Records with Keyword: Adsorption
Showing records 1 to 25 of 214. [First] Page: 1 2 3 4 5 Last
Adsorption of Multi-Collector on Long-Flame Coal Surface via Density Functional Theory Calculation and Molecular Dynamics Simulation
Gan Cheng, Yujie Peng, Yang Lu, Mengni Zhang
February 10, 2024 (v1)
Keywords: Adsorption, collector, long-flame coal, molecular dynamics, quantum chemistry
The quantum chemical properties of long-flame coal (LFC) and collectors (kerosene, diesel, diethyl phthalate (DEP), biodiesel collector (BDC), and emulsified biodiesel collector (EBDC)) were analyzed via the density functional theory (DFT). The molecular dynamics (MD) of the coal−collector−water system and the adsorption of collectors on LFC were conducted based on the first principles. The results showed that the frontier molecular orbitals of kerosene, diesel, DEP, and BDC were 0.38 eV, 0.28 eV, 0.27 eV, and 0.20 eV, respectively. The chemical reactivity order of the above mentioned collectors was BDC > DEP > diesel > kerosene. Kerosene, diesel, and DEP adsorbed with carbonyl, hydroxyl, and carboxyl groups in LFC, respectively. Carboxyl groups in BDC and carboxyl groups in LFC bilaterally adsorbed, while BDC repelled water molecules via hydrogen bonds on the LFC surface. In the systems of BDC and EBDC, the diffusion coefficients of a water molecule were 2.83 × 10−4 cm2/s and 3.73 × 1... [more]
Acetylcellulose Recovery from Waste Residual for Attenuating Reactive Dye from Aquaculture Waste as a Fascinating Synergistic Ecology Effect
Hossam A. Nabwey, Maha A. Tony, Manasik M. Nour
February 10, 2024 (v1)
Subject: Environment
Keywords: acetylcellulose waste, Adsorption, isotherm models, levafix dye, wastewater treatment
Waste valorization is attracting not only the scientific world but also the world. Acetylcellulose wastes from cigarette filter residuals are signified as the largest global impact of solid waste. Acetylcellulose recycling for desired products is a promising way for environmental management. In this regard, the current investigation is dealing with the immersion of residual filters sequentially into aqueous solutions of alkali and ethanol before water washing, which converts them into a superhydrophobic acetylcellulose adsorbent material. The morphology and characteristics of the acetylcellulose fiber were characterized using a Scanning Electron Microscope (SEM) and Fourier-Transform infrared spectroscopy (FTIR). The adsorption tendency was checked for Levafix Blue dye compromised in an aqueous stream as a model textile polluted effluent. The experimental results exposed that the acetylcellulose fiber displayed a sensible textile dye elimination from the dying stream. Langmuir isotherm... [more]
Study and Characterization of H3PO4 Activated Carbons Prepared from Jujube Stones for the Treatment of Industrial Textile Effluents
Nasma Bouchelkia, Kheira Benazouz, Amal Mameri, Lazhar Belkhiri, Nadia Hamri, Hayet Belkacemi, Abdelhalim Zoukel, Abdeltif Amrane, Fodil Aoulmi, Lotfi Mouni
February 10, 2024 (v1)
Subject: Materials
Keywords: activated carbon, Adsorption, chemical activation, textile effluent, wastewater treatment
Dyes are responsible for major environmental issues globally due to their toxicity, large-scale production, and extensive use in various industrial sectors. Pollution caused by hazardous dyes is mainly due to textile waste, which is constantly discharged into the aquatic system, often causing harm to humans and affecting water quality. In recent years, the removal of dyes from industrial textile wastewater has been a major challenge. Numerous technologies and methods have been developed to remove dyes from wastewater and meet clean water requirements. In this study, the effectiveness of activated carbon prepared by chemical activation of jujube stones for textile wastewater treatment was investigated. The effects of the concentration of H3PO4 and the carbonization temperature on the activated carbon’s properties were studied. Several physicochemical methods, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction, methylene blue i... [more]
Fe3O4@Granite: A Novel Magnetic Adsorbent for Dye Adsorption
Gamze Topal Canbaz
January 12, 2024 (v1)
Subject: Materials
Keywords: Adsorption, chemical co-precipitation, Fe3O4, magnetic granite, Reactive Black 5
Magnetic granite (MG), a new and low-cost adsorbent, was prepared by the chemical co-precipitation of Fe2+ and Fe3+ using granite (G), which is a magmatic rock type. The adsorption of the Reactive Black 5 (RB5) dye from aqueous solutions on Fe3O4-modified granite was examined in a batch system. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray fluorescence spectrometry (XRF), X-ray diffractometry (XRD), N2 adsorption−desorption, vibrating-sample magnetometry (VSM), and point-of-zero charge (pHpzc) analysis were used to characterize the prepared MG. Magnetic granite displayed significant magnetization and could be easily separated using external magnets. The maximum adsorption capacity was 29.85 mg/g at 298 K. According to kinetic and isothermal examinations, the pseudo-second-order model and Langmuir isothermal adsorption were the best fit for adsorption. It was found that the enthalpy change ΔH (kJ/mol) was −31.76,... [more]
Investigation of the Adsorption Process of Triclosan from an Aqueous Solution, Using Nanoporous Carbon Adsorbents, Obtained after Treatment of Organic Household and Vegetable Waste
Ivanka Stoycheva, Bilyana Petrova, Boyko Tsyntsarski, Pavlina Dolashka, Angelina Kosateva, Nartzislav Petrov
January 12, 2024 (v1)
Subject: Environment
Keywords: Adsorption, environmental protection, nanoporous carbon adsorbents, organic waste, triclosan
The absorption of triclosan on the surface of four different carbon adsorbents, obtained on the base of plant and household waste (RDF), provided by Sofia Waste Plant, was investigated. The obtained results indicate that the most important parameters, which determine the process of triclosan adsorption by adsorbent surface are pore texture, the size of the accessible surface for the molecules of triclosan, and the chemical nature of the adsorbent surface. It was found that the obtained adsorbents can be successfully applied for the extraction of triclosan from waste and drinking water. The possibilities for solid products, obtained by thermal treatment of household and vegetable waste, to be applied successfully in a water purification technique are discussed.
The Impact of Solar Radiation at Different Colombian Thermal Floors on an Adsorption Refrigeration Cycle
Dario Serrano-Florez, Aduar J. Camargo, Gail Gutierrez, Marlon Bastidas-Barranco, Edwin Chica, Andres Colorado
January 5, 2024 (v1)
Keywords: activated carbon-methanol, Adsorption, cooling, solar energy, solar radiation, thermal floors
The process of energy transition in Colombia has sparked an exploration into appropriate geographical areas for the utilization of solar energy. The country’s rugged terrain and significant climate variability pose challenges for implementing standardized technologies uniformly across all regions. Consequently, this study aims to develop and apply a mathematical model to characterize the performance of a solar adsorption cooling system under the environmental conditions found in six distinct Colombian cities, taking into account different thermal profiles and extreme weather periods such as the El Niño and La Niña phenomena. The selected mathematical model was simulated in these cities, considering ambient temperature and solar radiation variables over a twelve-month period during these extreme weather phenomena and an additional twelve-month period representative of a typical year with minimal influence from these phenomena. The results indicated that despite a lower coefficient of pe... [more]
Experimental Studies of Methane Adsorption on Activated Carbon and 3D Graphene Materials
Ziwen Zhu, Muyuan Zhang
January 5, 2024 (v1)
Subject: Materials
Keywords: 3D graphene materials, activated carbon, Adsorption, carbon-based materials, methane storage
Two kinds of slit pore carbon materials, namely activated carbon (AC) and 3D graphene materials (3D-GS), were purchased to examine their methane storage capabilities. The structural analysis and characterization of AC and 3D-GS were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), the X-ray energy dispersive spectrum (EDS), and N2 adsorption/desorption isotherms. Additionally, a thermodynamic framework was employed in the Henry’s law region to evaluate the potential well between the adsorbed fluid and adsorbent. The adsorption behavior of methane on two materials at room temperature and high pressure was also investigated. The results show that the Toth equation is the most suitable model for predicting adsorption isotherms than the Langmuir and L-F equations and determines that the absolute uptake of methane storage on AC and 3D-GS are, respectively, 7.86 mmol·g−1 and 8.9 mmol·g−1 at 298 K and 35 bar. In the Henry’s law region, the isosteric heat of metha... [more]
Separation of VOC Gaseous Mixtures Using an Adsorption−Desorption Device
Ľudmila Gabrišová, Oliver Macho, Martin Juriga, Zuzana Gábrišová, Ivan Valent, Juraj Kabát, Jaroslav Blaško, Róbert Kubinec
November 30, 2023 (v1)
Keywords: Adsorption, desorption, Ethanol, granulated activated carbon, stripping
The aim of this work was to separate ethanol in an experimental adsorption−desorption device. We focused on concentrating ethanol by adsorption onto granulated activated carbon in its gaseous phase, which was produced by stripping a matrix with different ethanol concentrations (2, 5, 10, and 15% v/v). For adsorption, three kinds of granulated activated carbon (GAC) were used, marked as GAC1, GAC2, and GAC3. The separation product had a higher ethanol concentration than the initial ethanol concentration before the adsorption−desorption process. The enrichment factor was, in the case of the initial ethanol concentration, 2% v/v at the level of 10. With our new adsorption−desorption device, it is possible to achieve a product with an ethanol concentration of 59.0% v/v with stripping, adsorption, desorption, and condensation. To verify the separation efficiency, a real matrix (fermentation broth) was used. The ethanol concentration in the real matrix was, at the beginning of the separation... [more]
Removal of Fluoroquinolone Antibiotics by Chitosan−Magnetite from Aqueous: Single and Binary Adsorption
Quy M. Bui, Tung Q. Vu, Xuan T. Vuong, Vinh D. Nguyen, Linh T. N. Nguyen, Ha T. Le, Hoa T. H. Nguyen, Van Phuoc Nguyen
September 21, 2023 (v1)
Subject: Biosystems
Keywords: Adsorption, binary, chitosan, ciprofloxacin, levofloxacin, magnetite
In this research, chitosan−magnetite composites (CS-MNPs) were successfully synthesized using a rapid and easy technique. The materials were characterized by FTIR, XRD, EDX, TEM, VSM, and BET methods. The removal of the antibiotics ciprofloxacin (CFX) and levofloxacin (LFX) from aqueous solutions by CS-MNPs adsorbent was investigated. The influencing factors in a single adsorption system were studied, including pH (1−11), initial concentration (2.5−15.0 mg/L), contact time (0−120 min), and adsorbent dosage (5−50 mg/L). The experiment data were analyzed by pseudo-first-order and pseudo-second-order kinetic models. The adsorption isotherms were studied by fitting the experimental data to the Langmuir, Freundlich, and Temkin models. The results indicated that the adsorption of CFX and LFX antibiotics was consistent with the pseudo-second-order kinetics model, the Langmuir isotherm model. Binary adsorption systems (CFX: LFX) with concentration ratios of 1:0, 1:0.5, 1:1.0, 1:1.5, and 1:2.0... [more]
Tailing Ash for the Removal of Methylene Blue from Aqueous Solutions by Batch Adsorption
Cik Jamla Farhan bt Yahya, Thomas Shean Yaw Choong, Fan Li, Wan Azlina Wan Ab Karim Ghani, Farah Nora Aznieta Abd Aziz, Siti Nurul Ain Md. Jamil
September 20, 2023 (v1)
Subject: Environment
Keywords: Adsorption, dye, tailing ash
One of the more problematic textile wastewaters to manage is dyeing wastewater, especially methylene-blue-containing wastewater. Its release has a significant negative impact on ecosystems, which could harm the environment. Adsorption techniques are still an efficient technology to eliminate and remove the coloring agent. Tailing ash, obtained from the floatation process, was selected as an adsorbent in the present study. The purpose of this study was to analyze the performance of tailing ash (TA) for MB removal. The effects of operating parameters investigated were pH (2−10), stirring speed (50−150 rpm), initial dye concentration (20−100 mg/L), contact time (120 min), adsorbent dosage (0.5−2.5 g), and temperature (25−45 °C). The performance of TA pretreated with hydrogen peroxide (H2O2) and thermal tailing ash were also investigated. The experimental results for batch adsorption indicated that 96.23% removal of methylene blue took place at the optimum condition (pH = 10, initial adsor... [more]
A Review of Treatment Technologies for Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) in Water
Juntao Cheng, Liming Huang, Yunfeng Li, Zhen Zhang, Runzhi Mu, Changqing Liu, Shuncheng Hu, Yihua Xiao, Mengchen Xu
September 20, 2023 (v1)
Subject: Biosystems
Keywords: Adsorption, advanced oxidation processes, membrane separation, microbial treatment, PFOA, PFOS
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are a category of persistent, non-degradable pollutants that are widespread in the environment and in humans. They have attracted considerable attention due to their high bioaccumulation, multiple toxicities, long-term stability, and, in particular, their effects on human health. Therefore, there is an urgent need for highly efficient technologies and systematic mechanisms for the degradation of PFOS and PFOA. Therefore, we summarize four mainstream technologies for the degradation of PFOS and PFOA in water and their research progress in this review, namely adsorption, advanced oxidation processes, microbial treatment, and membrane separation. Among them, adsorption technology is the earliest and relatively mature, the advanced oxidation process has relatively high treatment efficiency, there are deep and broad development prospects for microbial treatment in the future, and membrane separation technology can recycle ra... [more]
Dyes and Heavy Metals Removal from Aqueous Solutions Using Raw and Modified Diatomite
Simona Gabriela Muntean, Maria Andreea Nistor, Raisa Nastas, Oleg Petuhov
September 20, 2023 (v1)
Subject: Environment
Keywords: Adsorption, equilibrium, kinetic, pollutant, Wastewater
The progress of the textile industry has led to a severe increase in the discharge of colored effluents, polluted with dyes and metal ions (non-biodegradable, carcinogenic to humans and environmental hazards). The implementation of effective methodologies and materials for the treatment of wastewater has become an urgent requirement. The present work describes the application of two samples of mineral materials—Ghidirim diatomite and modified diatomite—as adsorbents for the removal of dyes—Acid Blue 350, Methylene Blue, Basic Red 2—and of metal ions—copper, zinc, and lead—from aqueous solutions. In order to determine the optimal working conditions by which to ensure maximum removal efficiency, the influence of the nature and amount of the sorbent, the initial concentration of pollutant, and the temperature were studied. Working under normal conditions (room temperature, solution pH) efficiencies greater than 80% were obtained for the removal of dyes and metal ions. The adsorption fitte... [more]
Fabricating Porous Carbon Materials by One-Step Hydrothermal Carbonization of Glucose
Ziyun Yao, Wenqi Zhang, Xinying Yu
August 2, 2023 (v1)
Subject: Materials
Keywords: Adsorption, glucose, hydrothermal carbonization, porous carbon materials, sulfuric acid
The present study concerned the production of glucose-based porous carbon materials by a one-step acid-catalyzed HTC. The samples were characterized by elemental analysis (EA), scanning electron microscope (SEM), Brunauer−Emmett−Teller (BET), Fourier transform infrared (FTIR) and point of zero charge (pzc). Experimental results showed that the addition of sulfuric acid (SA) with different dosages in the HTC system could improve the yield of products and reduce chemical oxygen demand (COD) of the process water. When the glucose and acid was at a mass ratio of 1:4 (glucose: SA = 1:4), the hydrochar obtained (H-G9) had a larger specific surface area (SBET = 296.71 m2/g) and higher abundance of functional groups on the surface than that of other samples, such as sulfur-containing functional groups and carboxylic groups, belonged to the mesoporous material with highly negatively surface charged. H-G9 exhibited the optimum adsorption for methylene blue (MB). H-G9 adsorbed MB with an initial... [more]
Influence of the Adsorption Bed Composition on the Low-Pressure Fluidization
Anna Kulakowska, Anna Zylka, Jaroslaw Krzywanski, Dorian Skrobek, Karolina Grabowska, Marcin Sosnowski, Wojciech Nowak
August 2, 2023 (v1)
Subject: Materials
Keywords: Adsorption, adsorption cooling and desalination systems, carbon nanotubes, Energy Efficiency, fluidization, low pressure, net-zero emission, Renewable and Sustainable Energy, silica gel
The paper presents an innovative concept of the fluidization of an adsorption bed carried out under low-pressure conditions. Additionally, different bed mixes were used to test the effects of the bed composition on fluidization. Fluidization was caused by the pressure difference and the velocity of the flowing water vapor. These features make the research presented in this article significantly different from other studies known in the literature and constitute the main novelty of the paper. Silica gel with a particle diameter of 200−250 µm (Geldart group B) with aluminum and carbon nanotube additives was fluidized under reduced pressure (10−25 mbar). The pressure difference results in the flow of water vapor and, consequently, induces fluidization. The pressure in the evaporator was approx. 10 mbar, while in the reaction chamber it was approx. 25 mbar. The pressure difference of about 10−15 mbar allows for a flow of water vapor between the evaporator and the reaction chamber. During t... [more]
Study on Adsorption and Photocatalytic Properties of Zinc Ferrite
Jinlin Yang, Xingnan Huo, Zongyu Li, Hengjun Li, Teng Wang, Shaojian Ma
July 4, 2023 (v1)
Subject: Materials
Keywords: Adsorption, amido black 10B, methyl orange, methylene blue, photocatalysis, zinc ferrite
In this study, methyl orange, methylene blue, and amido black 10B were removed as target dyes using purified, synthetic, and purchased zinc ferrite as adsorbents and photocatalysts. The highest removal rates of amido black 10B by these adsorbents ranged from 81.62% to 88.33%. The removal rate of methyl orange was approximately 1%, and the removal rate of methylene blue was approximately 2%. Hence, an investigation was conducted to elucidate the factors that influence the removal efficacy of purified zinc ferrite on amido black 10B. Titanium dioxide prepared at different calcination temperatures was unsuccessful in removing amido black 10B, but the physical mixing of titanium dioxide prepared at suitable calcination temperatures with purified zinc ferrite had a positive effect on amido black 10B removal. Since zinc ferrite could not be used as an adsorbent to remove methyl orange and methylene blue, the photocatalytic degradation properties of zinc ferrite and its influencing factors we... [more]
Wet-Process-Modified Blue-Green Algae Biochar by K2FeO4 for the Efficient Adsorption of Cr(VI) from Water
Aihua Cheng, Xingwen Wang, Xiaohe Liu, Chi He
June 7, 2023 (v1)
Subject: Environment
Keywords: Adsorption, blue-green algae, hexavalent chromium, potassium ferrite, wet modification
Iron-modified biochar adsorbent shows its promise for removing Cr(VI) from water. However, the traditional dry-grinding modification methods to prepare iron-modified biochar (DFeBC) usually result in the aggregation of iron oxide particles, thus impeding the adsorption capacity. Herein, blue-green algae waste derived biochar modified in a wet process by K2FeO4 (WFeBC) was developed, and it showed well-distributed iron oxide on the surface of the biochar. As a result, WFeBC displayed a larger theoretical adsorption capacity of 66.22 mg/g than that of DFeBC (48.54 mg/g). It was found that the uniform-distributed iron oxide and abundant oxygen functional groups of WFeBC played an important role in the removal process of Cr(VI). In the adsorption process, the reduction of Cr(VI) to Cr(III) by Fe(II) promoted the removal of hexavalent chromium. The Cr(VI) will be attracted by protonated oxygen functional groups through electrostatic interaction and complexation in an acid environment. All t... [more]
CO2 Adsorption Performance of Activated Coke Prepared from Biomass and Coal
He Gao, Shaohua Wang, Miaomiao Hao, Wei Shao, Shuhui Zhang, Lei Zhang, Xiaohan Ren
May 24, 2023 (v1)
Keywords: activation, active coke, Adsorption, Carbon Dioxide, nitrogen-containing functional groups
CO2 adsorption is one of the promising CCS technologies, and activated coke is a solid adsorbent with excellent adsorption properties. In this study, activated coke was prepared by using bituminous coal and coconut shells activated with KOH or CaCl2 in a physically activated atmosphere and modified with ammonia. The effect of the active agent impregnation ratio on the physicochemical properties of activated coke was investigated by N2 adsorption isotherms, scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The CO2 adsorption performance of activated coke was tested, and the effect of nitrogen-containing functional groups on CO2 adsorption was investigated by experiments and simulations. The results showed that the specific surface area of activated coke reached 629.81 m2/g at a KOH impregnation ratio of 0.5 and 610.66 m2/g at a CaCl2 impregnation ratio of 1. The maximum CO2 adsorption capacity of activated coke reached 71.70 mg/g and 90.99 mg/g for c... [more]
MOF-801/Graphene Adsorbent Material for Greenhouse Climate Control System—Numerical Investigation
Andrew N. Aziz, Raya Al-Dadah, Saad Mahmoud, Mohamed A. Ismail, Mohammed K. Almesfer, Marwa F. El-Kady, Hassan Shokry
May 24, 2023 (v1)
Subject: Materials
Keywords: Adsorption, COMSOL, Matlab, Modelling, MOF-801/Graphene, Simulation
Greenhouses with efficient controlled environment offer a promising solution for food security against the impacts of increasing global temperatures and growing water scarcity. However, current technologies used to achieve this controlled environment consume a significant amount of energy, which impacts on operational costs and CO2 emissions. Using advanced metal organic framework materials (MOFs) with superior water adsorption characteristics, this work investigates the development of a new technology for a greenhouse-controlled environment. The system consists of MOF coated heat exchanger, air to air heat exchanger, and evaporative cooler. A three-dimensional computational fluid dynamics (CFD) model was developed using COMSOL software and experimentally validated for the MOF-801/Graphene coated heat exchanger (DCHE) to determine the best cycle time and power input. It was found that using desorption time of 16 min and power input of 1.26 W, the maximum water removal rate was obtained... [more]
Modified Activated Carbon as an Effective Hydrogen Adsorbent
Paweł Baran, Bronisław Buczek, Katarzyna Zarębska
April 27, 2023 (v1)
Keywords: active carbon, Adsorption, Hydrogen, storage
Hydrogen adsorption measurements were taken by the weighting method using the Sartorius low-pressure microbalance. Experiments were conducted at two temperatures: 77.5 and 300 K; the adsorbent used was active carbon obtained from wood and modified with potassium hydroxide. The porous structure of the carbon prior to and after modification was evaluated based on the nitrogen adsorption and desorption data. Thus, the densimetric characteristic of active carbon was modified; porous structures were developed in the range of micro-, meso- and macropores and the volume of hydrogen adsorbed at 77.5 K showed an almost four-fold increase. Modified active carbons are found to be suitable for applications in hydrogen storage systems.
Oxytetracycline Adsorption from Aqueous Solutions on Commercial and High-Temperature Modified Activated Carbons
Joanna Lach, Agnieszka Ociepa-Kubicka, Maciej Mrowiec
April 27, 2023 (v1)
Subject: Materials
Keywords: activated carbon, Adsorption, oxytetracycline, thermal modification of activated carbon
The aim of the work was to evaluate the possibility of using commercial and modified activated carbons for the removal of oxytetracycline from aqueous solutions. The kinetics and statics of adsorption as well as the effect of the activated carbon dose and solution pH on the efficiency of the oxytetracycline adsorption were analyzed. Based on the study of oxytetracycline adsorption isotherms, the activated carbons were ranked in the following order: F-300 > WG-12 > Picabiol > ROW08 > WACC 8 × 30 > F-100 > WAZ 0.6−2.4. The most effective activated carbons were characterized by large specific surfaces. The best matching results were obtained for: Redlich−Peterson, Thot and Jovanovic models, and lower for the most frequently used Freundlich and Langmuir models. The adsorption proceeded better from solutions with pH = 6 than with pH = 3 and 10. Two ways of modifying activated carbon were also assessed. A proprietary method of activated carbon modification was proposed. It uses the heating o... [more]
Magnetic Steel Slag Biochar for Ammonium Nitrogen Removal from Aqueous Solution
Gyuhyeon Kim, Youngmo Kim, Sumin Kim, Hyunuk Cho, Jongmoon Park
April 27, 2023 (v1)
Subject: Materials
Keywords: Adsorption, ammonium nitrogen, magnetic biochar, magnetic properties, steel slag
In this study, magnetic steel slag biochar (MSSB) was synthesized from low-cost steel slag waste to investigate the effectiveness of steel slag biochar composite for NH4-N removal and magnetic properties in aqueous solution. The maximum adsorption capacity of NH4-N by MSSB was 4.366 mg/g according to the Langmuir model. The magnetic properties of MSSB indicated paramagnetic behavior and a saturation magnetic moment of 2.30 emu/g at 2 Tesla. The NH4-N adsorption process was well characterized by the pseudo-second order kinetic model and Temkin isotherm model. This study demonstrated the potential of magnetic biochar synthesized from steel slag waste for NH4-N removal in aqueous solution.
Substituent Effects in Kaolinite Flotation Using Dodecylamine: Experiment and DFT Study
Liang Shen, Jiabao Gong, Yifang Liu, Erle Qiao
April 25, 2023 (v1)
Subject: Materials
Keywords: Adsorption, collector, DFT calculation, flotation, kaolinite
The molecular structure of cationic surfactants is closely related to their flotation performance. In this paper, three cationic surfactants with different head group structures were selected as collectors of kaolinite, and the substituent effects were studied by the DFT method. The DFT calculation results showed that increasing the number of substituents in the dodecylamine head group can significantly increase its surface and head group charge. Dodecylamine has the lowest LUMO orbital energy, so dodecylamine has the strongest electron attraction ability and the strongest interaction with kaolinite. Electron density differential showed that there was an area of electron aggregation between the collector and the surface of the kaolinite. The interaction energy of DDA on kaolinite surfaces was greater than that of the other two collectors, indicating that the adsorption of DDA on the surface of kaolinite was more stable. Flotation results showed that higher a kaolinite yield was obtaine... [more]
Performance Analysis of Variable Mode Adsorption Chiller at Different Recooling Water Temperatures
Ahmad A. Alsarayreh, Ayman Al-Maaitah, Menwer Attarakih, Hans-Jörg Bart
April 21, 2023 (v1)
Keywords: Adsorption, adsorption cooling, mass recovery, SAPO-34, variable mode, zeolite
Adsorption cooling can recover waste heat at low temperature levels, thereby saving energy and reducing greenhouse gas emissions. An air-cooled adsorption cooling system reduces water consumption and the technical problems associated with wet-cooling systems; however, it is difficult to maintain a constant recooling water temperature using such a system. To overcome this limitation, a variable mode adsorption chiller concept was introduced and investigated in this study. A prototype adsorption chiller was designed and tested experimentally and numerically using the lumped model. Experimental and numerical results showed good agreement and a similar trend. The adsorbent pairs investigated in this chiller consisted of silicoaluminophosphate (SAPO-34)/water. The experimental isotherm data were fitted to the Dubinin−Astakhov (D−A), Freundlich, Hill, and Sun and Chakraborty (S−C) models. The fitted data exhibited satisfactory agreement with the experimental data except with the Freundlich m... [more]
Design and Large Temperature Jump Testing of a Modular Finned-Tube Carbon−Ammonia Adsorption Generator for Gas-Fired Heat Pumps
Steven Metcalf, Ángeles Rivero-Pacho, Robert Critoph
April 20, 2023 (v1)
Keywords: active carbon, Adsorption, ammonia, heat pump
Gas-fired heat pumps are a potential replacement for condensing boilers, utilizing fossil-fuel resources more efficiently and reducing the amount of biogas or hydrogen required in sustainable gas grids. However, their adoption has been limited due to their large size and high capital cost, resulting in long payback times. For adsorption-based heat pumps, the major development challenge is to maximize the rate of heat transfer to the adsorbent, whilst minimizing the thermal mass. This work develops a modular finned-tube carbon−ammonia adsorption generator that incorporates the adsorbent in highly compacted 3-mm layers between aluminum fins. Manufacturing techniques that are amenable to low cost and high-volume production were developed. The module was tested using the large temperature jump (LTJ) method and achieved a time constant for adsorption and desorption of 50 s. The computational model predicted that if incorporated into two adsorption generators of 6 L volume each, they could b... [more]
Recent Advances in Covalent Organic Frameworks for Heavy Metal Removal Applications
Maria-Anna Gatou, Panagiota Bika, Thomas Stergiopoulos, Panagiotis Dallas, Evangelia A. Pavlatou
April 20, 2023 (v1)
Subject: Environment
Keywords: Adsorption, covalent organic frameworks, environmental remediation, heavy metals, wastewater treatment
Covalent organic frameworks comprise a unique class of functional materials that has recently emerged as a versatile tool for energy-related, photocatalytic, environmental, and electrochromic device applications. A plethora of structures can be designed and implemented through a careful selection of ligands and functional units. On the other hand, porous materials for heavy metal absorption are constantly on the forefront of materials science due to the significant health issues that arise from the release of the latter to aquatic environments. In this critical review, we provide insights on the correlation between the structure of functional covalent organic frameworks and their heavy metal absorption. The elements we selected were Pb, Hg, Cr, Cd, and As metal ions, as well as radioactive elements, and we focused on their removal with functional networks. Finally, we outline their advantages and disadvantages compared to other competitive systems such as zeolites and metal organic fra... [more]
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