Selection Of Suitable Adsorbent Research Articles

A FAIR comparison of activated carbon, biochar, cyclodextrins, polymers, resins, and metal organic frameworks for the adsorption of per- and polyfluorinated substances

Per- and polyfluorinated substances (PFAS) have complex sorption behaviors, complicating removal from water and selection of suitable adsorbents. We evaluated adsorption of 44 PFAS across four adsorbent groups: activated carbon and biochar (AC and BC), cyclodextrin-based adsorbents (cyclodextrins), polymer-based adsorbents and resins, and inorganic adsorbents and metal organic frameworks (MOFs). We analyzed over 500 adsorption coefficients (Kd) from literature, calculated at aqueous equilibrium concentration of 1 ± 0.3 µg/L under comparable experimental conditions. On average, Kd of AC and BC exceeded 107 L/kg for PFAS with C-F bonds > 7, unlike other adsorbents with Kd < 107. This trend holds for C-F bonds ≥ 4. Cyclodextrins, polymer-based adsorbents and resins outperform AC and BC for C-F bonds < 4. For AC and BC, Kd follows the order PFOS>PFOA>PFBS>PFBA, with adsorption increasing with increasing point of zero charge of the adsorbent. For AC and BC, as well as cyclodextrins, Kd values were related to PFAS hydrophobicity and steric properties. Additionally, adsorption was influenced by head group type, non-fluorinated carbon atoms, and the presence of oxygen and/or chlorine in the PFAS. No clear relationship was found for the other adsorbents. Adsorption prediction using a Random Forest Regressor and literature data was feasible for AC and BC, but not for other adsorbents. Cyclodextrins outperform AC and BC for removing PFAS across varying mobilities from water, whereas AC and BC are superior for low mobility PFAS. To support further data use all data and code used are freely available, following FAIR data principles.

Recent research progress on modified activated carbon from biomass for the treatment of wastewater: A critical review

AbstractWater is one of the most vital substances on the planet that supports and sustains life. One of the most crucial challenges of our time is water. It is a basic need for all living beings. Worldwide, a large amount of wastewater is produced daily from home and industrial sources, creating problems such a water shortage and environmental degradation. Water that has already been utilized is called wastewater. It has been observed that the wastewater released varies in composition according to the kind of industry and the municipal sources. Microorganisms, heavy metals, organic pollutants, pesticides, phthalates, polycyclic aromatic hydrocarbons, emerging contaminants, and potentially dangerous wastes are all present in it. Among the most effective methods for removing these contaminants in recent times is the adsorption phenomenon. The presence of various contaminants in wastewater can be efficiently reduced by the simple, efficient, and affordable process of adsorption. Selection of suitable adsorbent is the crucial technique in this operation of adsorption. A versatile adsorbent is activated carbon (AC). Their maximum surface reactivity, large surface area, and microporous form are what give them their adsorptive capabilities. To enable recovery and filter, eliminate, or change the toxic components from gases and liquid solutions, they are used to purify, decolorize, deodorize, dechlorinate, separate, and concentrate. As a result, a variety of industries are interested in AC for the process of adsorption. This review paper briefs the characteristics of AC and their preparation techniques. It discusses the numerous approaches for modifying the surface of AC with significant adsorption capability. It also emphasizes the usage of AC with the elimination of different toxins found in waste water.

A neural recommender system for efficient adsorbent screening

Adsorption is widely used for gas separation and storage. Its performance relies heavily on the selection of suitable adsorbents. In this work, a data-driven neural recommender system is developed for a preliminary adsorbent screening. Over 32,000 single-component isotherms are retrieved from the NIST isotherm database. After a series of filtering steps, 16,470 isotherms related to gaseous adsorbates are obtained and fitted with the dual-site Langmuir sorption isotherm model. Based on these data, a 90 × 1261 sparse matrix is generated. The rows represent adsorbates at specific temperature and pressure. Each column denotes a certain adsorbent. Matrix elements are the corresponding adsorption uptakes. Based on the known entries in the matrix, the neural collaborative filtering method is employed to construct a neural recommender system. The resulting recommender system is utilized to impute the missing elements in the matrix. Finally, the completed matrix is applied to identify promising adsorbents for methane storage and ethene/ethane separation.

A facilely synthesized polyanionic gel adsorbent with high adaptability and new adsorption effects for purification of Cu(II)‐containing wastewater

AbstractBACKGROUNDCu(II)‐containing wastewater causes serious pollution of the water environment. Adsorption is one of the most commonly used water purification methods, with the selection of suitable adsorbents being the key factor. This motivates the development of new efficient adsorbents to purify Cu(II)‐containing wastewater.RESULTSA highly adaptable polyanionic gel (PAG) was synthesized by the facile crosslinking copolymerization of acrylic acid (AA) and triallylmethylammonium chloride (TAMAC) at 65 °C for 0.5 h, followed by a simple neutralization treatment, avoiding the inconvenience of the complex and expensive preparation process required to prepare existing adsorbents. When first used as an adsorbent material, PAG achieved highly efficient purification of a wide concentration range of 10–2000 mg L−1 Cu(II)‐containing wastewater. The PAG adsorption capacity for Cu(II) was 222.2 mg g−1, which was higher than the values of selected existing adsorbent materials (9.50–214 mg g−1), and PAG had the advantages of being eco‐friendly, facilely obtained and regenerable. Also, PAG maintained stable adsorption ability even when the adsorption temperature varied from 30 to 50 °C. Moreover, a series of new adsorption effects were first observed as the key factors for PAG adsorption to achieve high adaptability.CONCLUSIONGenerally, considering the comprehensive performances, PAG would have higher adaptability in the efficient purification of different concentrations and different temperatures of Cu(II)‐containing wastewater. It would thus have better application in different water environments and be regarded as a better adsorbent alternative. © 2019 Society of Chemical Industry

Synthesis and surface gel‐adsorption effect of multidimensional cross‐linking cationic cotton for enhancing purification of dyeing wastewater

AbstractBACKGROUNDDyeing wastewater has caused serious pollution of aquatic environments, and adsorption is one of the most commonly used water‐purification methods with selection of suitable adsorbents being the key factor. These factors motivated us to develop new, more efficient adsorbents to purify dyeing wastewater.RESULTSA surface cross‐linking co‐polymerization of triallylmethylammonium chloride (TAMAC) and grafting cotton with unsaturated bonds (G‐cotton) was designed to obtain multidimensional cationic cotton adsorbent (PT‐cotton) with a high cationic degree of substitution of 0.129. A surface gel‐adsorption effect of the multidimensional cationic construction on cotton surface occurring during PT‐cotton adsorption was discovered resulting in the PT‐cotton having an ultrahigh adsorption capacity for purifying dyeing wastewater. Compared to the untreated cotton, the adsorption capacity of the PT‐cotton was 1344.10 times higher. Compared to the widely used activated carbon, the adsorption capacity of the PT‐cotton was 145.31 times higher, and it was 11.05 and 7.25 times higher, respectively, than that of the similar G‐cotton and polycationic cotton (PF‐cotton) reported in our previous contribution. When PT‐cotton materials were used to fill filter columns, the dye solution flowing through the filter columns immediately became clear, and the dye removal percentage for the PT‐cotton filters reached 96.9%, which was clearly better than that of the activated carbon filter (26.2%). Moreover, the per‐unit amount of water purification from filtering purification of a dye solution using PT‐cotton was 7.02 times higher than that using PF‐cotton.CONCLUSIONSObtained PT‐cotton has a greater potential for application in the purification of dyeing wastewater than the existing adsorbent materials. © 2018 Society of Chemical Industry

Development of porous structured polyvinyl alcohol/zeolite/carbon composites as adsorbent

Adsorption is a separation process that has higher energy efficiency than others. Analyzing the nature of the adsorbate and the selection of suitable adsorbent are key success in adsorption. The performance of the adsorbent can be modified either physically or chemically to obtain the efficiency and effectiveness of the adsorption, this can be facilitated by using a composite adsorbent. In this study, we have conducted the preparation process of a polyvinyl alcohol (PVA)/zeolite/carbon composites. The resulting adsorbent composites are dedicated for ethanol – water dehydration proposes. The composites were prepared using cross-linked polymerization method followed by supercritical fluid extraction (SFE) to obtain the porous structured upon drying process. The characterization of the functional groups and morphology were performed by using Fourier Transform Infra-Red (FTIR) and Scanning Electron Microscopy (SEM), respectively. The FTIR analysis showed that composite prepared by SFE method formed hydrogen bonding confirmed by the appearance of peaks at 2950 – 3000 cm-1 compared to composite without SFE method, whereas, the results of SEM study showed the formation of three layered structures. On basis of the obtained results, it can be shown that PVA/zeolite/carbon has high potential to be develop further as an adsorbent composite.

Integrated Recovery and Recycling of Homogeneous Catalysts by Reverse Flow Adsorption: Selection of Suitable Adsorbents

A promising concept for the recovery of homogeneous catalysts is Reverse Flow Adsorption. In actual homogeneous catalyzed processes, a homogeneous transition-metal catalyst is at equilibrium with its free transition-metal center and ligands. Therefore, to apply Reverse Flow Adsorption, a combination of two adsorbents has to be used to reversibly adsorb: the transition-metal center and its ligands. The transition-metal center can be adsorbed by a suitable ligand immobilized onto a solid carrier, while the ligand is adsorbed by an immobilized transition-metal. Two groups of potential adsorbents were selected by the Hard and Soft Acid and Base (HSAB) theory for the adsorption of Co(II) and PPh3: (1) phosphor (polymer bound PPh3), sulfur (polymer bound methylsufanylmethyl) and chloride (polymer bound benzylchloride) functionalized adsorbents and (2) metal (Ag+, Co2 + and Na+) functionalized Amberlyst 15. The CoCl2 adsorption decreased, as predicted by the HSAB theory, according to: P > S > Cl. Metal functionalized adsorbents adsorbed the PPh3 with capacities decreasing as predicted by the HSAB theory: Ag+ > Co2 + > Na+. All adsorption interactions proved to be reversible.