Adsorption Amount Research Articles

Enhancement of the Cytokine Adsorption Capacity of Octacalcium Phosphate by Interaction-Controlled Glycosaminoglycan Modification to Promote Osteoblastic Differentiation.

This study was designed to investigate how the strength of the interaction between octacalcium phosphate (OCP) and modified chondroitin-A sulfate (CS-A), a glycosaminoglycan, regulates the adsorption-desorption of cytokines and subsequently affects the osteoblastic differentiation of mesenchymal stem cells (MSCs) in vitro. The utilization of cytokines produced by cells, such as macrophages, stimulated by the hydrolysis of OCP, is expected to enhance the bone regeneration capacity of the OCP. CS-Na was used to modify CS-A on the OCP immobilized with the amino group through electrostatic interactions. On the other hand, N-hydroxysuccinimide (NHS)-esterified CS-A was used to form the covalent bond between CS-A and the amino group on the surface of OCP. X-ray diffraction and Raman spectroscopy indicated that the CS-A-modified OCP maintained its structure, regardless of the modification process. The remaining ratio of the modified CS-A in the buffer suggests that increasing the immobilized density of the amino group and the modification using NHS ester may enhance interaction strength between OCP and CS-A. The adsorption amount and retention rate of recombinant human bone morphological protein-2 (rhBMP-2, an endogenous cytokine model) increased onto CS-A-modified OCP under physiological conditions when the interaction strength between OCP and the protein was stronger. The higher interaction strength between the OCP and CS-A could be associated with the enhanced adsorption affinity for the lower-molecular-weight basic protein. The alkaline phosphatase activity of MSCs increased depending on the remaining rate of rhBMP-2 adsorption on the CS-A-modified-OCP. Fourier transform infrared spectroscopy and chemical analysis indicated that the hydrolysis of the OCP progressed regardless of CS-A modification after MSC incubation. The present study suggests that stronger interactions between the OCP and glycosaminoglycans could contribute to the capture and retention of endogenous cytokines on the surface to further promote osteoblastic differentiation under the chemical environment induced by the hydrolysis of the OCP.

Thiol-Functionalized Cobalt Ferrite (CoFe2O4@MPTS) Nanoparticles as Cutting-Edge Adsorbents for Bovine Serum Albumin.

This paper describes the synthesis of CoFe₂O₄ nanoparticles via a simple ultrasonic-assisted co-precipitation method and their functionalization with thiol groups using (3-Mercaptopropyl)trimethoxysilane (MPTS) as the functionalizing agent. The use of ultrasonic energy not only serves as a green energy source but also reduces the reaction time fivefold compared to conventional methods. The synthesized CoFe₂O₄ nanoparticles were characterized for their surface and internal properties using instrumental techniques such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Vibrating Sample Magnetometer (VSM). The functionalized nanoparticles were applied for the effective adsorption of bovine serum albumin (BSA) from a buffered aqueous medium. To enhance the adsorption performance, the influence of pH, amount of solid adsorbent, initial BSA concentration, shaking time, and temperature on protein adsorption was investigated. Lagergren pseudo-second-order adsorption kinetics fitted the BSA adsorption data well, with an acceptable R² value of 0.976. Additionally, the BSA adsorption data were analyzed using Langmuir and Freundlich isotherm models, and it was concluded that the experimental data followed the Langmuir equation more closely than the Freundlich equation. At an initial pH of 5.57 (acetate buffer), the adsorption capacity (Q₀) for BSA protein was found to be 200mg/g. The thermodynamic study revealed ΔS° and ΔH° values of 17.40J/mol·K and - 45.37kJ/mol, respectively.

Exploration of BSA imprinting mechanism by fluorescence anchoring and host–guest interactions

AbstractFor protein imprinting, template molecule anchoring and imprinting site recognition are very important processes. Herein, we have proposed for the first time to use photo‐switchable host–guest interactions between α‐cyclodextrin (α‐CD)‐modified bovine serum albumin (BSA) and azobenzene coated organic covalent framework (COF) to immobilize and elute proteins. A novel surface labeled polymer microspheres (COF‐MIPs) were constructed, which could reduce the mass transfer resistance and accelerate the adsorption process, resulting in the adsorption equilibrium reaching 60 min and the saturated adsorption amount of 563.86 mg/g. Additionally, using guest molecules (azobenzene) to label the imprinted sites allows the correlation of the relationship between the fluorescence intensity and the protein adsorption process. The fluorescence analyses show that the material exhibits excellent adsorption specificity, with imprinting factors greater than 4. This work extended the application of the host–guest interaction between cyclodextrin and azobenzene and provides a new approach for developing protein‐imprinting materials.

Removal of Pb(II) from aqueous solution using xanthate modified waste walnut shells

A vast number of biomass-based materials are getting increasing attention for heavy metal removal and recovery due to their good performance, low cost, large availability, and environmental friendliness. This study primarily aims to fabricate a cost-effective, potent adsorbent derived from walnut shells through chemical modification, targeting the removal of Pb(II) ions from water. The experimentation involves the preparation of adsorbents from charred walnut shell (CWS) and xanthated walnut shell (XWS), followed by batch trials to eradicate Pb(II) from water. Parameters for instance pH, concentration of Pb(II), adsorbent quantity, and contact duration were examined using both CWS and XWS adsorbents. For characterization purposes, FTIR, XRD, and FE-SEM analyses were employed. Optimal conditions were identified at pH 4 and duration of contact 150 minutes for both adsorbents. Equilibrium sorption data adhered best to the Langmuir isotherm model, with maximum adsorption capacities of 61 mg/g for CWS and 109.9 mg/g for XWS. Kinetic modeling showed the well-fitting of pseudo-second order kinetic. These findings suggest that XWS presents a promising, eco-friendly alternative bioadsorbent intended for the elimination of lead (II) from water.

Reevaluation of the Suitability of 129Xe Nuclear Magnetic Resonance Spectroscopy for Pore Size Determination in Porous Carbon Materials.

Xenon isotope nuclear magnetic resonance (129Xe-NMR) spectroscopy has been widely used to evaluate the pore structure of materials. However, determining how to apply this technique to investigate porous carbon materials is sometimes challenging, partly due to the structural disorder and heterogeneity of the surface properties of these materials, and partly due to the lack of reliable methods for controlling and assessing the density of adsorbed Xe. In this study, we designed and constructed a temperature- and pressure-controllable 129Xe-NMR system to evaluate the interaction between activated carbon (AC) and adsorbed Xe molecules. Based on a confirmation of surface-covering adsorption form of Xe molecules in AC pores, the extrapolation to the ordinate in plots of the surface area-normalized Xe adsorption amount (ρXe) and measured 129Xe-NMR chemical shifts of adsorbed Xe molecules, δ(Xe), to remove the influence of the Xe-Xe interaction allowed us to estimate the interaction between the AC pore surface and a single Xe molecule. These data confirmed that interactions between the pore surface and adsorbed Xe molecules depend on a parameter related to the AC pore size, regardless of the content of oxygen-containing surface functional groups, and an empirical equation to estimate the average pore size of ACs from the 129Xe-NMR results was proposed. Downward deviations of the linear correlation between ρXe and δ(Xe) were attributed to the influence of paramagnetism presumably derived from oxygen-containing functional groups on the surfaces of ACs and to changes in the adsorption form in low- and high-ρXe regions, respectively. These findings confirm the suitability of 129Xe NMR for pore size determination in porous carbon materials.

A Cu/β-cyclodextrin/reduced graphene oxide nanocomposite for efficient and multi-aflatoxin detection in rice, ginger and bean samples.

Aflatoxins (AFs) are some of the most important mycotoxins or fungal toxins that cause contamination of food products and are considered a threat to human and animal health. An efficient Cu/β-cyclodextrin/reduced graphene oxide nanocomposite (Cu/β-CD/rGO) has been prepared and applied as a new solid-phase extraction adsorbent for the separation and preconcentration of four AFs (B1, B2, G1, and G2) using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The successful synthesis of the prepared nanocomposite was confirmed using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The impacts of pH, amount of adsorbent, sample volume, desorption solvent volume, and salt concentration on the recovery of AFs were precisely investigated and optimized by central composite design (CCD). Under the optimal conditions, the introduced method demonstrated good linearity in the range of 0.4-5.4, 0.08-1.08, 0.4-5.4, and 0.08-1.08 ng g-1 for AFs B1, B2, G1 and G2, respectively. The limits of detection and quantification for the four AFs were obtained in the range of 0.06-0.53 and 0.20-1.62 ng g-1, respectively. The accuracy of the method was evaluated using recovery measurements in spiked real samples such as rice, bean, and ginger samples, and satisfactory recoveries were obtained in the range of 83.5-109.0% with good precision (RSDs between 2.4 and 8.6%). The results of this research revealed that our developed method is sensitive, highly effective, and convenient to perform for the trace analysis of AFs in different real samples.

Molecular Simulation of Adsorption of CO2 from a Combustion Exhaust Mixture of Zeolites with Different Topological Structures

In this work, a molecular simulation method was used to study the adsorption of seven combustion products (CO2, H2O, SO2, N2, O2, NO and NO2) on three zeolites with different topological structures (4A, MIF and MOR). Adsorption isotherms of pure components and mixtures at a wide range of temperatures (253–333 K) were calculated using the Monte Carlo method, obtaining equilibrium parameters including the adsorption capacity, adsorption heat and energy distribution. The calculation results indicated that 4A zeolite with more micropores has a stronger adsorption performance for CO2. The presence of water significantly reduced the CO2 capture efficiency of the three zeolites, and the CO2 adsorption amount decreased by more than 80%. Adsorption kinetics was studied using the molecular dynamic (MD) method, MFI and MOR, with channel-type pore structures exhibiting stronger gas diffusion performance, though their separation efficiency was not high. A 4A zeolite has the potential for kinetic separation of CO2.

Vortex-assisted dispersive solid-phase microextraction of manganese in food samples by using newly synthesized biodegradable poly (3-hydroxy butyrate) diethanol amine

A newly synthesized biodegradable polyhydroxy butyrate diethanol amin (PHB-DEA) was used as adsorbent for vortex assisted dispersive solid phase microextraction (VA-dSPµE) of manganese in food samples. The different parameters were optimized such as pH, amount of adsorbent, time, desorption solvents and time and also number of reuses. After the sample preparation step, the determination of manganese from food samples was carried out using flame atomic absorption spectrometry. The present developed method showed good LOD value 0.15ngmL-1 and LOQ 0.5ngmL-1. The 0.5-300ngmL-1 linearity range was found and enhancement factor was 182. The inter-day RSD% was 2.2-4.1 and intra-day RSD% was 2.8-5.2. The recovery of manganese was found in the 95-98% range. The factorial design was employed such as response surface plots, pareto chart, residual plots and ANOVA was applied to estimate the significant level of the model using central composite design (CCD). The developed VA-dSPµE procedure was successfully implemented to determine manganese in food samples.

Cysteine-coated Magnetite Nanoparticles for the Removal of Carmoisine Edible Dye from Aqueous Medium.

In this study, cysteine-coated magnetite nanoparticles (Fe3O4@Cys MNPs) were synthesized by chemical method and applied as a recoverable and efficient adsorbent for the removal of carmoisine dye from aqueous solutions. The synthesized MNPs were characterized by FT-IR, XRD, SEM, and TEM studies. The effect of various experimental parameters on the dye removal efficiency was studied using Taguchi orthogonal array design (L16 array). Under the optimum conditions (pH = 2, stirring time = 30 min, adsorbent amount = 0.1 g and without salt addition), more than 92% of carmoisine was removed from the aqueous solutions. The kinetic studies showed rapid adsorption dynamics by a pseudo second-order kinetic model, confirming that diffusion controls the adsorption process. Dye adsorption equilibrium data were fitted well to the Freundlich isotherm, and the synthesized adsorbent showed high removal efficiency. The obtained results showed that the synthesized MNPs act as a reusable adsorbent for carmoisine removal with an easy procedure.

Adsorption of malachite green using waste marine cuttlefish bone powder: Experimental and theoretical investigations.

Adsorption remediation is an energy-efficient water treatment technology that utilizes the adsorption properties of a biosorbent to remove various pollutants. While many articles have explored the high surface area and adsorption capacity of activated carbon for remediating aquatic systems, few have delved into the environmental impact of its synthesis, which often involves H3PO4, a highly toxic activating agent. In this study, we present a groundbreaking alternative to activated carbon for the adsorption and remediation of aquatic waste that doesn't rely on chemical products. Our discovery that cuttlefish bone, typically considered waste, can serve as an effective adsorbent is a significant leap in eco-friendly research and a source of inspiration for future sustainable solutions. We selected Malachite Green (MG) as a cationic toxic dye to evaluate the adsorption capacity of our green adsorbent. The prepared powder underwent characterization using techniques such as FTIR, XRD, SEM, and elemental analysis. Additionally, the determination of the cuttlefish bone's zero-point charge pH revealed a value of 8.4, which influences the material's surface charge and its interaction with ions and molecules in the solution. We conducted a detailed study on the effects of solution pH, adsorbent amount, Malachite Green concentration, temperature, and contact time on the dye adsorption. The results demonstrated that the adsorption of Malachite Green by cuttlefish bone powder is an endothermic process, requiring heat input. This indicates that the adsorption efficiency increases with temperature. The significant enthalpy results obtained confirmed the endothermic nature of the process. In this study, we combined experimental and theoretical approaches to gain a better understanding of the adsorption mechanism. The results showed that Cuttlefish Bone is an environmentally friendly and highly efficient adsorbent.

Design and synthesis of a new recyclable nanohydrogel based on chitosan for Deltamethrin removal from aqueous solutions: Optimization and modeling by RSM-ANN.

In this study, a new magnetic biocompatible hydrogel was synthesized as an adsorbent for Deltamethrin pesticide removal. The optimal conditions and adsorption process of Deltamethrin by chitosan/polyacrylic acid/Fe3O4 nanocomposite hydrogel was studied by Response Surface Methodology by Central Composite Design (RSM-CCD) and Artificial Neural Network (ANN). This adsorbents were synthesized, and then characterized and investigated using FT-IR, XRD, FE-SEM, EDX, Map, VSM, and TGA methods. The results of these analyses showed that the nanocomposite hydrogel was well synthesized and has the ability to adsorb the Deltamethrin pesticide. The results obtained through analysis using response surface methodology showed that the maximum amount of adsorption was 99.79% at 26°C, while pH, initial concentration, contact time, and adsorbent dose were 7, 22ppm, 90min, and 1.3g/L respectively. Comparison between results obtained from CCD modeling and artificial neural network proved that both methods had high ability to predict the adsorption process but the CCD method had higher coefficient of determination and lower error. The equilibrium and kinetic study of the process showed that the Toth isotherm model, pseudo-second-order is all suitable for expressing the adsorption process. In addition, the adsorption mechanism followed double-exponential model that combines external and internal diffusions. Results of Thermodynamic study suggested that the Deltamethrin adsorption on CS/PAA/Fe3O4 was a spontaneous and exothermic process. The results of the equilibrium process study revealed that the adsorption process was physical and desirable, therefore, the adsorption-desorption process was performed which showed that the composite was reusable up to 10cycles.

Construction of low-vacancy hexagonal Prussian blue analogues for efficient rubidium recovery

Prussian blue analogues (PBAs) are considered a promising adsorbent for rubidium recovery due to their high ion exchange capacity and selectivity. However, the development of PBAs-based rubidium adsorbents with excellent stability and adsorption capacity is still hindered by the inevitable CN ligand vacancies. Herein, a synthetic strategy is proposed to slow down crystal nucleation and promote the self-repair of crystal defects by incorporating N-doped porous carbon (NPC) as a solid modifier during the synthesis process. As a result, the vacancy content of Zn-PBA-NPC is significantly decreased and large size twinned crystals are produced, which remarkably improves the thermal and acid-base stability. Benefiting from the high content of K+ in the low-vacancy Zn-PBA-NPC, it achieves a high adsorption amount of 199.1 mg/g and rapid adsorption kinetics of just 5 min for Rb+. In addition, it shows good selectivity in the presence of other alkali metal ions. This work not only prepares a high-performance adsorbent for efficient recovery of Rb+, but also facilitates insights into the design and construction of low-vacancy PBAs.

Fast and effective adsorption of Ce3+ by phosphate-functionalized ZIF-67-derived layered double hydroxides

In this experiment, phosphate (sodium hexametaphosphate) was used as an intercalation modifier and ZIF-67 as a precursor mixed with Al(NO3)3·9H2O Nanolayered double hydroxides P-Co-Al-LDH with hexametaphosphate group intercalation were prepared in a hydrothermal environment and characterized by SEM, FT-IR, XRD, TGA, SEM and XPS. The adsorption performance of P-Co-Al-LDH and control Co-Al-LDH on Ce3+ under different adsorption conditions was firstly investigated by optimization experiments. It was determined that the best adsorption effect of P-Co-Al-LDH was achieved at pH=6, and the fast equilibrium adsorption state was achieved within 30 min, with the adsorption amount reaching 220.98 mg/g and the adsorption efficiency reaching 72.66%. In addition, kinetic, isothermal adsorption and thermodynamic modeling explored the adsorption mechanism of Ce3 + by nanodiamond P-Co-Al-LDH mainly the complexation of functional groups in sodium hexametaphosphate with metal ions greatly improved the adsorption performance. Several regeneration experiments were carried out to evaluate the stability and reusability of the adsorbent. After three cycles of adsorption, the adsorption efficiency was still maintained at 83.26%.

Photochromism in the periodic nanospace of zeolite LTA by the transfer of photoexcited electrons of adsorbed Na atoms.

Cationic sodium (Na) clusters incorporated into a dehydrated Na-form LTA (Na-LTA) zeolite by the adsorption of Na atoms exhibit diamagnetism regardless of their adsorption amount. These clusters preferentially form in β-cages under the condition of dilute adsorption. In this study, photochromism was observed on the dilute Na-adsorbed Na-LTA, which showed a color change from yellow-green to dark blue-green at room temperature. This phenomenon resulted in dissociation of the diamagnetic Na clusters in β-cages upon light irradiation and thereby in the formation of two metastable Na43+ clusters with C3v symmetry in α-cages from the photoabsorption and electron spin resonance spectra. We also observed photochromism in a sample of insufficiently dehydrated Na-LTA with dilute Na adsorption-i.e., the initial white color changed to blue, then blue-green and finally dark moss-green upon irradiation with UV light. This phenomenon consists of two steps. First, products in the β-cages, formed by the reaction of residual water molecules with adsorbed Na atoms, release electrons upon irradiation. The electrons transfer to the α-cages, forming the metastable Na43+ clusters. Next, the diamagnetic Na clusters are formed in vacant β-cages by the thermal transfer of electrons from the Na43+ clusters in the α-cages. Na clusters including multiple electrons were also formed in the α-cages by long exposure to UV light irradiation, which had a similar effect to increasing the adsorption amount of Na atoms onto the dehydrated Na-LTA. After termination of irradiation, the sample required a week to change its color to light yellow.

A novel eco-friendly depressant Scutellaria Baicalensis Extract SBE and its performance on flotation separation of chalcopyrite from sphalerite: A combined experimental and mechanism investigation

This research investigates the utilization of Scutellaria Baicalensis Extract (SBE) as a depressant in the flotation separation of sphalerite and chalcopyrite with Potassium Amylxanthate (PAX) serving as the flotation collector. The feasibility of SBE as a sphalerite depressant at near neutral pH conditions was evaluated through flotation tests, and its depression mechanism was explored using contact angle measurements, zeta potential measurements, adsorption measurements and XPS analyses. Micro-flotation experiments demonstrated the efficacy of SBE as a sphalerite depressant. In artificial mixed mineral experiments, a Cu concentrate with a recovery of 92.55 % and a grade of 28.45 % Cu, and a Zn concentrate with a recovery of 94.43 % and a grade of 57.30 % Zn were obtained at an SBE concentration of 37.5 mg/L. Contact angle, zeta potential and adsorption measurements revealed that SBE was adsorbed onto both sphalerite and chalcopyrite surface, with stronger adsorption on sphalerite. The amount of SBE adsorption on sphalerite exceeded that on chalcopyrite, and SBE prevented the collector’s adsorption on sphalerite while minimally affecting chalcopyrite. XPS analysis results suggested that SBE likely acts through physical adsorption on the mineral surface.

Influencing Factors and Ecological Risks of Organochlorine Pesticide Adsorption in Surface Sediments of Qingshui River

ABSTRACT Taking the first-level tributary of Ningxia section of the Yellow River (Qingshui River) as the study area, surface sediment samples were collected during the seasons in 2018. The distribution characteristics, pollution levels, possible sources, influencing factors, and ecological risks of organochloride pesticides (OCPs) in the surface sediments were studied. The detected mean amounts were n.d. ~10.640 (1.474) ng·g−1, and the detection rate was 80.95%. The content (mean values) of Hexachlorocyclohexanes (HCHs), Endosulfan, Chlordane, and Dichlorodiphenyltrichloroethane (DDT) with higher detection amounts and detection rates were n.d. ~0.949 (0.153), n.d. ~1.973 (0.331), n.d. ~0.271 (0.052), and n.d. ~10.583 (0.819) ng·g−1, respectively. The total OCP amounts were detected in Changshantou and Liwang research sections, which have surrounding farmlands and low water flow. The total organic carbon plays a vital role in the residue and distribution of β-HCH and Dieldrin. In a high-salinity environment, the lower-layer sediments had higher adsorption efficiencies for DDT and γ-HCH and the HCH content decreased with the increase in pH. The total nitrogen and phosphorus in sediments were among the controlling factors affecting the distribution of Endosulfan II and p,p’-DDT, respectively, but their effects on Dieldrin only appeared in the spring flood season. Further, a functional model was established with respect to the adsorption amount of various OCPs and the influencing factors. The component analysis results showed that OCPs primarily originated from historical residues; however, only small amounts of Lindane, Dicofol, Endosulfan, and Chlordane compounds have been observed recently in the local environment. Using the low-effect interval and median method for potential ecological risk assessment, Endosulfan was noted to have potential ecological risks, mainly distributed in the middle and lower reaches of the river. The reasons for the potential harm require attention and further research.

Mathematical Expression and Prediction of VOCs Adsorption Capacity and Isotherm.

Adsorption capacity prediction, which needs to be based on the precise structure-capacity relationship, is important for better adsorbent design. However, the precise adsorption contribution coefficients of pores of different sizes for volatile organic compound (VOC) adsorption remain unclear. Herein, a control variable method is employed as a generative model to realize the numerization of the precise structure-capacity relationship. For the first time, a concise equation is proposed that can predict the adsorption capacities/isotherms of unknown adsorbents through their pore structure parameters. Interestingly, practical VOC adsorption amounts aligned with predicted values obtained by simultaneously considering pore volume (which undergoes volume-filling adsorption) and surface area (which undergoes surface-covering adsorption) as input variables. Derivation of the equation is based on classical adsorption theories and mathematical expression of the precise structure-capacity relationship obtained from actual experimental results. Each parameter in the equation has a specific physical meaning. This unprecedented VOC adsorption capacity/isotherm prediction method provides in-depth insight for accurate quantification of VOC adsorption, with great potential for gas adsorption prediction and guidance in the development of adsorption materials and technologies.

Interweaving two dimensional mesoporous covalent organic frameworks for efficient removal of mercury from aqueous solution

The current study defines the ultrasound-assisted solvothermal synthesis of covalent organic frameworks (COFs) using a combination of 4,4′-diaminobiphenyl and trialdehyde (BDTA-COF). The X-ray diffraction (XRD) studies confirm the formation of COF, which aligns better with AA stacking than AB stacking. The morphology of the formed COFs is a flower-like structure. The Fourier transform infrared spectroscopic (FTIR) results show that imine linkages are forming and that the aldehayde and amine peaks are not present. The formed BDTA-COF was found to be mesoporous and exhibit 2.4 nm pore size with 472 m2g−1 surface area. BDTA-COF has been evaluated for the effective removal of Hg+ from an aqueous solution through adsorption. Maximum adsorption efficiency (99 %) was achieved by optimizing the parameters like selectivity of metal, concentration, pH, amount of adsorbent. The nitrogen atoms from the imine linkages and the oxygen atoms in BDTA-COF are the primary active sites for effective adsorption of Hg⁺. The adsorption kinetics control the chemisorption of Hg+ with the BDTA-COF's imine group since the results fit well with the pseudo-second-order model. Among the various isotherm models, the BDTA-COF/Hg+ system followed the Langmuir model and insists on the monolayer adsorption phenomena. After adsorption, the XRD shows a slight change in peak positions, and the SEM image indicates the deposition of micrometer-sized particles onto the BDTA-COF. After adsorption, FTIR and X-ray photoelectron spectroscopic (XPS) tests show the interaction of functional groups of BDTA-COF and Hg+. High surface area, covalency, porosity, ordered confinement, imine linkages and stability of COFs could be the reasons for good adsorption efficiency and need additional tuning for practical applications for adsorption removal of pollutants from water.

Carboxylic acid-based fuel mediated sustainable one-pot fabrication of CaFe2O4 with enhanced adsorptive elimination of hazardous dye

The present work successfully demonstrated the morphological variation of CaFe2O4 (CFO) concerning various fuels (carboxylic acid groups contain compounds) using a one-step combustion technique. The SEM analysis of the CFO suggests the formation of sharp-edge rocky crystals to highly agglomerated porous clumps concerning the role of fuel. The x-ray diffraction analysis suggests that all samples of CFO are nanocrystalline orthorhombic structure constituted <50 nm. The BET and EDX analysis discloses that CFO s surface area and element composition is highly depend on the fuel molecule (reducer). The CFO performs efficacious in the adsorptive removal of hazardous dye Acid Fuchsin (AF) from an aqueous medium in a slightly acidic environment (pH 6). The AF removal was engaged with the batch adsorption method and optimized the process’s essential parameters (amount of adsorbent, initial AF concentration, and time) were optimized to achieve the utmost efficiency. The AF adsorption was well described by the Langmuir isotherm with outstanding adsorption capacity in the order of CFO-OA (Oxalic acid) (866) < CFO-TA (Tartaric acid) (1063) < CFO-CA (Citric acid) (1504) < CFO-MA (Malonic acid) (1656 mg/g). The adsorption energies were estimated from the Dubinin-Radushkevich model, indicating that adsorption occurs via the chemical process. The pseudo-second-order (PSO) kinetic model was better at explaining the uptake of AF, and the Intraparticle diffusion model indicated that pore diffusion was the rate-controlling step. The reusability test shows that the CFO has high efficiency up to five regeneration cycles. Thus, the work suggests that CFO could be an eco-friendly, cost-effective alternative adsorbent for wastewater treatment.

Effect of Fe3+ on sulfidation flotation behavior of anglesite from zinc leaching residue

The recovery of anglesite (PbSO4) from zinc leaching residue (ZLR) via flotation is a valuable research topic. In practical production, Fe3+ is inevitably present in the anglesite flotation from ZLR. In this study, the effect of Fe3+ on the sulfidation-xanthate flotation of anglesite was investigated by flotation tests. Micro-flotation results indicated that the anglesite flotation was depressed with Fe3+ pretreatment. The xanthate adsorption quantity, zeta potential, XPS, and FTIR measurements revealed that hydrophilic FeOOH species was adsorbed on the surface of the anglesite, thereby inducing the reduction of xanthate adsorption quantity. The bench-scale flotation results indicated that Fe3+ concentration in slurry decreased from 658.57 to 29.46 mg/L with acid washing ZLR three times. Consequently, Pb grade and recovery were increased from 9.91 % to 20.43 % and from 37.63 % to 67.74 %, respectively. These results might have guiding significance for the practical application of anglesite flotation from ZLR.