Adsorption Process Research Articles

Zigzag boron nitride nanotube functionalization as a sensor for the recognition of group IIA (Mg2+, Ca2+) metal ions, quasi-metal (Si2+, Ge2+) ions, and transition metal (Cu2+, Zn2+) ions: a computational study.

Boron nitride nanotubes (BNNTs) provide an exceptional and sophisticated platform for detecting metal ions with high surface area and remarkable chemical stability. Metal cations tend to bind to the surface of BNNTs, which leads to significant changes in the electrical properties of nanotubes. BNNT-based metal ion sensors have shown promising results in various applications, including water quality monitoring, biomedical research, industrial quality control, and environmental monitoring. In the present study, we have explored the electronic sensitivity of the BNNT to metal ions (Si2+, Ge2+, Cu2+, Zn2+, Mg2+, and Ca2+). The interaction between the ions with the pristine BNNT is performed in the solution phase. The results show that ion adsorption on the nanotube surface is exothermic and favorable. The density of states calculation is presented to investigate the electronic properties of the nanotube during the adsorption process. The results display that an increase in the electrical conductivity of the complexes accompanies the reduction in the energy gap. Based on the obtained data, the Si2+ and Ge2+ cations adsorbed on the BNNT with satisfactory Eg changes (%ΔE) can be promising candidates for better sensing ability. All calculations are conducted within the density functional theory (DFT) using the ωB97XD functional and 6-31G(d,p) basis set. The present approach incorporates the utilization of empirical atom-atom dispersion in conjunction with long-range correction. The calculations are performed using the quantum chemistry package GAMESS, and the obtained results are visualized by employing the GaussView 6.0.16 program.

Removal of the bemacid blue E-TL using granular activated carbon from abundant biomass: adsorption isotherm, thermodynamic and kinetic studies

In this work, we were interested in the adsorption of an acid dye, Bemacid Blue E-TL by granular activated carbon based on olive stones. To shed light on the adsorption process, batch experiments were performed to study the effect of operating parameters on the adsorption process such as equilibrium time, GAC dose, pH, initial dye concentration, and temperature. The experimental results showed that the adsorption of the dye Bemacid Blue E-TL by GAC based on olive stones depends on the equilibrium time at 8 hours, the pH is 2 of the solution and the dose is 5 g.L-1. To explain the adsorption equilibrium, the experimental values were examined by Langmuir, Freundlich, and Temkin models. The equilibrium is perfectly described by the Langmuir model whose correlation coefficient is higher than 0.99. The maximum retained quantity of the Bemacid Blue E-TL is 55.6 mg.g-1. Different kinetic models such as pseudo-first order, pseudo-second order, and the intraparticle diffusion equation were used to evaluate the adsorption kinetics. The results of the kinetic modeling showed that the pseudo-second order fitted the data well, with a high coefficient of determination (R2 > 0.99) and intra-particle diffusion is not the only rate-limiting step. The thermodynamic parameter values enthalpy (ΔH°), entropy (ΔS°), and energy change (ΔG°) show that the adsorption processes are endothermic and spontaneous. The various results obtained are promising and encouraging to consider a more comprehensive study with the objective of showing that the adsorbent chosen for this study is effective and could be used as a low-cost adsorbent for acid dye removal.

Simultaneous Removal of Cadmium and Disperse Black-9 Dye Using Chemically Modified Rice Husk-Derived Activated Carbon

Heavy metals and organic dyes pose significant environmental concerns due to their persistence, toxicity, and tendency to accumulate in the food chain. These pollutants are often discharged from various industrial sources without proper management, resulting in unacceptable damage to the environment. The use of low-cost agricultural by-products can be a sustainable and green solution for the industrial effluent treatment process. In the present research, the effective removal of Cd2+ and disperse black‒9 (DB‒9) dye simultaneously was planned through the adsorption method utilizing specially activated carbon (AC) derived from rice husk. FTIR, SEM, and XRD were used to characterize the produced AC. The adsorption studies showed that approximately 88% of the dye DB‒9 and 97% of Cd2+ were adsorbed by using optimal dosages of the AC, which were 16 g/L and 12 g/L, respectively. In addition, it was successfully demonstrated that Cd2+ adsorbed AC was capable of binding with DB‒9 and also DB‒9 adsorbed AC is capable of binding with Cd2+. Therefore, a novel strategy for the simultaneous elimination of Cd2+ and DB-9 ideas was successfully implemented in the current study. In addition, equilibrium data were examined to assess the adsorbate-adsorbent system's isotherms. The Langmuir isotherm was determined to be the most well-fitting, with a maximum uptake of 11.48 mg/g. Thermodynamic study (ΔG⁰) showed that the adsorption process was spontaneous, and the adsorption process followed pseudo-second-order kinetics.

Utilizing olive leaves biomass as an efficient adsorbent for ciprofloxacin removal: characterization, isotherm, kinetic, and thermodynamic analysis.

Olive leaves were utilized to produce activated biomass for the removal of ciprofloxacin (CIP) from water. The raw biomass (ROLB) was activated with sodium hydroxide, phosphoric acid, and Dead Sea water to create co-precipitated adsorbent (COLB) with improved adsorption performance. The characteristics of the ROLB and COLB were examined using SEM images, BET surface area analyzer, and ATR-FTIR spectroscopy. COLB has a BET surface area of 7.763 m2/g, markedly higher than ROLB's 2.8 m2/g, indicating a substantial increase in adsorption sites. Through investigations on operational parameters, the optimal adsorption efficiency was achieved by COLB is 77.9% within 60min, obtained at pH 6, and CIP concentration of 2mg/mL. Isotherm studies indicated that both Langmuir and Freundlich models fit the adsorption data well for CIP onto ROLB and COLB, with R2 values exceeding 0.95, suggesting effective monolayer and heterogeneous surface adsorption. The Langmuir model revealed maximum adsorption capacities of 636mg/g for ROLB and 1243mg/g for COLB, highlighting COLB's superior adsorption capability attributed to its enhanced surface characteristics post-modification. Kinetic data fitting the pseudo-second-order model with R2 of 0.99 for ROLB and 1 for COLB, along with a higher calculated qe for COLB, suggest its modified surface provides more effective binding sites for CIP, enhancing adsorption capacity. Thermodynamic analysis revealed that the adsorption process is spontaneous (∆Go < 0), and exothermic (∆Ho < 0), and exhibits a decrease in randomness (∆So < 0) as the process progresses. The ΔH° value of 10.6kJ/mol for ROLB signifies physisorption, whereas 35.97kJ/mol for COLB implies that CIP adsorption on COLB occurs through a mixed physicochemical process.

Immobilizing of polyethyleneimine on bamboo viscose fiber using epichlorohydrin crosslinker for enhancing adsorption ability with lac dye

AbstractImmobilization of polyethyleneimine (PEI) on bamboo viscose fiber using epichlorohydrin (ECH) crosslinker (ABF‐e‐PEI) was employed to enhance the ability of dyeing with lac. The results from morphological observation, thermal degradation behavior, Fourier transform infrared (FTIR) analysis, x‐ray photoelectron spectroscopy (XPS) and x‐ray diffraction (XRD) clearly revealed the success of PEI‐immobilizing on fiber surface with no significant change in intrinsic properties of the fiber after modification. The modified fiber exhibited fast and efficient adsorption with the adsorption capacity &gt;90 mg/g which was much higher than that of the unmodified adsorbent (did not exceed 10 mg/g). The results from kinetic and isotherm studies showed that the adsorption process conformed to the pseudo‐second‐order, intra‐particle diffusion and Langmuir models. Adsorption temperatures have less effect to the adsorption performance of the modified adsorbent. Electrostatic ion‐dipole interaction between protonated amines of PEI and negative charged sites of lac dye was the main proposed mechanism. Good resistance of color changes for ABF‐e‐PEI was confirmed by the color‐fastness assessment (grade 4–5), suggesting efficient method of PEI‐immobilizing using ECH crosslinker. The binding reaction of between amine groups of PEI and hydroxyl groups of the cellulosic fiber using ECH crosslinker can be expected to have a broad potential application in dyeing processes or pollution treatments due to its simple, cost‐effective, flexible and efficient method.

Optimization of the intermediate chamber improves desalination performance in flow electrode capacitive deionization (FCDI): A comparative study

Flow electrode capacitive deionization (FCDI), a novel ion removal technology, is influenced by various factors such as electrode material properties, fluid flow rate, and device structure. In the FCDI system, the intermediate chamber is the core element where ions migrate towards the cathode and anode to complete the adsorption process. In this study, we designed a hollow plastic plate with channels (PP) and a hollow graphite plate with channels (GP) as the intermediate chamber, compare and study with conventional plastic mesh (PM) chambers. CFD simulations revealed that the newly designed PP and GP chambers significantly reduced the hydraulic stagnation zone. The results of the desalination experiments revealed that the desalination efficiency of the GP-FCDI was 1.5 and 1.9 times higher than that of the PP-FCDI and PM-FCDI, respectively. At the same time, in situ potential measurement (ISPM) was used to monitor the voltage drop of each component in FCDI, thereby accurately calculated the proportion of energy consumption in the intermediate chamber. The results indicate that the energy consumption of the intermediate chamber of GP-FCDI was 54 % less than that of PM-FCDI. The current work will help us provide new insights for the design and optimization of FCDI systems.

Structural Characterisation of Zeolites Derived from Lithium Extraction: Insights into Channel- and Cage-Type Frameworks

This study investigates the structural and adsorption characteristics of channel- and cage-type zeolites obtained through lithium extraction. Through XRD, FT-IR spectroscopy, and adsorption isotherm analyses, distinct adsorption behaviours of CH4 and CO2 were observed in both zeolite types. Cage-type zeolites exhibited higher adsorption capacities attributed to their structural advantages, highlighting the importance of structural framework selection in determining adsorbent efficacy. The presence of structural defects and an amorphous phase influenced adsorption behaviours, while thermodynamic data underscored the role of adsorbate properties. Kinetics studies revealed the influence of the structural framework on CH4 adsorption and CO2 adsorption kinetics. Analysis of adsorbate–adsorbent interactions demonstrated robust interactions, particularly with LPM16-Y. These findings offer insights into the potential applications of zeolites in gas adsorption processes, emphasising the importance of structural properties and adsorbate characteristics in determining adsorption performance.

Sustainable Banana-Waste-Derived Biosorbent for Congo Red Removal from Aqueous Solutions: Kinetics, Equilibrium, and Breakthrough Studies

This study investigates the adsorption of Congo red (CR) dye from wastewater using banana peel biochar (BPBC) in both batch and fixed-bed column modes. BPBC was characterized using FTIR, SEM, XRD, TGA, and BET analysis, revealing a predominantly mesoporous structure with a surface area of 9.65 m2/g. Batch adsorption experiments evaluated the effectiveness of BPBC in removing CR, investigating the influence of the BPBC dosage, initial CR concentration, and solution pH. Results showed optimal CR removal at pH levels below 4, suggesting a favorable electrostatic interaction between the adsorbent and the dye. Furthermore, a pseudo-first-order kinetic model best described the adsorption process. The Freundlich isotherm provided a better fit compared to the Langmuir and Dubinin–Radushkevich (D-R) models, implying a heterogeneous adsorption surface. The calculated maximum adsorption capacity (Qm) from the Langmuir model was 35.46 mg/g. To assess continuous operation, breakthrough curves were obtained in fixed-bed column experiments with varying bed heights (1–3.6 cm). The results demonstrated efficient CR removal by BPBC, highlighting its potential for wastewater treatment. Finally, this study explored the feasibility of BPBC regeneration and reuse through four adsorption–desorption cycles.

Ab initio exploration of modified carbon nanotubes as potential corrosion inhibitors

In order to develop novel unexplored potential corrosion inhibitors, covalently modified single-walled carbon nanotubes (SWCNT) via benzoic (–PhCOOH) and aniline (–PhNH2) groups are being investigated as corrosion inhibitors for the first time. Utilizing a comprehensive approach, this study employed density functional theory (DFT), Monte Carlo (MC), and molecular dynamics simulations (MD) to assess the adsorption behavior of modified nanotubes as corrosion inhibitors on the Cu(111) surface within a simulated aqueous HCl corrosion medium. The results provided molecular information on the adsorption capability, geometry adsorption centers, and adsorption energies (Eads) of carbon nanotubes on the surface of Cu(111). The adsorption energy values unveiled robust interactions between SWCNT–PhCOOH and SWCNT–PhNH2 inhibitors and the Cu(111) surface, suggesting a highly effective corrosion protection mechanism. The calculated Eads values exhibited notable ranges, spanning from –260.82 to –308.18 kcal/mol for SWCNT–PhCOOH and –220.92 to –261.01 kcal/mol for SWCNT–PhNH2 with the maximum probability values, representing the most favorable adsorption scenarios, determined to be –292.96 and –229.39 kcal/mol, respectively. A key insight from Monte Carlo simulations underscored the inherent spontaneity of the adsorption process, corroborated by the consistently negative Eads values. These findings collectively underscore the substantial affinity of the inhibitors to the copper surface, contributing to a deeper comprehension of their corrosion inhibition capabilities.

Adsorbent Biomaterials Based on Natural Clays and Orange Peel Waste for the Removal of Anionic Dyes from Water

This study demonstrates the efficient removal of Alizarin Yellow R anionic dye (AY) from aqueous solutions using green adsorbents. Natural kaolin clay (A1), acid-modified natural clay (A2), chemically treated orange peel (C1) and biochar produced by the thermal treatment of orange peel (C2) were tested for the adsorption of AY. The characteristics of the sorbents were determined by instrumental methods: SEM, EDS, FTIR, BET and TGA. The adsorption experiments were performed under different conditions, including the initial AY dye concentration, adsorbent weight, pH, temperature and contact time. The maximum adsorption capacities had values between 15.72 and 74.62 mg/g at 298 K and the optimal pH of 6.5 at initial concentrations ranging from 30 to 70 mg/L for all adsorbents. The equilibrium data were used for the adsorption isotherm models: Freundlich, Langmuir and Temkin. The Freundlich model fit best for the adsorbents A2, C1 and C2, and the Langmuir isotherm had the highest regression value for the adsorbent A1 (R2 = 0.9935). Thermodynamic parameters indicated the spontaneous and favorable adsorption process of AY. A study of the adsorption kinetics proved that they best fit the pseudo-second-order model, with the highest coefficients of determination (R2), outperforming the pseudo-first-order model. The results of this study indicate the potential for the valorization of locally available clays and orange peel waste in the purification processes of water.

α-Fe2O3 nanorods on CoFe-LDH@MX via interfacial interactions for Congo red removal: Experimental and mechanistic studies

Developing a 3D material to support α-Fe2O3 nanorods to improve their adsorption performance for Congo Red (CR) is a major challenge. Herein, a novel 3D composite adsorbent was designed, where 2D material Ti3C2 MX and CoFe-LDH stacked on top of each other as the support material of α-Fe2O3 nanorods (α-Fe2O3@LDH@MX). The specific surface area of the α-Fe2O3@LDH@MX was increased by 2 times (101.28 m2/g) than original CoFe-LDH@MX, thus more favorable for capturing CR (698.25 mg/g). The results of kinetic studies demonstrate that the effective 3D composite structure enables unhindered movement of CR within the α-Fe2O3@LDH@MX. The Langmuir model can accurately describe the adsorption process of CR on the α-Fe2O3@LDH@MX, which means that the process belongs to monomolecular layer chemisorption. Molecular dynamics simulations revealed that the α-Fe2O3 interface primarily interacts with oxygen within the -SO3 group, achieving an adsorption energy up to Einteraction= −20,375.89 kcal/mol. The results of XPS analysis further revealed that interaction between Fe and O achieved the removal of CR. In this paper, the enhancement of α-Fe2O3 adsorption performance has been successfully achieved through innovative structural design. This significantly advances its potential applications and offers new insights for future material design.

Application of Cotton Stalk as an Adsorbent for Copper(II) Ions in Sustainable Wastewater Treatment

The capacity of untreated cotton stalk to remove and adsorb Cu2+ ions in synthetic and natural aqueous solutions was evaluated. The influence of three sensitive parameters of the adsorption process—solution pH, adsorbent dosage, and contact time—on the percentage of Cu2+ removal in agricultural wastewater, livestock wastewater, and synthetic samples was studied. Physicochemical and morphological properties were studied using thermogravimetry, Fourier infrared spectrophotometry, and scanning electron microscopy. The elemental composition, proximal composition, zero charge point, and acid–base sites were determined. In addition, kinetic studies were performed, and the adsorption equilibrium was analyzed. The optimum conditions for Cu2+ adsorption were the following: solution pH = 5.5, adsorbent dosage of 0.6 g, and contact time of 60 min. Under these conditions, the percentage of Cu2+ removal in synthetic samples was 66.5% when the initial copper concentration was 50 mg/L. The removal percentage in agricultural and livestock wastewater samples was 87.60% and 85.05%, respectively, when the initial copper concentration was 25 mg/L. The adsorption data are consistent with the Freundlich isotherm model, which achieved a quadratic fit of 0.991 compared to 0.5542 for the Langmuir model. The experimental results indicate that the adsorption adequately fits the pseudo-second-order kinetic model. The results suggest that cotton stalks are a promising adsorbent for the ecological and economical removal of Cu2+ in wastewater. This research, therefore, provides relevant information that contributes to the sustainable management of agricultural waste and instills hope for a reduction in water pollution from heavy metals derived from agricultural activities.

Preparation of MOR/P(S‐co‐VPh) nanofiber composite membrane and its adsorption properties for rubidium ions

AbstractRubidium (Rb), a rare and precious metal, is widely used in high‐tech fields. In this work the structural advantages of mordenite (MOR) and group affinity of phenolic hydroxyl polymers (poly (styrene‐4‐hydroxystyrene) (P(S‐co‐VPh)) are combined to prepare MOR/P(S‐co‐VPh) nanofiber composite membranes with high selectivity and adsorption specificity for Rb+ by electrospinning. The test results show that MOR is successfully anchored on the nanofiber substrate and maintained its complete crystal structure. Adsorption experiments show that the adsorption capacity of Rb+ increases with the increase of MOR content, and pH = 9.0, T = 25°C are the best adsorption conditions. K+ shows the most obvious interference with the adsorption capacity decreased from 60.03 to 39.33 mg/g. The adsorption process follows with the Langmuir isothermal model and pseudo‐second‐order kinetic equation. The chemical adsorption based on the coordination reaction is the control step, and the intraparticle diffusion also has an important effect on the adsorption rate. The recycling test indicates that the prepared nanofiber composite membrane not only has efficient adsorption of Rb+, but also exhibits excellent regeneration and stability, which helps to achieve its widespread application and long‐term operation in harsh environments.

Artificial neural network-based modeling of Malachite green adsorption onto baru fruit endocarp: insights into equilibrium, kinetic, and thermodynamic behavior

In this study, artificial neural network (ANN) tools were employed to forecast the adsorption capacity of Malachite green (MG) by baru fruit endocarp waste (B@FE) under diverse conditions, including pH, adsorbent dosage, initial dye concentration, contact time, and temperature. Enhanced adsorption efficiency was notably observed under alkaline pH conditions (pH 10). Kinetic analysis indicated that the adsorption process closely followed a pseudo-second-order model, while equilibrium studies revealed the Langmuir isotherm as the most suitable model, estimating a maximum adsorption capacity of 57.85 mg g−1. Furthermore, the chemical adsorption of MG by B@FE was confirmed using the Dubinin–Radushkevich isotherm. Thermodynamic analysis suggested that the adsorption is spontaneous and endothermic. Various ANN architectures were explored, employing different activation functions such as identity, logistic, tanh, and exponential. Based on evaluation metrics like the coefficient of determination (R 2) and root mean square error (RMSE), the optimal network configuration was identified as a 5–11-1 architecture, consisting of five input neurons, eleven hidden neurons, and one output neuron. Notably, the logistic activation function was applied in both the hidden and output layers for this configuration. This study highlights the efficacy of B@FE as an efficient adsorbent for MG removal from aqueous solutions and demonstrates the potential of ANN models in predicting adsorption behavior across varying environmental conditions, emphasizing their utility in this field.

Study on the adsorption mechanism of droplets on parallel flow interfaces in U-shaped microchannels

The adsorption process of deionized water droplets on the parallel flow interface between ionic liquid [BMIM][PF6] and mineral oil is investigated in U-shaped microchannels. Three flow patterns of the efficient adsorption, moderate adsorption, and inefficient adsorption based on the adsorption efficiency were observed. The dimensionless droplet length D/W > 0.72 is conducive to efficient adsorption of droplets. When droplet shape factor β > 1, the lubrication pressure generated within the curved liquid film has a more significant hindrance on the adsorption process, and the reverse lubrication pressure at the outlet of the liquid film is the main reason for the rupture of the liquid film. An increase in the velocity of phase interface A-B movement can lead to an increase in lubrication pressure. A correlation model is established between the dimensionless adsorption length L* and the dimensionless adsorption time t*, and the influence of Laplace pressure is analyzed.

Synthesis of activated carbon from waste polyester fabric activated by ZnCl2 and its adsorption for organic dyes

In order to achieve the resource utilization of waste polyester (WPT), the WPT based activated carbon (WPT-AC) was prepared by ZnCl2 activation high-temperature pyrolysis method. The phase morphology, characteristic groups, pore structure of specific surface area and microstructure were characterized by TGA, XRD, FTIR, BET and SEM. The optimum preparation process of WPT-AC was determined by L9(34) orthogonal experiment, and the adsorption performance of WPT-AC for methylene blue (MB) was evaluated. WPT-AC showed a high specific surface area of 1037.62 m2/g, with rich pore structure, which provided the possibility for efficient adsorption. The pretreatment of ZnCl2 plays a key role in the formation of WPT-AC pore structure, and the abundant pore structure is conducive to improving the adsorption of pollutants. WPT-AC showed excellent performance in the field of organic dye adsorption, and the highest removal rate of MB reached 97.34%. The adsorption was mainly related to electrostatic attraction, hydrogen bonding and π–π conjugation. The analysis of adsorption kinetics and thermodynamics is conducive to a better understanding of the adsorption process.

Thermodynamic and structural investigation of oily wastewater treatment using peach kernel and walnut shell based activated carbon.

Despite the many articles about activated carbon with different precursors in adsorption process, no in-depth research has been carried out to understand the causes of the difference in surface adsorption characteristics of activated carbon with different precursors and different activation processes. In this work, the ability of two active carbon adsorbents made of walnut shell and peach kernel by two chemical and physical methods (totally 4 different types of activated carbon) in treatment of oily wastewater including diesel, gasoline, used oil or engine lubricant has been compared. The results show that the chemical activated peach carbon active with 97% hardness has provided the highest hardness and physical activated walnut carbon active has obtained the lowest hardness value (87%). It is also found that peach activated carbon has a higher iodine number than walnut activated carbon, and this amount can be increased using chemical methods; Therefore, the highest amount of Iodine Number is related to Peach activated carbon that is made by chemical method (1230 mg/g), and the lowest amount of iodine number is seen in walnut activated carbon that is made by physical method (1020 mg/g). moreover, the pore diameter of physical activated carbon is lower than chemical activated carbon in all cases. So that the pore diameter of chemical activated peach carbon active is equal to 22.08 μm and the measured pore diameter of physical activated peach carbon active is equal to 20.42 μm. These values for walnut are obtained as 22.74 μm and 21.86 μm, respectively. Furthermore, the temperature and pH effects on the adsorption of different synthesized oily wastewater was studied and it was found that a decrease in adsorption can be seen with an increase in temperature or decreasing the pH value, which can be referred to this fact that the process of adsorption is an exothermic process. Finally, to analyze the compatibility of adsorption isotherms with experimental data and to predict the adsorption process, three different isotherms named Langmuir, Temkin, and Freundlich isotherms were applied and their parameters were correlated. The correlation results show that the Langmuir isotherm had the best correlation in all cases compared to the Freundlich and Temkin isotherms, based on the correlation coefficient, and the calculated R2 values which was greater than 0.99 in all the studied cases.

Degradation of pharmaceuticals and other emerging pollutants employing bi-metal catalysts/magnesium and/or (green) hydrogen in aqueous solution.

Contaminations by pharmaceuticals, personal care products, and other emerging pollutants in water resources have become a seriously burgeoning issue of global concern in the first third of the twenty-first century. As societal reliance on pharmaceuticals continues to escalate, the inadvertent introduction of these substances into water reservoirs poses a consequential environmental threat. Therefore, the aim of this study was to investigate reductive degradation, particularly, catalytic hydrogenation regarding model pollutants such as diclofenac (DCF), ibuprofen (IBP), 17α-ethinylestradiol (EE2), or bisphenol-A (BPA), respectively, in aqueous solutions at lab scale. Iron bimetals (zero valent iron, ZVI, and copper, Cu, or nickel, Ni) as well as zero valent magnesium (Mg, ZVM) in combination with rhodium, Rh, or palladium, Pd, as hydrogenation catalysts (HK), were investigated. Studies were executed through various short-term batch experiments, with multiple sample collections, over a total range of 120min. The results indicated that DCF was attenuated at over 90 % when exposed to Fe-Cu or a Fe-Ni bimetal (applied as a single model pollutant). However, when DCF was part of a mixture alongside with IBP, EE2, and BPA, the attenuation efficacy decreased to 79 % with Fe-Cu and 23 % with Fe-Ni. Conversely, both IBP and BPA exhibit notably low attenuation levels with both bimetals, less than 50 %, both deployed as single substances or in mixtures. No reaction (degradation) products could be identified employing LC-MS, but sometimes a release of the parent pollutant when applying an acetic acid buffer could be noted to a certain extent, suggesting adsorption processes on corrosion products such as iron hydroxide and/or oxides. Surprisingly, Mg in combination with Rh (Rh-HK) or Pd (Pd-HK) showed a significantly rapid decrease in the concentrations of DCF, EE2, and BPA, in part up to approximately 100 %, that is, within a few minutes only in part due to hydrogenation degradation reactions (related reaction products could actually be identified by LC-MS; adsorption processes were not observed here). Moreover, kinetic modeling of the DCF degradation with Mg-Rh-HK was conducted at different temperatures (15 °C, 20 °C, 25 °C, 35 °C) and varied initial concentrations (2.5mg/L, 5.0mg/L, 7.5mg/L, 10.0mg/L). The outcomes prove that the degradation of DCF at the Rh-HK's surface followed a modified first-order kinetics, most probably by catalytic hydrodehalogenation and subsequent hydrogenation of the aromatic moieties (molecular hydrogen was provided by the corrosion of Mg). From the determined reaction rate constants at four different temperatures, the activation energy was estimated to be 59.6kJ/mol by means of the Arrhenius equation what is in good agreement with similar results reported in the literature. This coupled hydrodehalogenation and hydrogenation approach may be upscaled into a new promising technical process for comprehensively removing such pharmaceuticals and similar pollutants in sewage plants in a single step, furthermore, even in combination with adsorption by activated carbon and/or ozonation which have already been established at some sewage plants in Switzerland and Germany recently.

Durian peel (Durio zibethinus) utilization as an adsorbent in the purification of acidified crude glycerol

Durian (Durio zibethinus) is highly consumed seasonal fruit that generates abundant waste in the form of peel. Durian peel can serve as an effective adsorbent because it is rich in cellulose–lignin. This waste has potential applications in the chemical industry, such as using durian peel to purify crude glycerol. This research studied durian peel as an adsorbent in the form of activated carbon in the purification of acidified crude glycerol. The purification process begins with the acidification process of crude glycerol using concentrated acid with a mole ratio of phosphoric acid:glycerol (n/n) of 0.5:1, 1:1, 1.5:1, 2:1, and 2.5:1. The adsorption process by carbonization and activated of durian peel using 0.1 N KOH as adsorbent with a mass percentage ratio of adsorbent:crude glycerol (%wt) of 5 %, 10 %, 15 %, 20 %, and 25 %, and stirred using a magnetic stirrer at a speed of 250 rpm for 2 h. The adsorbent utilized has a carbon-rich content of as much as 80.6 % based on Energy Dispersive X-ray analysis. The highest glycerol purity obtained at 96.26 % is achieved at phosphoric acid:glycerol mole ratio of 1:1 and adsorbent:glycerol mass ratio of 25 %. This result also matches the analysis by gas chromatography. Thus, the others test of the purified glycerol, such as density of 1.267 g/cm3, water content of 1.6 %, ash content of 0.2 %, and matter organic non-glycerol of 1.94 %, are in accordance with the glycerol standard BS 2621:1979.

Cu (II)-based metal-organic framework functionalized with graphene oxide as a sorbent for the dispersive micro-solid-phase extraction of losartan potassium from water

AbstractIn this study, a new metal–organic framework (MOF) based on copper (II) functionalized with graphene oxide (MOF-Cu@GO) was successfully synthesized and applied as an efficient sorbent for dispersive micro-solid phase extraction (D-μSPE) of losartan potassium (LP) from water. The MOF-Cu@GO sorbent was characterized using DRX, FTIR, XPS, TGA, RAMAN, BET, SEM, EDX, and potential Z. The influence of different parameters in the D-μSPE method was studied and optimized using the fractional factorial design 25–1 and central composite design. The results indicated that the adsorption process was spontaneous and endothermic followed the pseudo-second order model kinetics and the Freundlich isotherm. The maximum adsorption capacity of MOF-Cu@GO sorbent was 415 mg g−1. The adsorption mechanism proposed of LP onto MOF-Cu@GO proceeded via electrostatic interaction, hydrogen bonds, unsaturated sites of the ligand, and π-π interactions. The microextraction procedure was followed by determination of LP with high performance liquid chromatography (HPLC–UV-Vis). Under optimized conditions, the limits of detection and quantitation were found to be 25 and 80 ng ml−1 respectively, the method exhibited a linear response (r = 0.998) in the concentration range of 0.1–50 µg ml−1 of LP, with a relative standard deviation less than 2% (n = 5). The D-μSPE method showed preconcentration factor of 684.9 and high percentage of LP extraction of 99.78% ± 2.62, the accuracy of the method was demonstrated by studying the recovery of LP from water samples of 100.3 ± 1.06. The material obtained can be used up to 3 cycles with time for the sorption and determination of 30 min indicating good stability and reusability. The MOF-Cu@GO proposed is an efficient and fast sorbent in the D-μSPE for determination of LP from aqueous solutions.