrast media facilitates visualization of catheter positioning during AVS and sometimes results in contamination of samples, evidenced by abnormal gel separator flotation (i.e. gel above plasma). This study had two aims: 1) to determine at what concentration contrast dye causes gel flotation and 2) discern whether contrast media interferes with our cortisol or aldosterone assays. Methods Gel flotation studies were performed by spiking pooled plasma samples with iohexol contrast media (Omnipaque 240, GE Healthcare) at concentrations ranging from 3%-10% v/v and aliquoting into fresh lithium heparin plasma separator tubes (BD, PSTs). Samples were then centrifuged and visually inspected for abnormal gel flotation. Contrast interference studies were performed using three pools of low (5 µg/dL), medium, (30 µg/dL), and high (55 µg/dL) cortisol concentrations. Sample pools were diluted with 20% contrast media or saline (control) and subsequently mixed at different ratios to create a range of dye concentrations (0.5%-18% v/v). Each mixture was assayed in triplicate for cortisol and aldosterone on a cobas e602 (Roche Diagnostics) and LIAISON XL (DiaSorin) immunoanalyzer, respectively. The total allowable error (TEa) was ±0.4 μg/dL or ±20% for cortisol and ±2 ng/dL or ±20% for aldosterone. Results Flotation of the gel separator was observed at a dye concentration of 4.5% v/v and greater. For the cortisol interference study, the bias was <5% for the three pools at all contrast media concentrations. Aldosterone was also measured in these pools, as bias could affect ratios calculated for PA. Aldosterone interference occurred at contrast dye concentrations ranging from 12%-20% v/v. An average positive bias of 34% was observed in aldosterone samples spiked with contrast media relative to the saline control. Compared to sample pool controls without added saline or dye, measurements for cortisol and aldosterone were 19%-22% and 16-25% lower in media- and saline-spiked samples (20% v/v), respectively, indicating a logical dilution effect. Conclusions Contrast dye contamination of AVS specimens can cause gel flotation in lithium heparin PSTs, preventing their analysis. The presence of contrast media at certain concentrations interfered with the DiaSorin aldosterone assay, leading to falsely elevated results. No cortisol assay interference occurred in the presence of contrast media but results were falsely decreased due to sample dilution. Samples collected during AVS may be contaminated with contrast dye causing gel flotation to occur. This is indicative of a minimum contrast media concentration of 4.5% v/v. Aldosterone:cortisol ratios may be inaccurate due to the positive aldosterone immunoassay bias with contrast media contamination. Care should be taken when reporting and interpreting AVS results with suspected contamination.

Aggregation Behavior of CHR-bis(BODIPY) Bichromophores in THF-water Mixtures: Effect of Linking Positions and Aryl-spacer Substituents.

Aggregation-caused quenching effect (ACQ) greatly limits the practical use of many organic luminophores in biomedicine, optics and electronics. The comparative analysis of aggregation characteristics of CHR-bis(BODIPY) bichromophores 1-6 with R = H, Ph, MeOPh and various linking positions (α,α-; α,β-; β,β- and β',β'-) in THF-water mixtures with different water fractions or dye concentrations is first presented in this article. Both the linking style 1-4 and the arylation of the spacer with phenyl (Ph-) 5 or methoxyphenyl (MeOPh-) 6 substituents strongly affect the formation of luminophore aggregated forms in binary THF-water mixtures. The α,α-and β,β-isomers (1 and 3) form non-fluorescent H-type aggregates in THF-water mixtures with fw > 70%. The α,β-; β',β'-isomers (2, 4) and the MeOPh-substituted β,β-bichromophore 6 are characterized by predominant formation fluorescent aggregates. All bichromophores are characterized by the presence of residual amounts of non-aggregated forms in binary mixtures with maximum water content. The results are useful for controlling the aggregation behavior and spectral characteristics of CHR-bis(BODIPY) bichromophores in aqueous-organic media, which is important in the development of biomarkers and PDT agents.

Bioremediation of textile wastewater using Bacillus cereus isolated from refinery site: Comparative analysis of free and immobilized cells systems

The textile industries consume a considerable amount of freshwater and discharge untreated or semi-treated pollutants to the environment. Azo dyes, generally employed in textile manufacturing industries, have a hazardous impact on the ecosystem. Incomplete treatment of wastewater containing azo dyes discharges into the aquatic system, which has recalcitrant and toxic properties. Hence, the need for cost-effective and high-performing technologies is essential. In this direction, bacterial degradation is considered an economically viable and efficient technique for the treatment of Active blue (AB) dye. Polyurethane foam (PUF) is a low-cost and hydrophilic material with a microporous structure, which offers an excellent surface-to-volume ratio. Hence, PUF was preferred for the immobilization of isolated bacterial species. For this, a dye-degrading gram-positive bacteria namely Bacillus cereus GS2 IIT (BHU) was isolated from the petroleum sludge. A comparative analysis between free and immobilized cell systems was carried out by varying the process parameters, i.e., batch time, pH, temperature, glucose concentration, and initial AB dye concentration. The corresponding optimum conditions were found to be 6.0 days, 6.5, 30 °C, 1.0 g/L, and 50 mg/L, respectively. The immobilized cell system exceeds the dye removal efficiency (RE) by 10. 7 % compared to the free cell system. The packed bed bioreactor could be able to deliver 98.56 % of dye removal at an inlet loading rate of 30 mg/L d and 50 mg/L of initial dye concentration.

Process optimization of victoria blue dye removal using polypyrrole-encapsulated zirconium oxide: Mechanistic pathway and economic assessment

In this study, an organometallic composite, namely a polypyrrole-encapsulated zirconium oxide (ZrO2/PPy) nanocomposite, was developed and used to eliminate Victoria blue dye (VB) from water system. Specific surface area of the ZrO2/PPy obtained from BET study was observed to be 61.822 m2/g. Solution pH of 7.0, ZrO2/PPy nanocomposite dose of 0.8 g/L, sonication period of 40 min and initial VB dye concentration of 50 mg/L were chosen as optimal test parameters, at which 86.23 (±1.15) % of VB dye elimination was observed. The VB dye uptake process follows pseudo-second-order kinetic model and Langmuir isotherm model, with the later providing the maximum VB dye adsorption capacity of ZrO2/PPy nanocomposite as 238.09 mg/g. Thermodynamics study suggests the spontaneous (ΔGo< 0) and endothermic (ΔHo> 0) nature of the adsorption study. Food processing wastewater causes maximum hindrance (∼20 (±0.90) % −25 (±1.03) %) in the VB dye uptake process while the presence of phosphate (PO43−) ions can create highest interference (∼17 (±0.93) % −19 (±1.08) %) in the VB dye uptake process. At the optimum test parameter values (adsorbent dose: 1.3 g/L, initial VB dye concentration: 20 mg/L, sonication period: 70 min) as suggested by response surface methodology (RSM), maximum VB dye elimination of ∼96 % was observed. Electrostatic attraction, π–π interaction and hydrogen bond formation are amongst the major uptake mechanisms. Regeneration study indicates ∼19 (±1.36) % of decrease in VB dye elimination (%) after fifth cycle of reuse. The lab scale and industrial scale fabrication expense of 1.0 kg of ZrO2/PPy nanocomposite were obtained as 75.74 and 22.20 USD, respectively. The findings of this study suggest the potential of ZrO2/PPy nanocomposite as an effective and economically viable adsorbent to eliminate VB dye from wastewater.

Eco-friendly fabrication of ZnO-TiO2-rGO nanocomposite for efficient adsorption-assisted organic dyes elimination

The growing interest in combining the photocatalytic properties of semiconductors like ZnO and TiO2 with the superior electron conduction capabilities of graphene has resulted in the successful synthesis of in-situ reduced graphene oxide (rGO) supported ZnO-TiO2 nanostructures through a simple microwave-assisted synthesis method. X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–visible spectroscopy (UV–vis), and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterize structural, morphological and optical properties as well as surface functional groups of the synthesized products. The XRD measurements of our synthesized samples confirm both structural crystallinity and phase purity, while the FTIR analysis verifies the complete reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The synthesized ternary nanocomposite ZnO-TiO2-rGO exhibited a remarkable 100 % adsorption-assisted removal efficiency for 20 mg/L methylene blue (MB) dye under ultraviolet light illumination within 120 min, along with a 56 % dye adsorption removal efficiency in the same time interval. In comparison, pure ZnO showed 0 % adsorption and only 31 % photocatalytic efficiency at the similar condition. Remarkably, the ZnO-TiO2-rGO nanocomposite exhibited exceptional photocatalytic activity mediated by adsorption, achieving complete degradation of MB dye within 5 min under sunlight irradiation. The photocatalytic efficiency and dye adsorption capacity were found to be significantly lower for the anionic dye methyl orange (MO) compared to the cationic MB dye. The study thoroughly investigated the influence of catalyst dose and initial dye concentration on photodegradation. The proposed mechanism indicates that the extensive surface area and numerous active sites on the rGO promote adsorption, which is then followed by degradation through the metal oxides. Overall, the results unveil that the microwave-assisted synthesis of ZnO-TiO2-rGO nanocomposite is a promising and environmentally friendly approach for efficiently degrading dyes from contaminated wastewater using both UV light and natural sunlight irradiation.

Comparative study of photo catalytic activity of Tinospora Cordifolia derived nanoparticles for degradation of indigo carmine

Plant-mediated synthesis of nanoparticles has emerged as an important field in synthesis of nanoparticles (NPs) as fewer chemicals are being used, method is cost-effective and also fulfils principles of green chemistry. Due to the rapid growth of industries in recent times, there has been an increase in concentration of dyes in water, which causes problems and affects human and animal’s health. Moreover, nanoparticles has emerged as an effective solution for dye degradation due to their effective catalytic activity. In the current work, we carried out a comparative study on Tinospora Cordifolia, derived oxide nanoparticles for degrading Indigo Carmine. The characterization of formed particles have been done by techniques like XRD, SEM, FTIR and EDX. The effectiveness of the synthesized nanoparticles as photo catalyst in removing indigo carmine was assessed by emphasizing on important aspects such as amount of catalyst, concentration of dye, and the pH. The results showed SnO2 nanoparticles exhibited superior degrading activity compared to CuO. The optimal dose for SnO2 NPs was 0.25 g/L, while for CuO, it was 0.50 g/L. When pH was altered, it was observed that acidic environment exhibited superior breakdown ability. The optimal degradation capability was observed at dye concentration of 40 parts per million (ppm).

Selection of the Optimal Concentration of Nitro Blue Tetrazolium Dye in Polyvinyl Alcohol Film for Diagnostic Radiology

Ensuring the limited exposure of both patients and medical professionals to radiation during examinations is paramount. One effective approach is the utilization of a film dosimeter that is not only efficient but also easy to carry. In this research, we employed polyvinyl alcohol/nitro blue tetrazolium (PVA/NBT) with varying concentrations of NBT dye (ranging from 0.015 to 0.3 g) to identify the most optimal concentration. These films were subjected to low doses of gamma rays (8, 25, 55 and 96 mGy) emitted from 3 Cs-137 sources. XRF analysis confirmed the effectiveness of the preparation method used, and the NBT salt exhibited excellent solubility (R2 = 0.93). The films exhibited an increasing yellow hue as the concentration of NBT dye rose. Following irradiation, they took on a yellowish-brown tint, intensifying with higher gamma doses. PVA/NBT films, when stored in the dark, demonstrated good stability for 30 days post-irradiation. Analysis using ImageJ software unveiled that the relative density of the red color heightened proportionally with the concentration of NBT dye. XRD patterns showcased the clarity of structural rearrangements occurring after irradiation with high NBT concentrations. Two distinct peaks were registered at 2θ = 20.12 and 40.94 °, which shifted to 2θ = 19.74 and 41.30 ° post-gamma irradiation. The CIELab system study and K/S color strength indicated that increasing the NBT dye concentration led to a linear rise in color strength with escalating low gamma doses. Through a comprehensive assessment, it is concluded that PVA/NBT film can be effectively employed as a dosimeter for low gamma doses in diagnostic radiology. HIGHLIGHTS Nine different concentrations of NBT dye were used to prepare PVA/NBT films. The standard dose scale in diagnostic radiology (mGy) was applied in this work. CIELab system parameters showed a linear increase with increasing applied dose. XRD pattern recorded a shifted peak after irradiation from 2θ = 20.12 to 19.74 °. The dose-response was affected by increasing the NBT dye to a certain concentration. GRAPHICAL ABSTRACT

One-bath dyeing and antibacterial finishing of cotton fabric using reactive dye and silver chloride: a sustainable approach

One-bath dyeing and antibacterial finishing of cotton fabric using reactive dye as colorant and silver chloride (AgCl) as an antibacterial agent was conducted to streamline the process and enhance its economic efficiency. The effectiveness of the antibacterial agent in reactive dyeing of cotton fabric, was evaluated through exhaust method with 0.5% AgCl and continuous (pad dry cure) method with 5 g/l of AgCl, utilizing various dye concentrations (1%, 3%, 5% for exhaust; 1g/l, 3g/l, 5g/l for pad dry cure) according to a standard reactive dye recipe. Characterization of the one-bath dyed, and antibacterial finished cotton fabric was performed using K/S values to determine the optimal dye shade concentration and antibacterial activity was evaluated using agar diffusion method. It was observed that the exhaust method revealed an optimum dye concentration at (AgCl 0.5% and dye 5%), while pad dry cure method showedoptimal dye concentration at (AgCl 5g/l and dye 5g/l). Antibacterial tests were conducted on the optimal specimens from both methods (AgCl 0.5%, 0.2%, dye 0.5% for exhaust; dye 5g/l, AgCl 5g/l, 2g/l for pad dry cure), showcasing resistance against bacterial growth. While inhibition zones were observed on treated specimens of the exhaust method, whereas the treated specimens of the pad dry cure method exhibited complete resistance to bacterial growth around the specimen.

Spent Tea Leaves as an Adsorbent Material: Preparation, Characterization, and Application

The adsorption of Congo Red (CR) on the surface of Spent Tea Leaves (STL) was evaluated in an aqueous system. The study was carried out for the establishment of a standard wastewater treatment method that would remove reactive dyes by employing spent tea leaves as a bio-adsorbent. The effect of various parameters like amount of adsorbent, contact time, concentration of dye, and pH on the adsorption was studied. The adsorption capacity was monitored with a UV-visible spectrophotometer. The maximum adsorption of dye was observed at adsorbent mass of 3.5g /100 mL, at 8×10-5 M CR concentration, at pH = 9.72 and 50 minutes of contact time. The experimental results suggest that the adsorption of CR on the surface of STL is an exothermic process. The adsorption of CR on STL is found to follow pseudo first order kinetics. Based on the findings, it’s feasible to draw the conclusion that spent tea leaves would be a better adsorbent for the removal of reactive dyes from the wastewater.

Synthesis of Ternary Layered Double Hydroxides and Application for Wastewater Treatment

AbstractThis study systematically investigates the optimization of synthesis parameters for ternary layered double hydroxide (LDH) to achieve a pure phase and high crystallinity. The , LDH is synthesized using the coprecipitation method and applied for wastewater treatment. The ternary LDH is synthesized at 60 °C for 24 h and exhibited maximum crystallinity with a crystallite size of 4 nm. The crystallinity index (CI) is a quantitative indicator of crystallinity, which is calculated using the X‐ray diffraction (XRD) method. The influence of reaction time on the structural characteristics of this LDH was thoroughly investigated, mainly focusing on achieving well‐crystalline LDH. Experimental results revealed a direct correlation between reaction time and crystallinity. This study highlights the significant influence of controlled synthesis and reaction time on producing high crystalline ternary LDH. The role of different parameters, such as solution pH, adsorbent dosage, contact time, and dye concentration, has been investigated. The adsorption isotherm data is analyzed using different isotherm models, which shows this material having a significant adsorption capacity of 82.92 mg/g for Congo Red dye.

Sctudies on adsorption of Brilliant Green from aqueous solution onto nutraceutical industrial pepper seed spent

The study proposed the removal of Brilliant Green, a cationic dye, by adsorption process from wastewater solution utilizing a low-cost adsorbent such as Nutraceutical Industrial Pepper Seed Spent (NIPSS). The study comprises an investigation of the parametric influence on the adsorption process. The parameters identified are pH, dye concentration, process temperature, quantity of the adsorbent, and particle size. The study of statistics found from experiments was carried out by incorporating Freundlich, Brouers-Sotolongo, Langmuir, Toth, Sips, Jovanovic, and Redlich-Peterson isotherm models. The adsorption kinetics were determined by implementing pseudo-first-order and second-order models, diffusion film models, and Dumwald-Wagner and Weber-Morris models. The experimental adsorption capacity qe was found to be about 130 mg/g. This value was closest to the maximum adsorption of 144.6mg/g predicted by the Brouers-Sotolongo isotherm which had a correlation coefficient (R2) of 0.998. The adsorption kinetics data was confirmed to be a pseudo-second-order model. The change in free energy, enthalpy change, and entropy change were vital thermodynamic factors in concluding that adsorption is almost spontaneous and endothermic process. Change in enthalpy (ΔH°) reduced value indicates the physical nature of the process. The adsorption of BG dye on the adsorbent surface was authenticated by FTIR spectroscopy and SEM imaging. A Central Composite Design (CCD) Quadratic model under Response Surface Methodology (RSM) was implemented for statistical optimization of adsorption capacity for the five parameters studied, namely, time, temperature, concentration of the dye, weight of the adsorbent, and pH. Software Design Expert 7.0 was used to evaluate 3D contour plots. The process of optimization yielded a value of 350 mg/g. Thus, incrementing the adsorption process by 84.2 %. The study provides insights on various dye and adsorbent interaction possibilities and derives that NIPSS is an efficient adsorbent to extract BG dye from wastewater solutions.

Hydrothermal synthesis of Gd-doped CaO nanoparticles from lemon peel extract for efficient photocatalytic degradation of methylene blue under UV and sunlight

Water pollution, exacerbated by the improper disposal of non-biodegradable dyes from textile and paper industries, poses a significant global threat. Addressing this challenge, the present study focuses on the photocatalytic degradation of methylene blue (MB), a harmful azo dye, using novel Gd-doped CaO NPs synthesized with waste lemon peel extract (LPE) as a green stabilizing agent. The CaO NPs, calcined at 700 °C and subsequently doped with gadolinium (Gd) at concentrations of 2, 4, and 6 mmol via hydrothermal method, were characterized using various techniques. Fourier Transform Infrared Spectroscopy (FTIR) confirmed presence of Ca-O and Gd-O with the bond lengths of 1.7 Å and 1.2 Å, respectively. UV–Visible spectra revealed a bandgap in the range of 3.28 to 2.50 eV. X-ray Diffraction (XRD) patterns confirmed crystallinity with the crystallite size estimated using the Scherrer and William sons-Hall (W-H) methods ranging from 18 to 38 nm and XRD deduced specific surface area between 47 and 98 m2/g. Dynamic Light Scattering (DLS) showed particle size distribution from 38 to 130 nm, and zeta potential values ranging from −13.5 to −19.9 mV. The photocatalytic activity against MB was tested under UV light and natural sunlight at dye concentrations of 10, 15, and 20 ppm. The 4 mmol Gd-doped CaO NPs achieved a remarkable 98 % degradation efficiency within 2 h of sunlight exposure at a 10 ppm dye concentration. The degradation followed a pseudo-first-order reaction, and a possible degradation pathway was proposed for methylene blue. This study concludes that Gd-doped CaO NPs are highly effective, sustainable, and cost-efficient photocatalysts for wastewater treatment.