Adsorption Temperature Research Articles

Utilization of Ketapang Seed Shells in Reducing Pb(NO<sub>3</sub>)<sub>2</sub> Metal Levels by Adsorption Process

Industrial wastes such as lead metal can cause serious problems because of their toxic nature and can pollute the environment. To reduce levels of lead metal, you can use a natural adsorbent from activated charcoal on the outer shell of ketapang seeds. The ketapang tree is a type of plant that is often found in the surrounding environment because it is used as a shade for the many falling ketapang seeds making waste in the environment to reduce environmental pollution from the falling ketapang can be used as an adsorbent because it contains cellulose and carbon elements. One alternative to reduce lead levels using adsorbents is through the adsorption process which is the process of adsorption of a solid or liquid that involves physical, chemical and electrostatic interactions between the adsorbate and the adsorbent on the surface of the adsorbent. The adsorption process using activated charcoal adsorbent is one of the most frequently used non-polar adsorbents because it has better adsorption power and surface area than other types of adsorbents. This study aims to determine the influencing variables and the optimum condition of the natural adsorbent from the activated charcoal of the outer shell of ketapang seeds on decreasing levels of metal Pb (NO3)2. The research method used is an experimental method with a two-level factorial design. The results showed that the adsorption temperature was the most influential variable in this study with an optimum yield presentation of 66.77%. The activated charcoal produced has a water content of 8%, ash content of 5.2% and an absorption capacity of methylene blue of 698 mg/g.

Design and synthesis of LDH nano composite functionalized with trimesic acid and its environmental application in adsorbing organic dyes indigo carmine and methylene blue

This work designed and prepared an organic-inorganic nanocomposite using layered double hydroxide (LDH) inorganic substrate and trimesic acid (TMA) as chelating agent. Subsequently, the synthesized organic-inorganic nanocomposite was assessed using multiple identification methods, including FTIR, EDX, XRD, TGA, and FESEM, and the outcomes demonstrated that the intended structure was successfully prepared. Also, in order to investigate the efficiency of the Mg–Al LDH-TMA nanocomposite as an efficient nano adsorbent, it was used for removal of indigo carmine (IC) and methylene blue (MB) from aqueous solutions. This synthetic nanocomposite showed a high adsorption capacity. The efficiency of the produced nanocomposite in the adsorption of selected dyes was investigated with the help of batch adsorption studies performed in a variety of experimental settings, including dye concentration, adsorbent dose, pH, adsorption temperature and contact time. Furthermore, the produced Mg–Al LDH-TMA nanocomposite exhibits strong stability and can be recycled and reused five times in a row, which is well consistent with the principles of green chemistry.

Selective separation of rhenium from oxygen-pressure leach solution of molybdenite concentrate using modified D201 resin: Experiments and theoretical calculations

Recovering rhenium from highly acidic rhenium-containing leach solutions is challenging for most resins, particularly in multiplexed systems. Herein, we introduce a scheme for selectively obtaining rhenium from a multielement solution containing high concentrations of sulfuric acid using modified D201 resin. Considering the dosage of resin and parameters such as pH and adsorption temperature, the adsorption efficiencies under optimal conditions for rhenium, molybdenum, iron, and cerium were 97.46 %, 0.38 %, 0.94 %, and 1.10 %, respectively. The selective recovery mechanism of rhenium was investigated by fitting the experimental data to kinetic and adsorption isotherm models. The pseudo-second-order and Langmuir models better fit results corresponding to the experimental data, which indicates monolayer chemisorption of ReO4− formed on the resin surface. Meanwhile, various characterizations such as SEM-EDS, FTIR, XPS, etc., indicate that ReO4− initially combines with the protonated −CHN+H2CH2Cl on the modified resin surface and then undergoes ion exchange reaction with doped Cl−. Furthermore, because of the diverse forms and similar properties of molybdenum and rhenium ions in acidic solutions, a theoretical model based on density functional theory was used to simulate the selective adsorption process in leach solution with a pH of 1.7. The simulation results demonstrate a highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap, observed in the following order: ΔEMoO22+ = ΔEReO4− < ΔEMoO42− < ΔEMo7O246−, which implies that MoO22+ and ReO4− were most likely to transition from their ground states to excited states and react with the electron donor and acceptor groups, respectively. Compared with MoO42−, ReO4− is more likely to react with the electron acceptor group and provides the corresponding methods and a theoretical reference for selective separation of rhenium in multielement solutions.

Novel amino-ethyl carboxymethyl cellulose crosslinked ampholyte hydrogel development for Methyl orange removal from waste water

In the modern era, with the rapid growth of various industries, the issues of energy crisis and environmental pollution have garnered increasing attention. One significant source of industrial pollution is printing and dyeing wastewater. This wastewater often contains dyes that have aromatic structures and azo groups, such as Methyl orange (MO), which are both toxic and difficult to degrade. If these dyes are released into the wastewater stream without any treatment, they can have adverse effects on ecological balance and human health. Therefore, it is crucial to identify suitable treatment strategies to efficiently remove dyes from wastewater systems before discharge. In this study, the Methyl orange (MO) azo dye has been removed from dyes-contaminated wastewater, for the first time, using a novel amino-ethyl carboxymethyl cellulose crosslinked ampholyte hydrogel (AECMC). Different characterization methods, including FTIR, TGA, and DSC were used to characterize the generated AECMC compounds. The water absorption and cationic exchange capacities were assessed. Factors affecting the MO anions adsorption including MO concentration, adsorption pH, temperature, time, adsorbent dose, and agitation speed have been investigated. Moreover, the kinetics of the adsorption process was assessed by the use of three models: pseudo-first-order, Pseudo-second-order, and Elovich. Moreover, the mechanism of the adsorption process was monitored using the Intraparticle diffusion and Boyd models. Additionally, the adsorption isotherm was examined using established models such as Langmuir, Freundlich, and Temkin isotherms. The thermodynamic characteristics of the MO adsorption process have been investigated at various adsorption temperatures using the Van't Hoff model. The results obtained from the study indicate that the process of MO adsorption adhered to the Pseudo-second-order kinetic model, the Langmuir isotherm model was found to be applicable, and spontaneous and exhibited an endothermic character. In conclusion, the developed novel amino-ethyl carboxymethyl cellulose crosslinked ampholyte hydrogels (AECMC) have successive in the removal of the MO anionic dye from contaminated wastewater.

Research on Oil and Gas Adsorption Optimization Based on CFD Modeling and Process Simulation.

In the process of oil extraction and refining, some of the liquid light hydrocarbon components will inevitably evaporate into the atmosphere, causing serious air pollution and safety hazards. This paper is focused on oil and gas adsorption systems to comprehensively optimize key parameters by combining computational fluid dynamics (CFD) modeling with process simulation, enabling the efficient treatment of hazardous materials. First, a CFD model of the hydrocarbon adsorption process is established to the porous media model by a user-defined function (UDF). Subsequently, the mass transfer process of oil and gas in porous media is successfully simulated to obtain the gas distribution in an industrial fixed bed adsorption tower. The adsorption tank is intensified, and the gas distribution in the tank is improved by optimizing the height-to-diameter ratio of the equipment and the design of the intake distributor. Third, the cyclic two-tank adsorption model of the pressure swing adsorption (PSA) process is established for key parameters optimization. Finally, the operating parameters and conditions of the PSA process are suspected by considering five factors affecting the adsorption efficiency: adsorption time, adsorption pressure, adsorption temperature, feed flow rate, and purge ratio of the washing step.

Исследование адсорбционного разделения газовых смесей в условиях нестационарности

The influence of the initial concentration, rate and temperature of adsorption on the adsorption separation of gas mixtures (CO2, CH4, N2, H2S) is investigated. Components: N2 – 5%, H2S – 5%, CO2 – 5% and CH4 – 85%. And as an adsorbent granule of clinoptilolite of irregular shape were used. Isothermal adsorption of CO2 was obtained at different temperatures (293, 313, and 323 K). The obtained isotherms of CO2 adsorption showed that with an increase in temperature, the adsorption of CO2 decreased. The type of isotherms corresponds to Langmuir. The output curves of gas mixture adsorption depending on the gas flow rate and various main components of CO2 were also experimentally studied. The output curves of the adsorption of the CO2 component were studied at various gas flow rates of 20, 50, and 80 mL/min. Equilibrium time increases with a decrease in the gas flow rate. Output curves were also obtained depending on the initial CO2 concentrations of 5%, 10% and 20%. It was determined that with a decrease in the initial concentration of CO2, the equilibrium time also increases. Gas mixture components sorbed downwards: H2S→CO2→CH4→N2. The resulting system of model equations describing the adsorption separation of gas mixtures in a fixed adsorbent layer represents a complete mathematical model of the process under unsteady conditions. The obtained regularities of the process of adsorption of gas mixtures testify to the fact that the process takes place under non-stationary conditions. The proposed models for the optimal design of industrial absorbers can be used for adsorption separation of gas mixtures in the conditions of their unsteady flow.

Adsorption efficiency and in-situ catalytic thermal degradation behaviour of microplastics from water over Fe-modified lignin-based magnetic biochar

The efficient removal and degradation of microplastics are critical for protecting aquatic ecosystems. Herein, Fe-modified magnetic biochar (MBC) was synthesized as an adsorbent for removing microplastics in water. The effects of lignin/Fe salt mass ratios, adsorbent amount, adsorption time, adsorption temperature, solution pH, and presence of coexisting anions on adsorption efficiency were investigated. The thermal degradation behaviour and recycling characteristic of microplastics was also explored. Results showed that MBC has a developed pore structure, superparamagnetic property, and abundant oxygen-containing functional groups. The removal efficiency of polystyrene microplastics using MBC-11 was 99 %, with an adsorption capacity of 68.57 mg/g, which was 25 times higher than that of unmodified lignin biochar. The kinetics of the adsorption process followed the pseudo-first kinetic model, and the equilibrium data best fitted the Freundlich model. Thermodynamic results confirmed that adsorption over MBC was a spontaneous, heat-absorbing, and entropy-increasing process. The adsorption mechanism of PS by biochar was mainly via electrostatic and hydrophobic interactions and pore throttle. The thermal-degradation products of PS were mainly hydrocarbons, including styrene, benzene, and toluene, owing to the enhanced β-scission, H-shift, and methylation reactions at MBC catalytic sites. This study provides a scientific basis for the development of control technologies for microplastics removal in water.

Elemental mercury removal by copper-containing brominated pyrolytic chars derived from waste printed circuit boards

Waste printed circuit boards (WPCBs) containing brominated flame retardants (BFRs) would result in serious environmental pollution without pertinent treatments. However, bromine-containing materials have been proven highly efficient for elemental mercury removal (Hg0). This work proposes a win–win strategy of a cost-effective Hg0 removal method and a highly efficient utilization of WPCB-derived chars. Diverse copper-containing brominated pyrolytic chars of WPCBs were prepared in a fixed bed reactor at 500–700 °C tailored for Hg0 removal from coal-fired flue gas. The resulting copper-containing pyrolytic chars were proven to have a high Hg0 removal efficiency. Various characterizations and adsorption curves insights into the impacts of copper, sorbent weights, pyrolysis and adsorption temperatures, on Hg0 removal efficiency of WPCB-derived chars. The results indicate that copper in WPCBs enhances the fixation of the bromine elements in pyrolytic chars, resulting in improved Hg0 removal performance. The optimal pyrolysis and adsorption temperatures for pyrolytic chars are 600 °C and 140 °C, respectively. Under optimized conditions, a Hg0 removal efficiency exceeding 90 % is realized after 30 min of adsorption. Notably, the results indicating the Hg0 adsorption capacity of WPCB-derived chars rivals that of commercial activated carbons and significantly surpasses that of biochar. Both adsorption kinetics and characterizations affirm that chemisorption is the predominant adsorption method. The C-Br bond and CuO emerge as crucial active sites facilitating the oxidation of Hg0.

Study on the synthesis of ordered mesoporous alumina with high specific surface area using inorganic aluminum sources and its adsorption performance for carbon dioxide

In this work, inexpensive aluminum nitrate was used as the raw material and ammonium carbonate as the precipitant. Ordered mesoporous alumina (OMA) with a high surface area was synthesized using suitable template agents and auxiliary agents. The synthesized materials underwent characterization via X-ray powder diffraction (XRD), N2 adsorption-desorption (BET), transmission electron microscopy (TEM), and other analytical techniques. The effects of various template agents, aging durations, calcination methods, and calcination temperatures on the structure of the synthesized OMA were investigated. Key factors influencing the formation of inorganic precursors, the self-assembly of template agents with inorganic precursors, and the pore formation process (involving template agent and water removal) during synthesis were analyzed. Using the synthesized OMA as the substrate and triethylenetetramine (TETA) as the modifier, the impact of modified materials on CO2 adsorption performance was assessed. The results showed that OMA prepared with P123 as the template agent and ammonium dihydrogen phosphate as the auxiliary agent exhibited a specific surface area of 545.2 m2/g, an average pore diameter of 3.8 nm, and a pore volume of 1.01 cm3/g. The addition of auxiliary agents significantly increased the specific surface area of the synthesized material. The modified TETA-OMA, with a loading capacity of 50 %, achieved an adsorption capacity of 216.25 mg/g at an intake flow rate of 20 mL/min and an adsorption temperature of 40 °C. After six cycles of adsorption-desorption recycling, minimal changes were observed in the adsorption performance, indicating excellent regeneration capability. The synthesized high-surface-area ordered mesoporous alumina holds potential for industrial applications.

Molecular simulation of different VOCs adsorption on nitrogen-doped biochar

Nitrogen-doped biochar has potential application in the removal of volatile organic compounds (VOCs) from coal-fired flue gas. To explore the adsorption characteristics of different VOCs on nitrogen-doped biochar by molecular simulation, in this study, six typical aromatic VOCs (benzene, toluene, phenol, naphthalene, p-xylene, and chlorobenzene), and an amorphous carbon model with nitrogen/oxygen groups were selected and constructed. Grand Canonical Monte Carlo (GCMC) simulations were performed to evaluate the adsorption capacities of VOCs on nitrogen-doped biochar. The results showed that the optimized carbon model was in good agreement with the pore structure parameters of nitrogen-doped biochar, and the agreement of toluene adsorption capacities was more than 80 % at room temperature. The adsorption capacity of nitrogen-doped biochar for different VOCs was 184 − 317 mg/g with the order of phenol > naphthalene > p-xylene > toluene ≈ benzene ≈ chlorobenzene (single-component adsorption). Among them, the phenol molecule is more easily adsorbed due to its strong polarity, resulting in stronger electrostatic interaction with the adsorbent. The decrease rate of benzene adsorption capacity is the lowest with increasing adsorption temperature because of its low molecular weight. As gas concentration increases, van der Waals interactions between molecules and between molecules and porous carbon also increase, leading to an increase in VOCs adsorption capacity. Nitrogen-doped biochar not only has the highest VOCs/N2 selective adsorption coefficient for phenol (up to 36) but also has the highest adsorption capacity of 63 mg/g when 6 kinds of VOCs are multi-component adsorption at 25 °C. This study can provide references for the practical application of adsorption method in the removal of VOCs from coal-fired flue gas.

Pengaruh Temperature dan Waktu Absorpsi Terhadap Properti Fisik dan Kimia dari Minyak Goreng Bekas yang Dimurnikan Menggunakan Adsorben Bentonit dan Karbon Ampas Tebu.

Bentonite and carbon bagasse adsorbents are used to study the effects of temperature and absorption time on the physico-chemical properties of refined used cooking oil. Any extended use of outdated cooking oil will have an impact on the body's health since it causes fat cells to accumulate in various vital organs. Used cooking oil can be cleaned by using adsorbents like bentonite, bagasse, and activated carbon. This study investigated the effects of temperature and adsorption period on the purification results of used cooking oil using activated carbon adsorbents comprised of bagasse and bentonite. In this study, a factorial group randomised design was used. First, there is a 1:1 adsorbent to substrate ratio. Secondly, there are four adsorption temperature levels: 30°C, 60°C, 90°C, and 120°C. The third factor is adsorption time, which are: 30, 60, 90, and 120 minutes. Counting the quantity of acids, peroxides, and free fatty acids was one method of data analysis. The best results are obtained when used cooking oil is refined using activated carbon, bagasse, and bentonite at 120°C for 90 minutes of adsorption. The result is an acid number of 0.913, a peroxide number of 2.532, and a free fatty acid content of 0.459%.

Adsorption of Cr(VI) from aqueous solutions using inorganic clays modified magnetic chitosan adsorbent: Kinetic and thermodynamic study

Inorganic clays modified magnetic chitosan adsorbent (ICMMCA) was successfully prepared and systematically characterized in chemical structure and morphology. Effect of variables including initial pH and concentration of Cr(VI) in the solution, adsorption time, adsorption temperature and coexisting ions on the performance of ICMMCA in Cr(VI) removal from water were evaluated. Furthermore, the kinetic and thermodynamic studies were conducted to elucidate the adsorption mechanisms and thermodynamic characteristics of the adsorption process. The results demonstrated that the maximum Cr(VI) adsorption capacity of 94.67 mg/g could be achieved when the adsorbent loading was 1 g/L, the initial concentration of Cr(VI) was 100 mg/L, the adsorption time was 60 min and solution pH was at 5. The adsorption data could be well fitted by the Freundlich isotherm model. The thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. The adsorption process could be described by the pseudo-second-order kinetic model.

The hyper-crosslinked aniline polymer@MOFs hybrid materials reinforced with active ionic sites for efficient and fast Cr(VI) removal

The adsorption of toxic metal ions by composite materials of metal–organic frameworks (MOFs) has attracted significant attention in recent years. In this work, a series of hybrid materials HPAN@M−x consisting of protonated hyper-crosslinked aniline polymer (HPAN) and MOFs were synthesized via the Friedel-Crafts reaction between aniline and dimethoxymethane in the presence of MIL-101(Cr), followed by protonation with hydrogen bromide. These hybrid materials exhibited enhanced adsorption rate and capacity for Cr(VI) ions compared to both individual MIL-101(Cr) and HPAN. The effects of the ratio of aniline to MIL-101(Cr), solution pH, adsorption temperature, impurity ions on the removal of Cr(VI) ions were systematically investigated. Notably, HPAN@M−b not only achieved an adsorption capacity up to 290.9 mg·g−1 in 7 min but also exhibited excellent cycling stability by maintaining a high Cr(VI) removal efficiency of 95.6 % after five cycles. The enhanced adsorption performance is attributed to the synergistic effect between MIL-101(Cr) and HPAN. Mechanism studies indicated that the removal for Cr(VI) ions involved a combination of ion exchange and electrostatic adsorption processes. Additionally, the desorbed Cr(VI) ions were transformed into added-value barium chromate (BaCrO4) precipitates, allowing for resource utilization of Cr(VI) ions. This study represents a significant advancement towards developing MOFs-based hybrid materials for practical treatment of chromium-containing wastewater.

The use of chitosan aerogels as an adsorbent for the regeneration of frying oil

One of the most commonly used food preparation methods is deep-fat frying. The improvement of the quality of used frying oil (UFO) is important because the reuse of frying oil could provide significant savings to the food industry. This study aimed to enhance the quality of used sunflower oil by using chitosan aerogels (CA), which can be considered as novel adsorbents with an increased surface area compared to chitosan powder. Aerogels are novel nanostructured materials with high porosity and large surface area. In this study, CA were produced by drying the 2% (w/v) chitosan gels using supercritical drying. In the study, 32 consecutive deep-fat frying were performed using potato slices in sunflower oil at 180 ± 5 °C. The effect of the adsorbent concentration (0.5, 1, and 2% (w/w)) and different adsorption temperatures (90, 135, and 180 °C) were studied by examining the UFO before and after the adsorption treatments. The physicochemical properties of the oil were analyzed by determining free fatty acid (FFA) content, total polar compounds (TPC), smoke point, p-anisidine value (p-AnV), and color (CIE L*, a*, b*). Moreover, the structural changes of aerogels after the adsorption process were investigated by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). CA could reduce the % FFA values from 0.44% to 0.18% due to the ionic interaction between CA and FFA. In addition, TPC value and the smoke point increased after the treatments. The p-AnV was compensated with CA, indicating that secondary oxidation products were adsorbed. Moreover, CA caused a darker color after the adsorption treatments. Additionally, compared with magnesium silicate, the same concentrations of CA were found more effective in improving all the quality parameters of oil except for the L* values.

Porous sodium alginate/poly (acrylic acid) composites cross-linked with FeCl3 for acid black 1 dye removal from aqueous solution

This study developed a polymeric composite, sodium alginate (SA)/poly (acrylic acid) (PAA) cross-linked with FeCl3 (SA/PAA-Fe), for its function as adsorbent to eliminate acid black 1 dye (AB1) from an aqueous solution. The structural analysis of SA/PAA-Fe revealed a porous structure. To comprehensively evaluate the adsorption of AB1 onto SA/PAA-Fe and gain insight into its mechanism, we examined the effects of solution’s pH, initial dye concentration, adsorbent dosage, contact time, and adsorption temperature. The best adsorption conditions for achieving a highly effective removal percentage of 95.43 % were a pH of 8.9, contact period of 90 min, and a temperature of 45 °C. Pseudo-second-order and Langmuir models were fitted for the isotherm and kinetic model parameters, respectively. Thermodynamic analyses strongly suggested that the adsorption process occurred was endothermic and spontaneous. The adsorption of AB1 was primarily observed on the solid surface, as confirmed by the SEM-EDS and FTIR measurements.

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.

A study on the performance of a recyclable adsorbent La@Fe for phosphate adsorption in wastewater

Phosphorus(P) is the key element of the growth of phytoplankton, and is also significant cause of water eutrophication. In this work, the magnetic Fe3O4 (FE) microspheres were employed as the core material, the La compound was coated on the surface of the FE microspheres and the adsorbent obtained was denoted as La@Fe. The effects of preparation conditions including the dosage of NaOH, the preparation time, the ratio of FE and LaCl3 (LC), and the stirring time were discussed. The optimized La@Fe has a good adsorption capacity (130–160 mg·g−1) and strong magnetic recovery capacity (43.4 emu/g). In the low concentration (1 mg·L−1), the optimized La@Fe still had an excellent performance. It can keep a good adsorption in a wide pH range (3−8). Except Na2CO3, common anions (NaHCO3, NaCl, NaNO3, Na2SO4, KF, KNO2) in the wastewater could not affect the adsorption capacity of La@Fe. After 7 regeneration, the adsorption capacity of La@Fe reduced by 25% indicating the excellent regeneration property of La@Fe. The La@Fe was analyzed by SEM, TEM, XRD, XPS, BET, and LPS, and the obtained results showed that the particles of La@Fe were spherical, the particle sizes were between 0.1 and 100μm. The main components at the surface of La@Fe was La-(OH), which adsorbed phosphate to form La-PO4. The specific surface area of La@Fe was small and the mesopores were main pore structure. In addition, the adsorption kinetics analysis indicated that the Elovich model worked well on modeling La@Fe adsorbing phosphate, so the adsorption was chemical adsorption with heterogeneous adsorbing surfaces. Adsorption isotherms experiments revealed that the increasing adsorption temperature would enhance the adsorption capacity of La@Fe. It could be obtained from the thermodynamic experiments that the adsorption process was endothermic and chemical adsorption. Therefore, La@Fe is an excellent phosphate adsorbent and has a good application prospect in the field of phosphorus recovery and adsorbent reuse.

Coupled variation of pressure and temperature for methane adsorption in coal seam under three initial pressures

Coupled variation of pressure and temperature for methane adsorption in coal seam under three initial pressures

Pyrolysis solid product as a sorbent for flue gases mercury capture — Part II: Sorbent utilization

This study explores using solid pyrolysis products from six materials as sorbents to capture mercury from flue gas in an experimental fluidized bed combustor. It investigates the effects of activation methods, adsorption temperature, and Hg0/Hg2+ ratios on mercury removal efficiency. Physical and chemical activations are conducted using steam and NaOH, respectively. Tests are run at 100–160 °C with 5 g of sorbent. Results show 120 °C as optimal, with sorbents losing 0.34 % and 0.39 % efficiency with increasing temperature for lignite and black coal. Specific surface area (up to 641 m2∙g–1) significantly influences cumulative removal efficiency (CRE), reaching 80.8 % for lignite and 73.85 % for black coal. Mercury gas recovery averages 35.5 % and 53.7 % after physical and chemical activations. Lignite sorbents exhibit higher CRE than black coal, indicating greater mercury oxidation in black coal flue gas. This study offers a promising method for char recovery from pyrolysis, suggesting competitive sorbents for industrial use.

The Effectiveness of Carbonized Neem Leaves Adsorbent for the Removal of Phenol from Synthesized Effluent Using the Batch Process Method

The adsorption of phenol in aqueous solution was investigated using carbonized neem leaves adsorbents. The effect of various factors such as contact time, phenol concentration, pH, temperature, and amount of adsorbent on the adsorption capacity of the adsorbents was determined. The results show that maximum adsorption was obtained at a contact time of 150 minutes, at a phenol concentration of 50 mg/L, optimum adsorption temperature of 45⁰C, pH of 2 and adsorbent dosage of 3 g/L. The equilibrium data was well described by the Freundlich isotherm equation (R2= 0.955 ). This shows a heterogenous adsorption process. The kinetics of the process were explained by the intra-particle diffusion models (R2&gt;0.9). This fitted data indicates a degree of boundary layer control and is not limited to intra-particle diffusion.