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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]

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]

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]

Wastewater contamination with heavy metal(loids)s has become a worldwide environmental and public health problem due to their toxic and non-degradable nature. Different methods and technologies have been applied for water/wastewater treatment to mitigate heavy metal(loid)-induced toxicity threat to humans. Among various treatment methods, adsorption is considered the most attractive method because of its high ability and efficiency to remove contaminants from wastewater. Agricultural waste-based adsorbents have gained great attention because of high efficiency to heavy metal(loids)s removal from contaminated water. Chemically modified biosorbents can significantly enhance the stability and adsorption ability of the sorbents. The two mathematical models of sorption, Freundlich and Langmuir isotherm models, have mostly been studied. In kinetic modeling, pseudo-second-order model proved better in most of the studies compared to pseudo-first-order model. The ion exchange and electrostatic attraction are the main mechanisms for adsorption of heavy metal(loid)s on biosorbents. The regeneration has allowed various biosorbents to be recycled and reused up to 4-5 time. Most effective eluents used for regeneration are dilute acids. For practical perspective, biosorbent removal efficiency has been elucidated using various types of wastewater and economic analysis studies. Economic analysis of adsorption process using agricultural waste-based biosorbents proved this approach cheaper compared to traditional commercial adsorbents, such as chemically activated carbon. The review also highlights key research gaps to advance the scope and application of waste peels for the remediation of heavy metal(loid)s-contaminated wastewater. This review provides new information and insights on the potential utilization of agriculture-based biosorbents for the removal of contaminants, especially heavy metal(loid)s from toxic water/wastewater, as well as their mechanisms, adsorption efficiency, and regeneration ability. For practical perspective, biosorbent adsorption efficiency was elucidated by using various types of wastewater and economic analysis studies. [ABSTRACT FROM AUTHOR]

Soybean (Glycine max) is a protein-rich oilseed crop that is extensively used for cooking oil and poultry feed and faces significant challenges due to adverse global climatic conditions aggravated by the ongoing climate crisis. In response to this critical issue, this study was initiated to assess suitable zones for soybean cultivation, aiming to facilitate informed land use decisions within the semi-arid terrestrial ecosystem. Through the utilization of geostatistical interpolation, data layers encompassing soil, irrigation water, land use and land cover, topographic features, and climate information were generated and overlaid based on criterion weightage derived from the Analytic Hierarchy Process. The accuracy of land use and land cover was rigorously evaluated, yielding a 70% overall accuracy and a Kappa (K) value of 0.61, signifying an acceptable level of precision. Validation through the Receiver Operating Characteristic curve for soybean crop suitability demonstrated a highly satisfactory area under the curve of 0.738. The study estimates that out of 172,618.66 hectares, approximately 47.46% of the land is highly suitable (S1) for soybean production, followed by 21.36% moderately suitable (S2), 11.91% marginally suitable (S3), 7.00% currently not suitable (N1), and 12.28% permanently not suitable (N2). Conclusively, the findings suggest that the study area exhibits conducive climatic conditions, optimal soil health, and access to quality irrigation water, all of which have the potential to support soybean crops with improved agronomic practices. This investigation offers valuable insights to both farmers and policymakers concerning irrigation water quality, agricultural productivity, and soil degradation. [ABSTRACT FROM AUTHOR]

Trace elements (TEs) contamination of agricultural soils requires suitable criteria for regulating their toxicity limits in soil and food crops, which depends on their potential ecological risk spanning regional to global scales. However, no comprehensive study is available that links TE concentrations in paddy soil with ecological and human health risks in less developed regions like Pakistan. Here we evaluated the data set to establish standard guidelines for defining the hazard levels of various potentially toxic TEs (such as As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se, Zn) in agricultural paddy soils of Punjab, Pakistan. In total, 100 topsoils (at 0–15 cm depth) and 204 rice plant (shoot and grain) samples were collected from five ecological zones of Punjab (Gujranwala, Hafizabad, Vehari, Mailsi, and Burewala), representing the major rice growing regions in Pakistan. The degree of contamination (C d) and potential ecological risk index (PERI) established from ecological risk models were substantially higher in 100% and 97% of samples, respectively. The positive matrix factorization (PMF) model revealed that the elevated TEs concentration, notably Cd, As, Cr, Ni, and Pb, in the agricultural paddy soil was attributed to the anthropogenic activities and groundwater irrigation. Moreover, the concentration of these TEs in rice grains was higher than the FAO/WHO's safe limits. This study provided a baseline, albeit critical knowledge, on the impact of TE-allied ecological and human health risks in the paddy soil-rice system in Pakistan; and it opens new avenues for setting TEs guidelines in agro-ecological zones globally, especially in underdeveloped regions. [Display omitted] • This study unveiled trace elements (TEs) contamination in agricultural soils and rice. • TEs (e.g., As, Cd, Pb, Ni, Fe) concentrations exceeded their safe limits in soil. • Soil risk model revealed that 97% of samples posed high ecological risk. • Rice grain TEs contents were greater than their threshold values in 46% of samples. • These findings open new directions to set guidelines for TEs risk in agro-ecosystems. [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]

Abstract \nIn 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.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]

The current study delineated the distribution, (hydro)geochemical behavior and health risk of arsenic (As) in shallow (depth < 35 m; handpumps and electric pumps) and deep (depth > 35 m; tube wells) aquifers in five areas along the Indus River (Bhakar, Kallur Kot), Jhelum River (Jhelum) and Chenab River (Hafizabad, Gujranwala) floodplains of Punjab, Pakistan. Relatively, greater As concentration was observed in deep wells (mean: 24.3 µg L−1) compared to shallow wells (19.4 µg L−1), with groundwater As spanning 0.1–121.7 µg L−1 (n = 133) in three floodplains. Groundwater from Hafizabad (Chenab River floodplain) possessed the highest As (121.7 µg L−1), Na+ (180 mg L−1), Ca2+ (95 mg L−1), Cl− (101 mg L−1) and SO 4 2− (1353 mg L−1) concentrations. Arsenic health risk modeling indicated the potential carcinogenic (value > 10−4) and non-carcinogenic (hazard quotient > 1.0) risks for groundwater of all areas, with the utmost risk estimated for Chenab floodplain and deep aquifers. Positive saturation index values for Fe oxide mineral phases may suggest their potential role in As mobilization/release in these aquifer environments. This study provides critically-important and baseline knowledge for a widespread groundwater As examination along these three floodplains, which is vital for launching suitable As mitigation and remediation programs to reduce the potential health risk. ga1 • 61% of the groundwater wells exceeded arsenic (As) above WHO limit. • Elevated As (121 μg L−1) was found in Chenab River floodplain. • High As health risk was observed in deep wells (> 35 m) than in shallow wells (< 35 m). • Alkaline pH, salinity, with high Na, Ca, SO 4 contents control hydrogeochemistry. • Positive saturation indices for Fe oxides indicate potential role in As geochemistry. [ABSTRACT FROM AUTHOR]

Water contamination is a serious issue that has an impact on the whole globe. In the current work, adsorption technique was used to remove synthetic Reactive Blue MEBF 222 textile dye utilizing Cd-doped Co (Co 1 - x Cd 1.5x FeO 3 ), Zn-doped Co (Co 1 - x Zn 1.5x FeO 3 ), Cr-doped Co (Co 1 - x Cr 1.5x FeO 3 ), Zn-doped Ni (Ni 1 - x Zn 1.5x FeO 3 ), and Cr-doped Ni (Ni 1 - x Cr 1.5x FeO 3 ) perovskites, synthesized by sol-gel auto-combustion approach. According to the findings of batch adsorption studies, maximum adsorption was observed at pH 3 (45.62 mg/g), 0.01 g/50 ml dosage (36.67 mg/g), 60 min (14.31 mg/g), 100 ppm dye concentration (47.41 mg/g), and 308 K (35.96 mg/g) for Co 1 - x Cd 1.5x FeO 3 ; at 3 pH (42.94 mg/g), 0.01 g/50 ml dosage (35.33 mg/g), 60 min (12.88 mg/g), 100 ppm dye concentration (40.52 mg/g), and 308 K (31.31 mg/g) for Co 1 - x Zn 1.5x FeO 3 ; at 2 pH (38.82 mg/g), 0.01 g/50 ml dosage (32.20 mg/g), 60 min (11.98 mg/g), 100 ppm dye concentration (33.54 mg/g), and 308 K (29.34 mg/g) for Co 1 - x Cr 1.5x FeO 3 ; at 2 pH (34.97 mg/g), 0.01 g/50 ml dosage (30.41 mg/g), 60 min (10.46 mg/g), 100 ppm dye concentration (27.19 mg/g), and 308 K (26.12 mg/g) for Ni 1 - x Zn 1.5x FeO 3 ; and at 2 pH (31.22 mg/g), 0.01 g/50 ml dosage (25.04 mg/g), 60 min (9.48 mg/g), 100 ppm dye concentration (21.73 mg/g), and 308 K (23.61 mg/g) for Ni 1 - x Cr 1.5x FeO 3 . The pseudo-second-order model showed good fitness for adsorption kinetic data. Electrolytes, detergents/surfactants, and heavy metal ions had a substantial impact on the adsorption potential. The column adsorption experiments demonstrated optimal bed height, flow rate, and intake dye concentration to be 3 cm, 1.8 ml/min, and 70 mg/l, respectively, in the column experiment. With an adsorption capacity of 44.1 mg/g, reactive blue (RB) 222 dye was able to achieve its maximum adsorption. Detailed desorption of RB 222 dye was also achieved. The novelty of this adsorption method lies in its eco-friendliness, ease of handling, and cost-effectiveness., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)