Freundlich Isotherm Research Articles

Two-dimensional MXene and molybdenum disulphide for the removal of hexavalent chromium from water: A comparative study

Chromium is a carcinogenic heavy metal that accumulates in plant and animal bodies. New materials for efficient removal of chromium from water bodies are in high demand. MXene was synthesized from MAX phase by using ammonium fluoride as an etching agent while molybdenum disulphide was synthesized by hydrothermal method. The pseudo-second order kinetic model described the adsorption of hexavalent chromium on MXene and molybdenum disulphide whereas the Freundlich Isotherm model best fitted for Mxene, and Langmuir Isotherm model was more suitable in case of molybdenum disulphide. The adsorption capacity obtained by MXene for hexavalent chromium was 59.8 mg/g (At Dosage = 1 g/L, T = 298 K, Time = 9 h, pH = 2, Co = 30 mg/L) and 113.7 mg/g in case of molybdenum disulphide (At Dosage = 0.5 g/L, T = 298 K, Time = 1.5 h, pH = 2, Co = 30 mg/L). Thermodynamic investigations showed that the process was endothermic and spontaneous. The coexisting ions showed a decrease in removal percentage up to 70 % and 79 % in case of MXene and molybdenum disulphide, respectively, after fifth cycle. It can be inferred that these developed materials have the advantages of simplicity for reducing heavy metal pollution.

Green synthesis of Carbonized Chitosan-Fe3O4-SiO2 nano-composite for adsorption of heavy metals from aqueous solutions

Water pollution with heavy metals owing to industrial and agricultural activities have become a critical dilemma to humans, plants as well as the marine environment. Therefore, it is of great importance that the carcinogenic heavy metals present in wastewater to be eliminated through designing treatment technologies that can remove multiple pollutants. A novel green magnetic nano-composite called (Carbonized Chitosan-Fe3O4-SiO2) was synthesized using Co-precipitation method to adsorb a mixture of heavy metal ions included; cobalt (Co2+), nickel (Ni2+) and copper (Cu2+) ions from aqueous solutions. The novelty of this study was the synthesis of a new nano-composite which was green with magnetic properties to be more sustainable and environmentally friendly. Its magnetic properties made it separated easily from solutions after accomplishment of the adsorption process using a magnet. Extended Freundlich isotherm was the best fitted model with maximum adsorption capacity of the metal ions mixture 2908.92 mg/g. Different experimental parameters have been studied included the initial concentration for a mixture of nickel, cobalt and copper metal ions (0.05–0.1 molar), dosage of adsorbent (0.5–3.5 g/L) and contact time (6–90 min) to investigate their changing effect on the removal percents of the heavy metal ions mixture from aqueous solutions. The experimental adsorption percent of cobalt ion ranged from 1.58 to 64.28%, nickel ion adsorption percent ranged from 10.68 to 94.12% and copper ion adsorption percent ranged from 4.41 to 76.23% at pH = 9 were based on the combination of the adsorption process parameters.

Phytochemical preparation of Zinc Stannate nanoparticles by using lemon and grapefruit peels for removal of cadmium ions

The synthesis of Zinc Stannate (Zn2SnO4) nanoparticles may be achieved by utilizing lemon and grapefruit peels, as indicated by the results of this study. This analysis outlines a sustainable, cost-effective, and readily available approach. The Zn2SnO4 nanoparticles were generated biologically and were discovered to have a cubic crystalline structure, as established by structural analysis using Rietveld refinement. TEM microstructural examinations revealed that Zn2SnO4 nanoparticles exhibit a homogeneous distribution and possess an average diameter of around 21 nm. The Zn2SnO4 nanoparticles have an optical energy band gap of 3.05 eV and demonstrate a UV region peak, which showed that Zn2SnO4 nanoparticles were being formed. More precisely, the pH of the solution greatly affects the absorption of Cd2+ ions. Kinetic analysis involves the use of two types of models: pseudo-first-order and pseudo-second-order. The previous model yields an R2 value of 0.9031 and a rate constant (k1) of 0.41 × 10−2 min−1. However, the pseudo-second-order model provides a better match, as seen by its very high R2 value of 0.9932 and rate constant (k2) value of 4.4 × 10−3 g.(mg.min)−1. In addition, isotherm modeling shows that the experimental data closely match the Freundlich isotherm model.

A green solution for eliminating methylene blue and crystal violet dyes using eco-friendly zinc oxide nanoparticles synthesized from Dracaena trifasciata

Modern technological development has unavoidably resulted in more pollution, especially in aquatic environments. While extensively utilized in various industries, cationic dyes pose a significant threat to both the environment and human health, ranking among the most hazardous pollutants. When exposed to these dyes, one may experience skin irritation and allergic dermatitis because they are frequently mutagenic, toxic, carcinogenic, and resistant to biodegradation. The continued release of these dyes into the environment exacerbates human health and ecosystem concerns. This work investigates the possibility of eco-friendly zinc oxide nanoparticles, which are produced by the co-precipitation method from leaf extracts of the Dracaena trifasciata plant, also referred to as snake plant, for the elimination of the cationic dyes methylene blue and crystal violet. This work presents a novel approach for synthesizing eco-friendly zinc oxide nanoparticles using leaf extract from Dracaena trifasciata. To examine the eco-friendly zinc oxide nanoparticles, characterization studies were carried out using various instrumental methods. The best conditions for removing methylene blue and crystal violet were found through batch adsorption investigations, which produced removal percentages of 86 % and 88 %, respectively, under specific conditions. The eco-friendly zinc oxide nanoparticles achieved maximum adsorption capacity and effective removal of methylene blue and crystal violet dyes under the following conditions: a pH value of 10, nanoparticle concentration of 0.06 g, reaction time of 50 min, dye concentration of 50 mg/L, and reaction temperature of 40 °C. Isotherm investigations demonstrated that the adsorption of methylene blue dye by eco-friendly zinc oxide nanoparticles followed the Temkin isotherm model, whereas the adsorption of crystal violet dye followed the Freundlich isotherm model. The kinetic parameters describing the adsorption of methylene blue and crystal violet dye onto eco-friendly zinc oxide nanoparticles were identified as pseudo-first-order and Elovich models, respectively. Following the above-mentioned studies, eco-friendly zinc oxide nanoparticles were subjected to additional characterization in order to assess their potential for wastewater treatment.

Efficient removal of polycyclic aromatic hydrocarbons from aqueous solutions using green cyclodextrin-maltodextrin nanosponge incorporated polyvinyl alcohol cryogel

Developing efficient adsorbents for removing polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions is a significant and worthwhile approach. In this study, we showcase a method for fabricating β-cyclodextrin-maltodextrin nanosponges (βCD-MD) incorporated polyvinyl alcohol (PVA) cryogel for removing PAHs from aqueous solutions. The composite nanosponges enhanced the adsorption efficiency of PAHs such as Naphthalene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, and Benzo[a]pyrene from water samples and the porous PVA cryogel helped to entrap and prevent the loss of the adsorbent. This efficacy was attributed to the strong affinities of PAHs toward βCD-MD nanosponges, facilitated by hydrophobic interactions between the analytes and the hydrophobic inner region present in both dextrins. The removal efficiency of the prepared βCD-MD/PVA composite cryogel was more than 95 % for all 8 PAHs (C0 = 5.0 mg/L) in less than 30 min, and the experimental data were well described by the Freundlich isotherm and the pseudo-second-order kinetic model. Additionally, the βCD-MD/PVA composite cryogel exhibited a maximum adsorption capacity ranging from 16.34 to 18.49 mg/g for eight PAHs. Moreover, the thermodynamic study revealed that the adsorption of PAHs was an endothermic and spontaneous process. The βCD-MD/PVA composite cryogel exhibited an abundance of polar functional groups along with numerous hydrophobic cavities and regions. It demonstrated high mechanical and thermal stability and maintained high removal efficiency even after seven adsorption–desorption cycles. Overall, it was concluded that βCD-MD/PVA composite cryogel can be utilized as a high-performance, eco-friendly, and sustainable alternative for PAH removal.

Nitrate removal from aqueous solution using fuller’s earth and modified fuller’s earth

ABSTRACT Water, a vital resource for ecosystems and human populations, is facing increasing nitrate contamination due to agricultural runoff, industrial discharge and improper waste disposal. The present study focuses on the efficacy of nitrate removal through adsorption using fuller’s earth (FE) and modified fuller’s earth (acid-treated) (MFE) as adsorbents. The impact of initial pH (2.0–7.0), contact time (5–240 min), adsorbent dosage (1–30 g/L), initial nitrate concentration (50–250 mg/L) and temperature (30–50°C) on nitrate removal using fuller’s earth were studied. The maximum nitrate removal was observed at pH 2.0, and equilibrium was reached in 120 min at 30℃. The Freundlich isotherm best fit the equilibrium data. The maximum nitrate uptake of fuller’s earth and modified fuller’s earth were 84.75 mg/g and 85.47 mg/g, respectively. Nitrate removal by FE and MFE followed a second-order kinetic equation. Thermodynamic studies showed spontaneity and the exothermic nature of the nitrate adsorption process. ∆H° values were −44.96 and −42.63 kJmol−1 for FE and MFE and ΔS° was −85.11 and −74.52 Jk−1mol−1 for FE and MFE, respectively. FE, known for its exceptional adsorption capacity owing to its porous structure and high ion-exchange capacity, has demonstrated a remarkable affinity for nitrate ions in batch studies.

Poly(allyl alcohol-co-vinyl acetate)-grafted concrete waste for adsorptive removal of As(III)

This study focused on the synthesis of concrete waste grafted with a polymer of allyl alcohol and vinyl acetate as a novel nano adsorbent and the investigation of its ability in the adsorptive removal of Arsenic (As(III)) from aqueous solutions. The prepared nano adsorbent was characterized using X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. Various parameters were optimized by response surface methodology and central composite design model to achieve the highest As(III) removal efficiency, including the solution's temperature, contact time, and pH. The model predicted a maximum removal efficiency of 92 % under the optimal conditions (temperature = 25 °C, contact time = 24 min, and pH = 7), resulting in a sorption capacity of 6.81 mg g−1. The zero point of charge for the nano adsorbent was obtained at about 6.5. The experimental data for As(III) sorption onto the nano adsorbent was well-fitted by the Freundlich isotherm and pseudo-1st-order kinetic models. This suggests that the adsorption process involves the formation of a multilayer of As(III) on the adsorbent surface, and it occurs through physical interactions rather than chemical reactions. The reusability of the nano adsorbent was evaluated, demonstrating a removal efficiency exceeding 72 % even after seven recycling cycles. The presence of interfering cations influenced the removal efficiency in the following order: Pb2+>Mn2+>Cu2+>Zn2+>Ni2+. The prepared nano adsorbent showed significant efficiency in removing As(III) from well water and river water samples, with a repeatability range of 1.09–2.51 %.

Characterization and Adsorption Capacity Evaluation of ZnCl2 Impregnated Cassava Peel Carbon for Removal of Fe, Ca, Mg and Zn ions in Wastewater from Cassava processing Industry

The objective of this paper was to prepare, characterize and evaluate the adsorption capacity of cassava peel carbon (CPC) impregnation with ZnCl2 salt for the removal of Fe, Ca, Mg and Zn ions in wastewater derived from cassava processing which has been noted to be problematic in terms of management. CPC and cassava peel activated carbon (CPAC) at 1:3, 2:3, and 1:1 impregnation levels were placed in fixed bed adsorption columns to determine metal ion adsorption capacities of the carbon materials after 120, 240, 360 and 480-minute contact times. Langmuir and Freundlich isotherm models were used in assessment of adsorption of the carbon materials, while pseudo-first and second order models were used to validate the adsorption kinetics of Fe, Ca, Mg and Zn. Pore space development was also monitored using scanning electron microscope (SEM) imagery. Results SEM images revealed hexagonal honeycomb surface structure at 2:3 impregnation level and spongy configuration at 1:1 ZnCl2 impregnation level. The correlation coefficient of Langmuir isotherm was observed to be between 0.86 to 1, indicating that the adsorbent is very good in adsorption of the metals, however, Freundlich isotherm is found to be unfavorable in describing CPAC’s capacity in adsorbing zinc ion contaminant. The pH of the carbon materials was observed to have increased while the bulk density reduced with increasing level of impregnation. Conclusively, CPC and CPAC materials are well suited to Langmuir isotherm as well as pseudo-second order model, implying that adsorption occurs well in a monolayer form on the surface material surface.

A Green Approach to Oil Spill Mitigation: New Hybrid Materials for Wastewater Treatment.

This study focuses on the development of adsorptive materials to retain degraded 5w40 motor oil. The materials were prepared using xanthan (XG) and XG esterified with acrylic acid (XGAC) as the polymeric matrix. LignoBoost lignin (LB), LB esterified with oleic (LBOL), stearic acid (LBST) and montmorillonite (CL) were added into XG and XGAC matrices to obtain the adsorbents. Adsorption experiments revealed that XG/CL/LBOL had the highest adsorption capacity at 46.80 g/g, followed by XGAC/CL at 45.73 g/g, and XG/CL at 37.58 g/g. The kinetic studies, employing the pseudo-second-order (PSO) model, indicated rapid sorption rates with a good correlation to experimental data. FTIR spectra analysis have evidenced the physical nature of adsorption process, involving interactions such as hydrogen bonding, van der Waals forces, and π-π interactions. Equilibrium data fitting to the Henry, Freundlich, and Temkin isotherm models showed that the adsorption occurs within materials diverse pore structures, enhancing oil retention. Structural parameters like density, porosity, and surface area were pivotal, with XG/CL/LBOL showing the most favorable properties for high oil adsorption. Additionally, it was found that the adsorption efficiency was influenced by the material's morphology and the presence of chemical modifications. This comprehensive evaluation highlights the potential of these novel adsorptive materials for environmental remediation applications, offering an efficient and sustainable approach to reducing degraded motor oil pollution.

Unveiling the potential of Fe2O3/TiO2 system to produce clean water: An effective and low‒cost approach for arsenic removal from ground water

The aim of this project is to estimate and eliminate arsenic by using cost‒effective approach. For the purpose, anatase TiO2 has been synthesized and sensitized with Fe2O3 using hydrothermal approach. As‒synthesized adsorbents namely Fe2O3/TiO2 were employed to remove the arsenic (III and V) contents in the form of arsenomolybdate complex (AMC). The structural morphologies and optical characteristics have been examined and assessed by various advance approaches like XRD, FTIR, Raman, SEM and AFM techniques. The BET, EDX and XPS techniques have confirmed the porosity, phase purity and chemical compositions. The stability of adsorbents was evaluated using thermo–gravimetric analysis. To extend the utility of adsorbents for successful implementation, various ground drinking water samples have been collected from Tehsil Jahania‒PK. For the quick removal and spectroscopic quantifications, arsenic contents were first converted to the arsenomolybdate complex (AMC) and then extracted via adsorption. Langmuir and Freundlich isotherm models were employed to evaluate and confirm the adsorption efficiencies, whereas Temkin model was employed to assure the electrostatic attraction between Fe2O3/TiO2 and AMC. Results indicate that the maximum adsorption capacity of Fe2O3/TiO2 is 130.1 mg/g. On the basis of survey reports and results, it has been concluded that this approach hold potential to replace the traditional adsorbents used for arsenic removal technologies.

Construction of nanocomposite hydrogel by TiO2-carbon quantum dots encapsulated in alginate with a highly efficient adsorption and photodegradation of dye pollutants

This presentation introduces an integrated photocatalyst/adsorbent system, achieved through immobilization and encapsulation of the TiO2 doped with CQDs (carbon quantum dots) nanocomposite within the calcium alginate (CaAlg) matrix. The nanoparticles and nanocomposites were analyzed using various techniques, including FE-SEM, EDX, TEM, XRD, PL, FT-IR, BET, and UV–vis DRS, to determine their structure and properties. The TiO2/CQDs/Alg nanocomposite hydrogel considerably influenced the adsorption and photocatalytic degradation of methylene blue (MB) as a dye pollutant. The adsorption studies were conducted to assess parameters such as adsorption capacity, kinetic behavior, and adsorption isotherms. The outcomes revealed a high adsorption capacity (44.13 mg/g at 90 min) and indicated that the pseudo-second-order kinetic model was highly suitable for describing the adsorption behavior of MB. Moreover, the Freundlich isotherm exhibited better fitting capabilities compared to the Langmuir isotherm. CQDs not only facilitated the transfer of photoelectrons from the TiO2 surface, preventing recombination of electron-hole pairs but also enhanced visible light absorption by the upconversion photoluminescence. The TiO2/CQDs/Alg displayed excellent photodegradation performance (97 %) of MB compared with TiO2 and TiO2/CQDs under visible light due to the abundance of active sites for MB adsorption and photocatalytic reactions. The TiO2/CQDs/Alg hydrogel exhibited excellent reusability in degrading MB for up to five consecutive cycles and showed significant swelling behavior across a broad pH range, reflecting the hydrogel's exceptional stability. The use of charge carrier scavengers indicated that O2˙−radicals were the primary surface species involved in the photodegradation of MB.

Synthesis of Activated Charcoal from Coconut Shell for the Removal of Crude Oil Spill

Crude oil spills have devastating effects on the environment, particularly aquatic ecosystems. The purpose of the present research is to determine whether dry coconut shells can be used as raw materials to make activated charcoal (AC) via pyrolysis and whether they can be utilized as natural sorbents to clean up crude oil spills. The UV-Vis spectrum of the synthesized CSAC shows distinct peaks at 230 and 260 nm, whereas the activated charcoal exhibits peaks at 231 and 261 nm. The FTIR spectra of the synthesized CSAC reveal a medium broad absorption peak at 3307.2 cm⁻¹, while the raw coconut shell's FTIR spectra show a medium sharp peak at 2945.3 cm⁻¹. The SEM images highlight the unique structural properties of CSAC, showcasing high porosity, varied pore sizes, rough surface topography, and the presence of micropores and mesopores. The chemical activation significantly increased the hydrophobicity of the adsorbent, creating CSAC with a much better adsorption capacity for crude oil removal, having a maximum adsorption capacity of 4840.0 mg/g and the highest percentage of crude oil removal at 99.9985%, as proven by batch experiments for different adsorbent dosages. The batch experimental results indicated that the percentage of crude oil removal increased with an increase in adsorbent dosage and contact time. Based on the correlation coefficients (R²) values (close to unity), it was generally observed that the plots match the Freundlich isotherm better than the Langmuir isotherm model. These findings have made the synthetic CSAC an attractive, useful, and environmentally friendly adsorbent.

Improving landfill liner performance with bentonite-slag blend permeated with ammonia for a Municipal solid waste landfill

Leachate emanating from landfills contains ammonia which may cause serious health effects on living things. An effectively designed clay barrier should not allow the contaminant to infiltrate the soil and groundwater systems. The utilization of certain industrial by-products in engineered landfill barriers, not only reduces the need for conventional liner materials but also helps in sustainable waste management. This study investigated the hydraulic conductivity, unconfined compressive strength, compaction, and adsorption characteristics of lithomargic clay blended with an optimum percentage of bentonite (10%) and granulated blast furnace slag (15%) permeated with ammonia. The results revealed that increasing the content of granulated blast furnace slag decreased the maximum dry density while increasing the optimum moisture content. In comparison to lithomargic clay, the hydraulic conductivity of the amended soil liner permeated with ammonia decreased from a value of 3 × 10−8 m/s to 5 × 10−10 m/s. The unconfined compressive strength of the amended soil specimens showed an increasing trend with curing times (i.e., 0, 14, 28, and 56 days). The batch adsorption results revealed that Freundlich and Langmuir's isotherm fits the equilibrium adsorption data and the adsorption of ammonia on clay liner follows non-linear behaviour. Overall, the experimental results implied that lithomargic clay blended with 10% bentonite and 15% granulated blast furnace slag can be used as an impermeable soil reactive barrier in engineered landfills.

Synthesis of eco-friendly polyaniline-zeolite nanocomposite for pollutant remediation: Empowered by robust machine learning algorithm

The present research assesses the synthesis of an eco-friendly polyaniline and zeolite 4A (4 Armstrong) nanocomposite for enhanced adsorption of dye and heavy metal. Zeolite has been synthesized utilizing natural Kutch-sourced Kaolin clay. The materials synthesized were characterized via various instrumental techniques which confirms the formation of the desired materials. The composite exhibits superior performance in removing hazardous pollutants, demonstrating the removal of 98.5 % chromium in 12 min and 99.8% Congo red in 50 min, individually. Furthermore, for simultaneous removal, the composite continued displaying remarkable performance having a removal rate of 99% and 98.5 % for Congo red and chromium, respectively within 50 min, only. The nanocomposite follows the Freundlich isotherm model for chromium removal indicating physisorption and the Langmuir isotherm model for Congo removal signifying chemisorption. Artificial intelligence and machine learning (ML) techniques have been employed on the data set for the simulation of the adsorption percentage of the synthesized adsorbent. Various uncharted data visualizing techniques, including scatter plots, correlation coefficients, and mutual information were applied to explain the correlation between experimental variables. Conventional regression techniques showed poor performance with a high mean squared error (MSE) of 23 and an R2 value of 0.89. However, Bayesian optimization assisted ML model significantly improved the results. The Gaussian process with a polynomial function was the best performer, achieving an R2 value of 0.99 and mean squared error of 0.008. This research highlights the novel synthesis and effectiveness of the adsorbent materials, demonstrating the potential of machine learning in environmental remediation.

Study on the preparation of Nano-Fe3O4 by steel pickling waste liquor and its effective removal of Cr (VI) from wastewater

In order to comprehensively treat and utilize steel pickling waste liquor (SPWL), this study used SPWL as raw material to prepare two different crystalline forms of Nano-Fe3O4 by co-precipitation and precipitation-oxidation methods, and investigated their removal effect on Cr(VI) in wastewater. The two kinds of Nano-Fe3O4 were characterized using SEM, XRD, and VSM, and the results showed that the Nano-Fe3O4 synthesized by the co-precipitation method has better properties. The two kinds of Nano-Fe3O4 were used to remove Cr(VI) in wastewater, the adsorption capacity could reach 38.38 mg/g and 15.83 mg/g, respectively. Five adsorption kinetic models and five isothermal adsorption models were used to study the adsorption mechanism of Fe3O4 on Cr(VI). The adsorption process of Cr(VI) by Nano-Fe3O4 was explained well using the pseudo-second-order and Freundlich isotherm model, and the results showed that the adsorption process mainly involved physical and chemical adsorption. Through the characterization analysis before and after the reaction, the removal mechanism of Cr(VI) by Nano-Fe3O4 prepared from SPWL is mainly attributed to electrostatic adsorption and reduction reaction. According to the market survey and analysis, the production cost is reduced by at least 58.33 % compared to that of Nano-Fe3O4 prepared using analytical purity in the market. Therefore, the preparation of Nano-Fe3O4 by steel pickling waste liquor provides an economical and effective way to remove heavy metal ions in wastewater.

Green and eco-friendly scalable synthesis of chitosan-carbon nanocomposite for efficient dye removal

The integration of activated carbon with chitosan (CS) for dye removal offers a multitude of benefits, making this hybrid material a promising and efficient solution for water purification. Activated carbon (C) was synthesized from fruit wastes and then mixed with CS for the preparation of chitosan‑carbon nanocomposite (CSCNC) using ball milling technique. XRD and ATR-FTIR techniques affirmed the preparation of CSCNC. Additionally, the findings obtained from TEM and SEM analyses signifying the deposition of activated carbon onto the surface of CS. The majority of particle size and polydispersity index (PdI) for CSCNC were found to be 162.8 nm and 0.483, respectively as displayed from DLS technique. The current research work was examined the adsorption and desorption behaviors of Methylene Blue (MB) using CSCNC. Adsorption experiments reveal a time-dependent process characterized by an initial rapid phase and gradual approach to equilibrium, with the pseudo-second-order kinetics model providing the best fit. The adsorption capacity exhibited a rising pattern as pH increased, reaching its peak value of 912.4 mg/g. Both Langmuir and Freundlich isotherm models explained the equilibrium relationship between MB and the nanocomposite, offering insights into maximum adsorption capacity and surface characteristics. Desorption studies explored the nanocomposite's regenerative potential under varying conditions. The findings contributed to the sustainable design of water treatment technologies, emphasizing the nanocomposite's efficiency, scalability, and regenerative capabilities.

Biosorption of reactive amoxicillin antibiotic on Pithophora macroalgae in aqueous solution: Equilibrium and kinetic studies

The removal of antibiotics is a significant environmental concern due to their complex structure. Therefore, scientists are working on novel and efficient techniques for removing antibiotic compounds from aqueous solutions. The current research aims to utilize green Pithophora macroalgae for extracting the antibiotic amoxicillin (AMX). An investigation into the kinetics and equilibrium mechanism of the biosorption of reactive AMX on macroalgae biomass in aqueous solutions has been conducted. The effects of operating factors such as initial AMX concentration, contact time, biosorbent dosage, agitation speed, and pH were investigated. FT-IR, SEM, and point of zero charge pH (PZC) techniques were used to characterize the biosorbent. The Langmuir and Freundlich isotherms were examined to determine which model better fits the experimental data. The experimental data best matches the Langmuir isotherm model for AMX biosorption, with a maximum sorption capacity of 25.83 mg g-1. The kinetic model for the experimental results follows the pseudo-second order (R2 = 0.9992). According to this study, the biomass of the macroalgae Pithophora has been shown to be a promising biosorbent for the biosorption of AMX antibiotics, making it suitable for practical water and wastewater treatment applications.

Response surface modelling and optimization for copper removal from acid mine drainage using oxidized Himalayan pine needle biochar

ABSTRACT This study aims to investigate and compare the adsorption behaviour of pine needle biochar (PNB) and H2O2-oxidized PNB (OPNB) in eliminating Cu(II) from acid mine drainage. The PNB and OPNB adsorbents undergo comprehensive characterization through various techniques (BET, FTIR, SEM, and pHPZC). A central composite design was employed for designing experiments and optimizing the impact of process factors (metal concentration, adsorbent doses, contact time, and pH) on adsorption capacity. Pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetics models as well as Langmuir, Freundlich, and Temkin isotherm models were used to analyze the experimental data. Langmuir isotherm best fit (R2 > 0.99) the experimental data and adsorption capacities of 29.49 and 102.04 mg/g, were determined for PNB and OPNB, respectively. Under optimized experimental conditions, desorption studies revealed the reusability of OPNB about 80% even after four cycles. Fixed-bed column experiments were conducted at ambient temperature with an initial Cu(II) concentration of 125 mg/L and 5.0 g of adsorbent, utilizing a flow rate of 1 mL/min for both PNB and OPNB. These results indicate that oxidized biochar, synthesized for Cu(II) remediation, not only addresses Himalayan pine needle concerns sustainably but also exhibits potential applicability for removing other metal ions from aqueous environments.

Fabrication of novel vildagliptin loaded ZnO nanoparticles for anti diabetic activity

Diabetes mellitus (DM) is a rapidly prevailing disease throughout the world that poses boundless risk factors linked to several health problems. Vildagliptin is the standard dipeptidyl peptidase-4 (DPP-4) inhibitor type of medication that is used for the treatment of diabetes anti-hyperglycemic agent (anti-diabetic drug). The current study aimed to synthesize vildagliptin-loaded ZnO NPs for enhanced efficacy in terms of increased retention time minimizing side effects and increased hypoglycemic effects. Herein, Zinc Oxide (ZnO) nanoparticles (NPs) were constructed by precipitation method then the drug vildagliptin was loaded and drug loading efficiency was estimated by the HPLC method. X-ray diffraction analysis (XRD), UV–vis spectroscopy, FT-IR, scanning electron microscope (SEM), and EDX analysis were performed for the characterization of synthesized vildagliptin-loaded ZnO NPs. The UV–visible spectrum shows a distinct peak at 363 nm which confirms the creation of ZnO NPs and SEM showed mono-dispersed sphere-shaped NPs. EDX analysis shows the presence of desired elements along with the elemental composition. The physio-sorption studies, which used adsorption isotherms to assess adsorption capabilities, found that the Freundlich isotherm model explains the data very well and fits best. The maximum adsorption efficiency of 58.83% was obtained. Further, In vitro, anti-diabetic activity was evaluated by determining the α-amylase and DPP IV inhibition activity of the product formed. The formulation gave maximum inhibition of 82.06% and 94.73% of α-amylase and DPP IV respectively. While at 1000 µg/ml concentration with IC50 values of 24.11 μg/per ml and 42.94 μg/ml. The inhibition of α-amylase can be ascribed to the interactive effect of ZnO NPs and vildagliptin.

Probiotic bacterial adsorption coupled with CRISPR/Cas12a system for mercury (II) ions detection

The complex sample matrix poses significant challenges in accurately detecting heavy metals. In view of its superior performance for the biological adsorption of heavy metals, probiotic bacteria can be explored for functional unit to eliminate matrix interference. Herein, Lactobacillus rhamnosus (LGG) demonstrates a remarkable tolerance and can adsorb up to 300 μM of Hg2+, following the Freundlich isotherm model with the correlation coefficient (R2) value of 0.9881. Subsequently, by integrating the CRISPR/Cas12a system, a sensitive and specific fluorescent biosensor, “Cas12a-MB,” has been developed for Hg2+ detection. Specifically, Hg2+ adsorbed onto LGG can specifically bind to the nucleic acid probe, thereby inhibiting the binding of the probe to LGG and the subsequent activation of the CRISPR/Cas12a system. Under optimal experimental conditions, with the detection time of 90 min and the detection limit of 0.44 nM, the “Cas12a-MB” biosensor offers a novel, eco-friendly approach for Hg2+ detection, showcasing the innovative application of probiotics in biosensor.