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Industrial dye production chemicals contribute significantly to environmental pollution. This study explores the use of nanotechnology, specifically nano fertilizers and adsorption technology, for efficient removal of synthetic anionic dyes and enhancing agricultural production. Nano adsorbents (MnO, FeO, ZnO, and CuO) were generated using the co-precipitation method. Optimal conditions for Manganese oxide (MnO) were pH 2 (33.2 mg/g), dosage 0.01 g/50 mL, and adsorption capacity 77.2 mg/g. FeO optimal conditions were pH 2 (21.5 mg/g), dosage 0.01 g/50 mL, and qe 40.5 mg/g. CuO optimal conditions were pH 2 (28.2 mg/g), dosage 0.01 g/50 mL, and qe 71.3 mg/g. ZnO optimal conditions were pH 2 (25.4 mg/g), dosage 0.01 g/50 mL, and qe 64.2 mg/g. Pseudo 1st order and Freundlich sorption isotherms were best-fit models. Endothermic reactions were observed, indicating the sorption process's nature and feasibility. Electrolyte concentrations affected the sorption potential. Surfactants/detergents reduced sorption efficiency. 0.5 N NaOH proved most effective for desorption. In column studies, optimal conditions for acidic RB-71 dye sorption were 3 cm bed height, 1.8 mL/min flow rate, and 70 mg/L inlet dye concentration. Metal oxide showed exhibited crystal and polymorphs structure. FT-IR spectra depicted metal-oxide peaks between 400 and 899 cm−1. SEM micrograph reveals a spherical shape with an approximate size of 10–50 μm. The adsorption method's novelty lies in its easy handling, eco-friendliness, and cost-effectiveness, making it a promising technology for practical-scale application in addressing dye pollution. Highlights: Functionalization of the nano-adsorbent with other materials increases their surface area and subsequently, their uptake capacity. ZnO, CuO, MnO and FeO nanoparticles were synthesized using chemical co precipitation method. Efficient removal of anionic dye RB-71 dye. Adsorption process was well fitted to Freundlich isotherm, Pseudo-1st order kinetics and Intraparticle diffusion models. Desorption and reusability studies indicated excellent results and stability. [ABSTRACT FROM AUTHOR]

The sorbents Ni-Cu-FNP's, Ni-Zn-FNP's, Mn-FNP's, and Zn-FNP's were synthesised and utilised for the removal of Direct Golden Yellow RL dye. The optimum pH for the adsorption of direct golden yellow RL dye was 4, and 3 having the sorption capacities of 32.56, 30.44, 34.39, and 36.91 mgg−1 for Ni-Cu-FNP's, Ni-Zn-FNP's at 45 min and Mn-FNP's, Zn-FNP's at 60 min respectively with the optimum dosage of 0.05 g/50 mL. The maximum sorption capacities were 39.08 (Ni-Cu-FNP's), 35.08 (Ni-Zn-FNP's), 42.93 (Mn-FNP's), and 44.22 mg/g (Zn-FNP's) at 40°C, 37°C, 44°C, and 44°C respectively and the reduction observed in the sorption capacity by raising the temperature, showed that the process is exothermic The optimal initial concentration of dyes for all the sorbents having the maximum sorption capacities of 54.30 mg/g (Ni-Cu-FNP's), 51.25 mg/g (Ni-Zn-FNP's), 63.45 mg/g (Mn-FNP's), and 66.35 mg/g (Zn-FNP's) were 75, 100, 100, and 75 mg/L respectively to get maximal acidic dyes adsorption. Langmuir equilibrium isotherm for sorption showed good fitness on the data obtained by sorption while the pseudo-2nd-order proved good fitness on kinetic data of experiments. Surfactants, detergents, and different molar solutions of electrolytes (NaCl and AlCl3) decreased the sorption capabilities of the sorbents for the selected dye. [ABSTRACT FROM AUTHOR]

In this study, metal-doped quaternary nano ferrites (Co0.5Zn0.25M0.25Fe2O4, M = Ba, Cu, Mn, Ni and Sr) were synthesized and evaluated for their efficiency in removing Direct Orange-108 Acid Dye from aqueous solutions. The adsorption performance of these materials was systematically investigated under various conditions. Optimal pH levels for dye removal were found to be pH 2 (41.45 mg/g), pH 2 (36.37 mg/g mg/g), pH 4 (31.13 mg/g), pH 4 (44.75 mg/g), and pH and 3 (39.62 mg/g) at optimal dosage of 0.05 g/50 mL and at an initial concentration of at 75 ppm and 50 ppm for Co0.5Zn0.25Ba0.25Fe2O4, Co0.5Zn0.25Cu0.25Fe2O4, Co0.5Zn0.25Mn0.25Fe2O4, Co0.5Zn0.25Ni0.25Fe2O4 and Co0.5Zn0.25Sr0.25Fe2O4 respectively. Additionally, the study revealed that an optimum temperature of 40 °C enhanced the adsorption efficiency, resulting in adsorption capacities of 41.92 mg/g, 40.56 mg/g, 33.22 mg/g, 48.00 mg/g, and 43.71 mg/g for Co0.5Zn0.25Ba0.25Fe2O4, Co0.5Zn0.25Cu0.25Fe2O4, Co0.5Zn0.25Mn0.25Fe2O4, Co0.5Zn0.25Ni0.25Fe2O4 and Co0.5Zn0.25Sr0.25Fe2O4 respectively. The shaking time with optimal results were obtained at 45 and 60 min. Similarly, as a photocatalyst have optimal pH at 2, 3 and 4, optimum dose 0.05 g/50 mL, initial concentration of dye was 50 and 75 ppm with contact time of 45 and 60 minutes at 40 °C as optimum temperature. The pseudo second order adsorption kinetic model and Langmuir adsorption equilibrium isotherm displayed strong fitting for experimental data. While degradation kinetic follow BMG and second kinetic model. NH4OH solution showed maximum desorption The thermodynamic study demonstrated the exothermic character. The adsorption study of real textile effluents was also conducted that yielded valuable information. Highlights: Novel metal doped quaternary nano ferrites Co0.5Zn0.25M0.25Fe2O4 (M = Ba, Cu, Mn, Ni and Sr) were synthesized, characterized, and used for dye adsorption. Langmuir adsorption isotherm and pseudo second order kinetic model fitted best and proved most appropriate for this study. The size, changeable properties and shape are the most notable characteristics of nano ferrites, therefore the use of ferrites in many applications is enhancing day by day. [ABSTRACT FROM AUTHOR]

Adsorption is a highly effective method for wastewater quality adjustment, offering advantages such as low cost and availability of adsorbents. This study investigates the efficient removal of Anionic Actas Pink dye (AAPD), a major contributor to environmental pollution. Green adsorbents including lead oxide (PbO), zinc oxide (ZnO), cadmium oxide (CdO), and copper oxide (CuO) were synthesized via eco-friendly routes for AAPD removal. Maximum adsorption capacities (qe) were observed at pH 7 (PbO, ZnO, CdO) and pH 2 (CuO and native) with values of 83.83 mg/g at 100 ppm, 75.65 mg/g at 100 ppm, 70.50 mg/g 75 ppm, 61.21 mg/g at 150 ppm, and 52.69 mg/g at 150 ppm, respectively, using an adsorbent dose of 0.05 g/50 mL at temperature of 37°C, and 90 min contact time. Adsorption followed Langmuir isotherm for all adsorbents except native, with PbO also fitting Freundlich and Dubinin–Radushkevich isotherms. Kinetics adsorption data supported pseudo-second-order, while thermodynamic analysis indicated spontaneous and exothermic nature. Effects of electrolytes, surfactants, and desorption were also evaluated. Characterization through FTIR, SEM, and XRD confirmed the morphology and functional groups of these nano-quantum dots. Citrus limon peel-based biosynthesis offers sustainable, eco-friendly, and cost-effective alternatives, highlighting their potential for dye adsorption. Highlights: Explore cost-effective and efficient adsorption methods for wastewater treatment Discover effective adsorbents capable of efficiently removing Anionic Actas Pink Sustainable synthesis of green quantum dot was made using agricultural waste Gain insights into adsorption mechanisms through robust modeling techniques [ABSTRACT FROM AUTHOR]

Industries generate hazardous dye wastewater, posing significant threats to public health and the environment. Removing dyes before discharge is crucial. The ongoing study primarily focused on synthesizing, applying, and understanding the mechanism of green nano-biochar composites. These composites, including zinc oxide/biochar, copper oxide/biochar, magnesium oxide/biochar, and manganese oxide/biochar, are designed to effectively remove Actas Pink-2B (Direct Red-31) in conjunction with constructed wetlands. Constructed wetland maintained pH 6.0–7.9. At the 10th week, the copper oxide/biochar treatment demonstrated the highest removal efficiency of total suspended solids (72%), dissolved oxygen (7.2 mg/L), and total dissolved solids (79.90%), followed by other biochar composites. The maximum removal efficiency for chemical oxygen demand (COD) and color was observed at a retention time of 60 days. The electrical conductivity also followed the same order, with a decrease observed up to the 8th week before becoming constant. A comprehensive statistical analysis was conducted, encompassing various techniques including variance analysis, regression analysis, correlation analysis, and principal component analysis. The rate of color and COD removal followed a second-order and first-order kinetics, respectively. A significant negative relationship was observed between dissolved oxygen and COD. The study indicates that employing biochar composites in constructed wetlands improves textile dye removal efficiency. The novelty of this study is the selection of Cymbopogon as a proper plant for phytoremediation of dye along with green metal oxide coated biochar. These were selected due to their good ability to remove organic pollutant. This study demonstrates the uptake and degradation processes of persistent dye in constructed wetland. [ABSTRACT FROM AUTHOR]

This study explores the efficient removal of the synthetic anionic dye-reactive red Me4BL (RRMe4BL) from an aqueous medium which is a significant contributor to environmental pollution. The present study investigates the synthesis of zinc oxide, nickel oxide, cobalt oxide and copper oxide nano adsorbents (ZnO (II), NiO (II), CoO (II), CuO (II)) through the co-precipitation method and their effectiveness in eliminating the reactive red dye Me4BL(RRMe4BL). Maximum adsorption capacities were achieved at pH 2 for ZnO (96.1 mg/g), NiO (86.9 mg/g), CoO (93.4 mg/g) and at pH 6 for CuO (76.3 mg/g) under a 0.05 g/50 mL nano-adsorbent dose, 50 mg/L dye initial concentration and 25°C T and 90 min of contact time. The fitness of the pseudo-2nd-order model explained the kinetics, while Langmuir and Temkin adsorption isotherm highlighted the efficiency of the dye adsorption. Thermodynamic studies revealed the spontaneous and exothermic nature of adsorption. The influence of electrolytes, surfactants and desorption was also analysed. Characterisation of the nanoparticles was done through SEM, XRD and FTIR which revealed the morphology and functional groups of nano-adsorbents. The adsorption method used for eliminating this anionic red dye shows several benefits, including affordability, simplicity of use and the presence of intelligent adsorbents for environment-friendly removal of industrial dyes from wastewater. [ABSTRACT FROM AUTHOR]

The remediation of polluted soil and water stands as a paramount task in safeguarding environmental sustainability and ensuring a dependable water source. Biochar, celebrated for its capacity to enhance soil quality, stimulate plant growth, and adsorb a wide spectrum of contaminants, including organic and inorganic pollutants, within constructed wetlands, emerges as a promising solution. This review article is dedicated to examining the effects of biochar amendments on the efficiency of wastewater purification within constructed wetlands. This comprehensive review entails an extensive investigation of biochar's feedstock selection, production processes, characterization methods, and its application within constructed wetlands. It also encompasses an exploration of the design criteria necessary for the integration of biochar into constructed wetland systems. Moreover, a comprehensive analysis of recent research findings pertains to the role of biochar-based wetlands in the removal of both organic and inorganic pollutants. The principal objectives of this review are to provide novel and thorough perspectives on the conceptualization and implementation of biochar-based constructed wetlands for the treatment of organic and inorganic pollutants. Additionally, it seeks to identify potential directions for future research and application while addressing prevailing gaps in knowledge and limitations. Furthermore, the study delves into the potential limitations and risks associated with employing biochar in environmental remediation. Nevertheless, it is crucial to highlight that there is a significant paucity of data regarding the influence of biochar on the efficiency of wastewater treatment in constructed wetlands, with particular regard to its impact on the removal of both organic and inorganic pollutants. [ABSTRACT FROM AUTHOR]

Hybrid Layered Double Hydroxides (HLDH) are promising adsorption materials for water treatment due to their excellent anion exchange capacities, abundance of active sites, and eco-friendliness. HLDH was synthesized utilizing the co-precipitation technique in this work to demonstrate its applicability for the removal of direct sky-blue dye via an adsorption procedure. The effects of pH, dose, contact time, initial dye concentration, and temperature on the direct sky-blue dye adsorption efficiency were thoroughly investigated. The adsorbents were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), energy dispersive X-ray (EDX), and Brunauer–Emmett–Teller (BET). Under the best conditions, the maximum adsorption capacity has been achieved for Mg–Cr–Cl (42.95 mg/g) > Zn–Al–CO3 (39.76 mg/g) > Mg–Fe–Cl (38.08 mg/g). The adsorption of dyes on Mg–Cr–Cl, Zn–Al–CO3, and Mg–Fe–Cl followed a pseudo-second-order kinetic model and exhibited Langmuir-type monolayer adsorption. The influence of temperature was studied to determine the thermodynamic parameters. The estimated results showed spontaneous and exothermic adsorption processes. Electrolyte enhances the adsorption capacity to some extent, while surfactants block the sites, thus reducing the adsorption capacity. The maximum desorption of dye was influenced by the sodium hydroxide solution. The research described here might be utilized to create novel adsorbents with improved adsorption capacities for preserving the aquatic environment. [ABSTRACT FROM AUTHOR]

In this study, ZnFe2O4-Polyaniline (PANI), ZnFe2O4-Polystyrene (PST), and ZnFe2O4-Polypyrrole (Ppy) nanocomposites were synthesized by the adsorption method and characterized by field emission scanning electron microscopy and Fourier transform infrared spectrometer. Batch adsorption experiments were conducted for removing two types of hazardous dyes Red X-GRL and Direct Sky Blue 51 from an aqueous solution and the effect of pH, adsorbent dosage, contact time, and initial concentration of dyes were investigated. Meanwhile, kinetic, isotherm, and thermodynamic parameters were also determined. The electrolyte and surfactant effect was also tested for the prepared nanocomposites. To test the reusability desorption study was also conducted. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSRemoval of dyes has been a matter of great interest for researchers because of health and toxicity issues. In this research work, green biochar was produced using precipitation technique, and by the adsorption process, it was supported on layered double hydroxide (LDH). Biochar/LDH composites were synthesized from Neem, Amaltas, and Keekar stems, eggshells, and Eucalyptus (N, A, K, Egg, and Eu’s biochar/LDH-composite). These composites were employed to remove synthetic dyes from an aqueous solution. Recent studies have identified optimal conditions for LDH-composites under various parameters: pH 9 or 10 with a dosage of 0.05 g/50 mL yields higher adsorption capacities across different LDH composites, ranging from 40.74 to 48.30 mg/g at a reaction time of 90 min using a Pink-XFG dye concentration of 10 ppm, which is favorable. Temperatures of 303–308 K are suitable. Second-order kinetics, along with the Langmuir and Freundlich adsorption isotherms, along with exothermic reactions, presented good-fit results on adsorption kinetics and equilibrium data. The adsorption potential was significantly affected by various concentrations of electrolytes, surfactants, detergents, and heavy metal ions. 0.5 N hydrochloric acid was determined to be the most efficient agent for the process of desorption. These methods are very cost-effective, eco-friendly, and easy to manufacture.Utilizes eco-friendly biochar from natural sources for creating LDH nanocomposites.Establishes precise conditions (pH, temperature, etc.) for maximal dye removal.Demonstrates high capacity for toxic Pink-XFG dye removal from water.Assesses how electrolytes, heavy metals, and detergents affect adsorption efficiency.0.5 N hydrochloric acid is effective for desorption, enabling adsorbent reuse. [ABSTRACT FROM AUTHOR]