Adsorption Technology Research Articles

Advancing gasoline vapor recovery in oil depots: Integrating cooling and adsorption technologies

Advancing gasoline vapor recovery in oil depots: Integrating cooling and adsorption technologies

Decontamination of water contaminated by the herbicide glyphosate through adsorption technology: a critical review

Decontamination of water contaminated by the herbicide glyphosate through adsorption technology: a critical review

Characteristics of Volatile Organic Compounds Emissions and Odor Impact in the Pharmaceutical Industry

Volatile Organic Compounds (VOCs) are not only essential precursors for the formation of ozone and PM2.5, but also hazardous to human health and responsible for unpleasant odors. The pharmaceutical industry has become an important industrial source of VOCs due to China’s large emissions and complex emission chains. In total, 245 VOCs samples were collected and analyzed from 11 typical pharmaceutical companies in Zibo City of the North China Plain, in order to investigate the VOCs emission characteristics and odor impacts. The emission factor for the pharmaceutical industry was 7.97 ± 8.21 g/kg pharmaceuticals, while the main emission links were chimney emissions, equipment sealing leakage, and so on. Finally, considering both purifying efficiency and economic benefits, the multistage absorption (AB) method is most effective for VOCs concentrations below 100 mg/m3, while UV photo-oxygenation combined with adsorption (UVA) is more suitable for concentrations below 300 mg/m3. The Regenerative Thermal Oxidizer (RTO), Catalytic Oxidizer (CO), and Condensation + Adsorption (CA) technologies demonstrated greater stability and efficiency, particularly in the treatment of complex organic pollutants, highlighting their advantages in both VOCs and odor removal at higher concentrations.

3D printing of antimicrobial adsorbents using Mercapto-graphene oxide / chitosan / ε-Polylysine: Elucidating adsorption mechanisms and antimicrobial performance.

Cu2+ in wastewater is hazardous to human health, and adsorption technology can effectively remove heavy metal ions. In this study, sulfhydryl graphene oxide/chitosan/ε-polylysine (SGCS-E) polymeric antimicrobial materials were prepared using 3D printing technology. These materials were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and XPS. The effects of temperature and other influencing factors on the adsorption performance were systematically investigated. The adsorption process followed pseudo-second-order kinetics and the Langmuir model. The maximum adsorption capacity of the adsorbent was 313 mg/g at an initial Cu2+ concentration of 20 mg/L, pH 5, and a temperature of 303.15 K. The study on the adsorption mechanism showed that the adsorption of Cu2+ by SGCS-E was mainly controlled by chemical interactions. Antibacterial experiments showed that SGCS-E has a good growth inhibition effect on E. coli and S. aureus. The antibacterial process of SGCS-E is mainly achieved by interfering with the synthesis of proteins and DNA in bacterial cells. Therefore, SGCS-E can not only adsorb and remove Cu2+ from wastewater but also inhibit the overgrowth of microorganisms in the porous adsorbent and improve its reusability, making it a dual-functional adsorbent-antibacterial material with high stability.

Unlocking the potential of environmentally friendly adsorbent derived from industrial wastes: A review.

With increasing urbanization and industrialization, growing amounts of industrial waste, such as red mud (RM), fly ash (FA), blast furnace slag (BFS), steel slag (SS), and sludge, are being produced, exposing substantial threats to the environment and human health. Given that numerous researchers associate with conventional adsorbents, developing and utilizing industrial wastes derived from adsorption technology still has received limited attention. Utilizing this waste contributes to developing alternative materials with superior performance and significantly reduces the volume of solid waste. The excellent physical and chemical characteristics of these wastes are also investigated in this paper. This review attempts to demonstrate a comprehensive overview of the application of industrial waste-based adsorbent in the adsorption process for removing organic pollutants, dyes, metallic ions, non-metallic ions, and radioactive substances. In addition, industrial waste-based adsorbents are among the most promising and applicable techniques for pollutant removal, offering remarkable adsorption efficiency, rich surface chemistries, reasonable cost, simple operation, and low energy consumption. This review summarizes state-of-the-art advancements in engineered adsorbents (including physical and chemical modifications). It provides a holistic view regarding a comprehensive understanding of the mechanism involved in adsorption for water remediation. The challenges and the prospects for future research in applying these adsorbents are also elucidated, contributing to sustainable waste management and environmental sustainability.

A critical review of Allura red removal from water: advancements in adsorption and photocatalytic degradation technologies, and future perspectives

A critical review of Allura red removal from water: advancements in adsorption and photocatalytic degradation technologies, and future perspectives

Highly efficient MIL-53(Al)@Biomass hybrid for oxytetracycline elimination: Adsorption, LED-induced photocatalysis and pyrolytic recycling

The presence of antibiotics in water discharges represents a hazard for the ecosystems, as it could affect the biota equilibrium at the micro and macroscales. Consequently, it is crucial to develop effective adsorption and oxidation technologies to remove antibiotics from water. Herein, we assessed the effectivity and stability of a metal organic framework-biomass hybrid (MIL-53(Al)@RH) for the removal of oxytetracycline (OTC) via adsorption and photocatalytic degradation. Under equilibrated conditions, the hybrid retained 165 mg g−1 OTC. When adsorption and photocatalytic degradation were arranged in tandem, the system removed 99 % of OTC with a dose of 2.83 mg H2O2/mg OTC. The thermo-kinetic interpretation of the adsorption measurements was well described by Sip´s isotherm and pseudo-second kinetic models, which along with the heat of adsorption (−104.8 kJ mol−1) suggest a chemical interaction between the OTC and MIL-53(Al)@Rice Husk hybrid active centres. The MIL-53(Al)@RH hybrid demonstrated a remarkable stability with an OTC removal above 90 % after 10 operational cycles. Moreover, pyrolysis of OTC-saturated hybrid led to a carbonaceous structure which demonstrated an outstanding OTC adsorption capacity (221 mg g−1 OTC). The results demonstrate that the MIL-53(Al)@RH hybrid presents a significant prospect for combined adsorption-photocatalytic treatment of water bodies contaminated with antibiotics.

Monitoring of the inertization of cargo tanks of LNG class vessels

The results of monitoring the inertization of cargo tanks of vessels intended for the transportation of liquefied natural gas are given. It is determined that the mandatory stage of cargo operations in the port of unloading of liquefied natural gas is the inertization of tanks. It is noted that on gas-carrying vessels, the following sources of inert gases can be: flue gases of vessel's auxiliary boilers; gases generated in the inert gas generator during the burning of liquid fuel in them; directly chemically pure inert gas (usually nitrogen). It is also stated that the inertization of cargo tanks is carried out by one of two methods: either dilution of the gas atmosphere (which is the process of mixing two environments), or replacement of the gas atmosphere (in which the gases supplied to the tank form a dividing layer and gradually displace the residual vapors cargo). The stability and integrity of the dividing layer determines the inertization quality of cargo tanks. Control of the state of the dividing layer in the cargo tank is impossible with optical or visual means of control, which is caused by the opaque environment inside the tank. In this regard, it is proposed to determine the integrity of the separating layer, as well as the level at which it is located in the cargo tank, by measuring the concentration of inert gas in the volume of the tank. Research was carried out on a gas carrier with a cargo capacity of 42,563 m3. Inertization of the vessel's cargo tanks was ensured with the help of nitrogen, which was generated by an inert gas generator using the Pressure Swing Adsorption technology. Nitrogen concentration monitoring in the volume of the cargo tank was performed at levels corresponding to 5 %, 20 %, 50 %, 80 % and 95 % of the tank depth. Research on determining the effect of nitrogen pressure entering the cargo tanks for their inertization on the stability and integrity of the dividing layer was carried out in the range of 0.95–1.05 MPa. The duration of the experiment was 210 minutes, fixation of nitrogen concentration values was performed every 30 minutes. As a result, optimal pressure values were established, according to which the inertization is ensured in the minimum time. The critical pressure values at which the separation layer breaks down were also determined.

Enhanced VOCs adsorption on Group VIII transition metal-doped MoS2: A DFT study

Volatile organic compounds (VOCs) represent a significant category of toxic and harmful air pollutants. Among the various abatement techniques available for VOCs, adsorption technology is widely recognized as a cost-effective solution. In this study, density functional theory (DFT) was employed to calculate and compare the adsorption capacities of six typical VOCs on pristine MoS2 and MoS2 modified with Group VIII (MVIII) transition metals atoms. It is found that MVIII-MoS2 monolayer demonstratesa significant enhancement in adsorption capabilities for VOCsrelative to pristine MoS2. Among these Group VIII transition metals atoms, Fe, Ru and Os atoms exhibited the most significant VOCs adsorption enhancement, with Fe atoms demonstrating a particularly pronounced effect. This suggests a synergistic interaction between the metal dopants and the substrate. Density of states (DOS) and charge density difference analyses provided further insights into the mechanisms underlying improved adsorption capability. Interestingly, the introduction of MVIII atoms results in the emergence of a novel state density within the surface state of MoS2, thereby facilitating enhanced electron transfer between VOCs and the substrate. Charge density difference calculations further corroborated these findings, with certain configurations exhibiting significant electron cloud overlap. Such modification leads to more active electron transfer, thereby increasing the substrate’s affinity for VOC molecules and consequently improving the adsorption efficiency. The findings not only enhance the comprehension of VOC adsorption mechanisms on MoS2 but also underscore the potential of metal-doped two-dimensional materials for environmental applications.

Facile synthesis and biomimetic amine-functionalization of chitosan foam for CO2 capture

A high-performance biomass-based adsorption materials could be the promising trend for CO2 capture and storage technology. However, the direct application of biomass-based porous materials as a CO2 adsorbent with enhanced performance is an emerging issue. Herein, a facile synthesis and a biomimetic strategy were combined to prepare amine-functionalized chitosan foam for CO2 capture, and then a porous biomass is achieved for the application on the environment protection field. Firstly, the chitosan foam was synthesized by the emulsion-templating method at room temperature. Depended on stabilizing n-octane in the chitosan hydrogel with Span 80, a tunable three-dimensional network porous structure was obtained. Subsequently, co-deposition with dopamine (DA) and polyethyleneimine (PEI) was applied to load abundant amine content on the surface of chitosan foam and thereby improving CO2 adsorption capacity. Finally, the as-prepared amine-functionalized chitosan foam exhibited the impressive adsorption capacity of 3.59 mmol/g at 333 K and atmospheric pressure, and the better adsorption selectivity and stability. The results extend the preparation approach of biomass porous materials, and also its application in CO2 adsorption technology.

Adsorbent Properties of Porous Boron Nitride and Activated Carbon: A Comparative Study.

Porous boron nitrides possess beneficial properties such as high thermal and chemical stability which are critical for applications in adsorption processes. In order to assess possible fields of applications, trace-level adsorption isotherms of different hydrocarbons on two synthesized porous boron nitrides and two commercial activated carbons are compared. By normalizing the adsorptive loadings on the micropore surface area, superior adsorption performances of the BN materials on polar and aromatic adsorptives with up to 50% higher loadings compared to the activated carbons can be shown. Nonpolar adsorptives, on the other hand, feature higher specific loadings on the activated carbon. Consequently, the size of the micropore surface appears to be decisive for nonpolar adsorptives, while the higher polarity of the boron nitrides is the dominant influencing factor for the adsorption of polar and aromatic components. For an energetic study of the adsorbents, calorimetric experiments were performed to identify and discuss adsorbent-adsorptive interactions. While the initial heat of adsorption of the nonpolar n-hexane is lower on the boron nitride than on the activated carbon due to a less favorable spatial arrangement, toluene shows comparable values on both adsorbent classes and the polar acetone shows higher values on the polar boron nitride. Considering technical applications in adsorption technology, the thermal stability of the boron nitrides is investigated using spontaneous ignition temperatures and points of initial oxidation. Here, the porous boron nitrides with oxidation temperatures above 900 °C show about 400 °C higher values and thus a significantly higher thermal stability.

DFT based investigations on inherent CO2 adsorption and direct dissociation capability of Ti2C and Nb2C mxenes

Transition metal carbide MXenes, specifically Ti2C and Nb2C, have been investigated for their ability to efficiently adsorb and dissociate CO2 using First Principles Calculations based on Density Functional Theory (FPS-DFT). Pure Ti2C and Nb2C sheets were studied with the adsorption of 1 to 4 CO2 molecules, and the results were analyzed for each case. For 4 CO2 molecules adsorbed on Ti2C and Nb2C sheets, the weight percentage (wt%) ratio was found to be 21.39% and 14.33%, respectively. The Density of States (DOS) analysis revealed that, upon CO2 adsorption, the CO2 molecule dissociates into CO and O atoms on the MXene surface. The CO molecule showed no significant hybridization with the host sheet atoms, whereas the O atom exhibited strong hybridization with the MXene surface. Transition State (TS) profiles illustrated the dissociation steps on both Ti2C and Nb2C surfaces. Phonon calculations confirmed the dynamic stability of both pure and CO2 adsorbed MXenes. Molecular Dynamics (MD) simulations conducted at 900 K indicated uniform temperature and Mean Square displacement (MSD) profiles, suggesting the stability of both pure and CO2 adsorbed MXenes at elevated temperatures, as well as uniform CO2 adsorption behavior. The adsorption energies for Ti2C and Nb2C sheets were calculated to be in the range of -1.89 to -2.77eV, suggesting that the adsorption process is favorable, spontaneous, and predominantly involves chemisorption. These findings indicate that Ti2C and Nb2C MXenes, in their intrinsic forms, are promising candidates for CO2 adsorption and dissociation technologies.

Hierarchical pore-enhanced ion transport and defect-induced dual strong interactions for highly efficient lithium extraction

In the past decade, adsorption method has attracted great attention on the lithium extraction. The key issue in adsorption technology is to develop adsorbents with high adsorption capacity, selectivity, and recycle-stability. Here, the highly efficient metal–organic framework adsorbents were developed for lithium extraction, which were fabricated by the in-situ conversion of MIL-121 in alkali solution. The adsorbent after acid activation, termed as H-CAOMIL, was featured with the hierarchical porosity, enhanced density of free carboxylic groups, and exposed aluminum-oxygen defect sites to enhance the ion transport and provide dual strong interaction for Li+. H-CAOMIL exhibited the remarkable Li+ adsorption capacity (QLi+ = 5.28 mg/g) and selectivity (αKLi = 21.33, αNaLi= 9) from low-concentration lithium-containing solutions. Moreover, the H-CAOMIL can be easily regenerated in weakly acidic solution. Impressively, Li+ adsorption capacity retained at 92 % of the initial capacity even after five adsorption–desorption cycles. Furthermore, the comprehensive characterizations and theoretical calculations indicated that the specific coordination of COO-Li and AlO-Li played a crucial role in the recovery capacity and selectivity of Li+. This work offers precious insights for the future exploration of highly efficient adsorbents for lithium extraction.

Fabricating a Pistachio Nut Shells Activated Carbon + CNTs @ Chitosan (PAC-CNTs @Cs) Composite for Pesticides Attenuation from Agricultural Wastewater

Agriculture is the largest consumer of water resources in Egypt. Pesticides are a major contaminant of agricultural wastewater. Chemical pesticides must be eliminated from wastewater because they accumulate in the soil and water sources. They can be absorbed by specific crops, resulting in a significant impact on human health because they are toxic and carcinogenic. Adsorption technology has been used widely for wastewater treatment due to its effectiveness and low cost. In this study, both microporous activated carbon (PAC) and composite (PAC-CNTs @Cs) were made from pistachio nutshell as agricultural waste and used to remove pesticides from agricultural wastewater. The XRD, TGA, BET, SEM, EDAX and FT-IR techniques were used to characterize the (PAC-CNTs @Cs) composite. The results demonstrate that the maximal PAC removal percentages in synthetic and real samples are 90% and 64%, respectively. While the PAC-CNTs @Cs removal percentage reached 98% and 78% in synthetic and real samples, respectively. Otherwise, the minimum PAC removal percentages in synthetic and real samples are 62% and 57%, respectively. While PAC-CNTs @Cs had minimum removal percentage of 77% and 75% for synthetic and real samples, respectively. The conclusion reached was that PAC-CNTs @Cs had a higher adsorption capacity than PAC.

Experimental study of four-step thermal swing adsorption cycle to upgrade biogas obtained from anaerobic digestion

Biogas is a renewable source of energy that when upgraded can be adopted as a reliable and sustainable alternative. This study evaluates the performance of thermal swing adsorption technology applying resistive heating, in upgrading biogas obtained from anaerobic digestion to biomethane. Commercial coconut shell-based activated carbon was used as an adsorbent in the four-step cycle process to capture carbon dioxide, using a fabricated adsorption model. The influence of minor gas constituents of biogas in carbon dioxide breakthrough curves was analyzed. Dynamic adsorption tests were carried out to evaluate the system performance in carbon dioxide capture. The maximum regeneration temperature of 60 ℃ was found to have peak carbon dioxide concentration of 39% in the waste gas, maximum energy requirements of 0.1538kWh per cycle, and an energy efficiency of 87%. This is a good trade-off between adsorbent recovery and system energy efficiency. The adoption of thermal swing adsorption technology in biogas upgrading systems is a viable alternative for water-deficient regions.

Amidation modified hollow composite microspheres as a self-floating adsorbent for efficient capture of anionic dye DB86 and heavy metal nickel (II).

The co-contamination of dyes and heavy metal ions often used as mordants poses potential risks to environment and public health, and is a challenging problem that needs to be solved in water treatment. Meanwhile, improving the solid-liquid separation capability of adsorbents is of great significance for the application of adsorption technology. Herein, amidation modified hollow composite microspheres were prepared using hollow glass microsphere (HGM) as matrix through hydrolysis and condensation of silane coupling agent (A-1100) and subsequent amidation reaction. The material (HGMNE) not only exhibited good adsorption performance for DB86 and Ni2+ but also had stable self-floating capability. The adsorption of DB86 by HGMNE is mainly carried out by the electrostatic interaction between positively charged quaternary amine nitrogen and negatively charged DB86, while the adsorption of Ni2+ is achieved by the carboxyl group in EDTA group through complexation interaction to adsorb Ni2+ to form Ni complex. This research not only is devoted to the utilization of HGMNE to achieve the co-removal of DB86 and Ni2+ and flexible self-floating solid-liquid separation but also verifies the feasibility and applicability of the modification method of introducing organic adsorption functional groups through amidation reaction, so as to expand the preparation path of HGM-based adsorbents.

Unveiling Temperature-Induced Structural Phase Transformations and CO2 Binding Sites in CALF-20.

The increase in atmospheric carbon dioxide concentration linked to climate change has created a need for new sorbents capable of separating CO2 from exhaust gases. Recently, an easily produced metal-organic framework, CALF-20, was shown to withstand over 450,000 adsorption/desorption cycles in steam and wet acid gases. Further development and industrial application of such materials require an understanding of the observed processes. Herein, we demonstrate that conditioning as-synthesized CALF-20 single crystal transforms it into a different phase, γ-CALF-20. The transformation resulted in significant structural changes, including the binding of water molecules to Zn(II), accompanied by a reduction of 9% in the unit cell volume. Our experimental findings were supported by the energy-volume dependence of CALF-20 in the presence and absence of water molecules calculated from density functional theory. We have also monitored the sorption process of the dominant greenhouse gas, CO2, on the initial phase of CALF-20 at atomic resolution using in situ single-crystal X-ray diffraction under specific pressure. The new understanding of CALF-20 chemistry from these studies should facilitate development of novel sorbents for gas adsorption technologies.

A novel magnetic S/N co-doped tea residue biochar applied to tetracycline adsorption in water environment

The issue of tetracycline (TC) contamination has attracted widespread attention. Adsorption technology has great potential for application in the field of TC remediation. This study achieved the production of nitrogen self-doped biochar using waste tea leaves as raw materials, and further improved its TC removal effect by doping sulfur elements. A recyclable high-performance TC adsorbent magnetic S/N co-doped tea residue biochar (MSNB) was obtained through ferromagnetic modification, which could be used as an effective TC adsorbent. The effects of MSNB dosage and initial solution pH on TC removal were evaluated. The recovery performance of MSNB adsorbent on TC was studied. The maximum adsorption performance at 298 K calculated using the Langmuir model was 140.76 mg g−1. The fitting results of adsorption kinetics indicated that chemical adsorption was the main factor affecting the adsorption reaction. After 5 cycles of adsorption, the removal of TC by MSNB remained above 88.30 %. This study could provide theoretical support for the treatment of tetracycline wastewater by biochar adsorption.

Investigation on novel chitin and chitosan from dung beetle Heteronitis castelnaui (Harold, 1865) and its potential application for organic dyes removal from aqueous solution

Chitosan, a natural polysaccharide, has attracted considerable attention as an environmentally friendly and highly efficient adsorbent for dye removal. It is usually produced by deacetylation or partial deacetylation of chitin. However, conventional sources of chitin and chitosan are limited, prompting the need for alternative sources with improved adsorption capabilities. Herein, this study focuses on exploring a novel chitin and chitosan source derived from the dung beetle and evaluates its potential for organic dye removal from aqueous solutions. The research involves the extraction and characterization of chitin and chitosan from dung beetle Heteronitis castelnaui (Harold, 1865) using various analytical techniques, including SEM, FT-IR, TGA, XRD, NMR, deacetylation degree and elemental analysis. The chitosan obtained was used for the formation of hydrogels with sodium alginate via cross-linking with calcium chloride. And then the prepared hydrogels were evaluated for its adsorption capacity through batch adsorption experiments using methylene blue as a model pollutant. The adsorption capacity for methylene blue was 1294.3 mg/g at room temperature with solution pH = 12, MB concentration of 1800 mg/L. Furthermore, the kinetics of the adsorption process were analyzed using pseudo-first-order and pseudo-second-order models to understand the rate of adsorption. The maximum adsorption capacities were determined using Langmuir and Freundlich isotherm models. This study provides valuable insights for the development of sustainable dye adsorption technologies, specifically investigating a novel chitosan source derived from the dung beetle.

A multi-node thermodynamic model on temperature-vacuum swing adsorption (TVSA) for carbon capture: Process design and performance analysis

The adsorption technology plays a significant role in the carbon capture domain for mitigating the CO2 emissions, whereas the heterogeneous character is presented in practical adsorption process. In this study, a multi-node thermodynamic model is established for temperature-vacuum swing adsorption (TVSA) considering the end non-uniform adsorption. It shows superior performance for the assessment of practical TVSA cycle compared with lumped model. Through the influence analysis of different operation parameters based on multi-node model, specific exergy consumption increases from 41.6 to 62.4 kJ/mol caused by simultaneous drop of heat consumption and lift of work consumption as feed pressure raises from 1.0 to 3.0 bar. Exergy efficiency ranges between 13.8 % and 15.0 % as CO2 concentration increases from 10 % to 20 %. However, those under ppm-level are below 0.86 %, presenting the higher exergy consumption but lower desorption capacity represented for direct air capture. The heat consumption of front half part of adsorption bed is 39.7 % higher than the latter one, proving the potential cascaded desorption of subzone heating is superior for reducing the energy consumption. Furthermore, exergy consumption is lifted due to enhancement of work consumption of vacuum pump as vacuum pressure reduces from 1.0 to 0.02 bar, resulting exergy efficiency drops from 19.6 % to 13.4 %.