Organic Adsorption Research Articles

Comprehensive evaluation of the catalytic activity of alpha-ferric oxide in photocatalysis, Fenton-like and photo-Fenton systems for organics degradation: Performance and in-depth mechanism consideration

Although alpha-ferric oxide (α-Fe2O3) has been widely used in photocatalysis, Fenton-like and photo-Fenton systems for organics degradation, its catalytic activity is still necessary to be evaluated scrupulously in full consideration of organics adsorption and homogeneous Fenton oxidation. In this work, nanoscale α-Fe2O3 was prepared by the direct calcination of FeCl3·6 H2O, and its true catalytic activity in photocatalysis, Fenton-like and photo-Fenton systems was evaluated by the degradation of rhodamine B (RhB) and tetracycline (TC). It was found that the activity of α-Fe2O3 in Fenton-like and photo-Fenton systems at pH 3.0 was higher than that at pH 7.0 and pH 9.0. Compared with photocatalysis and Fenton-like systems, photo-Fenton system exhibited greater organics degradation performance. In the photo-Fenton system, photocatalytic reactions can not only degrade organics directly and accelerate the redox cycle of Fe(II)/Fe(III), but also supply more active sites to promote H2O2 activation. Photocatalytic reactions caused more Fe leached, whereas dissolved Fe could enhance degradation performance significantly even at a very low concentration (0.15 mg L–1). An interesting result was that the increase of solution pH enhanced H2O2 decomposition in the photo-Fenton system, but the degradation performance decreased obviously. Overall, α-Fe2O3 does not have high activity in photocatalysis and Fenton-like systems, and its heterogenous Fenton-like activity may be overestimated in many references. α-Fe2O3 is more suitable to be applied in photo-Fenton system to remove organic pollutants from acidic wastewaters considering H2O2 utilization efficiency.

Modified hemp fibers as a novel and green adsorbent for organic dye adsorption: adsorption, kinetic studies and modeling

Synthetic dyes represent a serious hazard to aquatic environments. Many approaches for eliminating these contaminants have been devised and applied. This manuscript reports the production of a novel, low-cost and ecologically friendly bioadsorbent based on hemp fibers that are functionalized with graphite oxide through bridging with an organosilane. Methylene blue was selected as a typical pollutant to be removed from wastewaters. The adsorbent was characterized through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared (FTIR) analysis. An investigation of the effects of pH and temperature on the adsorption process was carried out. The adsorption capacity increased with increasing contact time as well as with the temperature, proving that the process shows endothermic behavior. Moreover, the process was found to be dependent on the pH level and, to corroborate the collected results, the point of zero charge was evaluated. The maximum adsorption capacity was found to be 57 mg/g, which was achieved with the following parameters: pH = 7.5, T = 80 °C and an initial dye concentration equal to 5 mg/L. Reusability studies showed a 15% decrease in adsorption capacity after 30 adsorption tests, proving the possibility of reusing the produced adsorbent without any great decay in performance. Finally, a potential adsorption mechanism is reported and discussed. The reported results prove that it is feasible to apply the designed adsorbent of organic dyes to the purification of wastewaters.Graphical abstract

Efficient photocatalytic degradation of antibiotics by binary heterojunction complex boron subphthalocyanine bromide/bismuth oxychloride

The development of stable and efficient heterojunction photocatalysts for wastewater environmental purification exhibits a significant challenge. Herien, a promising binary heterojunction complex comprising boron subphthalocyanine bromide/bismuth oxychloride (SubPc-Br/BiOCl) was successfully synthesized using the hydrothermal method, which involved the self-assembled of SubPc-Br on the surface of BiOCl via intermolecular π-π stacking interactions to compose an electron-transporting layer. The photocatalytic efficiency of SubPc-Br/BiOCl for the degradation of tetracycline and the minocycline exhibited a substantial improvement of 29.14% and 53.72%, respectively, compared to the original BiOCl. Experimental characterization and theoretical calculations elucidated that the enhanced photocatalytic performance of the SubPc-Br/BiOCl composite photocatalysts stemmed from the S-scheme electron transport mechanism at the interface between BiOCl and SubPc-Br supramolecules, which broadened the visible light absorption range, increased the carrier molecular efficiency, and accelerated the carriers. Furthermore, molecular dynamic (MD) simulations provided insights into the action trajectories of the two semiconductors, revealing that the presence of SubPc-Br enhances the water and organic pollutant adsorption capabilities of the BiOCl surface within the supramolecular array system. In conclusion, the synthesis and analysis of the binary heterojunction complex SubPc-Br/BiOCl yield valuable insights into the efficient photocatalytic degradation of antibiotics, holding great promise for diverse environmental applications.

Amidation-Reaction Strategy Constructs Versatile Mixed Matrix Composite Membranes towards Efficient Volatile Organic Compounds Adsorption and CO2 Separation.

Mixed matrix composite membranes (MMCMs) have shown advantages in reducing VOCs and CO2 emissions. Suitable composite layer, substrate, and good compatibility between the filler and the matrix in the composite layer are critical issues in designing MMCMs. This work develops a high-performance UiO-66-NA@PDMS/MCE for VOCs adsorption and CO2 permea-selectivity, based on a simple and facile fabrication of composite layer using amidation-reaction approach on the substrate. The composite layer shows a continuous morphological appearance without interface voids. This outstanding compatibility interaction between UiO-66-NH2 and PDMS is confirmed by molecular simulations. The Si─O functional group and UiO-66-NH2 in the layer leads to improved VOCs adsorption via active sites, skeleton interaction, electrostatic interaction, and van der Waals force. The layer and ─CONH─ also facilitate CO2 transport. The MMCMs show strong four VOCs adsorption and high CO2 permeance of 276.5 GPU with a selectivity of 36.2. The existence of VOCs in UiO-66-NA@PDMS/MCE increases the polarity and fine-tunes the pore size of UiO-66-NH2, improving the affinity towards CO2 and thus promoting the permea-selectivity for CO2, which is further verified by GCMC and EMD methods. This work is expected to offer a facile composite layer manufacturing method for MMCMs with high VOC adsorption and CO2 permea-selectivity.

Comparing different versions of the Yoon-Nelson model in describing organic micropollutant adsorption within fixed bed adsorbers.

The Yoon-Nelson model serves as a widely used tool for describing the breakthrough behavior of organic micropollutants within fixed bed adsorbers. This study aims to augment its modeling efficacy through two proposed refinements found in the literature: a logarithmic transformation and the incorporation of steric hindrance effects. We systematically evaluated the original Yoon-Nelson model alongside the modified versions, using breakthrough data associated with micropollutant adsorption on solid materials. Three distinct cases were scrutinized: (1) caffeine adsorption on activated carbon; (2) tetracycline adsorption on hierarchical porous carbon; and (3) diclofenac adsorption on organoclay. While all three models demonstrated comparable performance with highly symmetric breakthrough data in case 1, their efficacy diverged significantly when confronted with strongly asymmetric breakthrough data in cases 2 and 3. The original Yoon-Nelson model and the logarithmically modified version fell short in accurately representing these intricate breakthrough curves. In contrast, the version incorporating steric hindrance effects showcased substantial accuracy, outperforming other models in capturing the complexities of asymmetric breakthrough data. This advancement markedly enhances the modeling accuracy and versatility of the Yoon-Nelson model, particularly in assessing the dynamic behavior of organic micropollutants within fixed bed adsorbers.

First-principles investigation on molecular adsorption on 2D perovskite toward optoelectronic application

Halide perovskite materials have received attention for optoelectronic applications, and it is promising to further engineer the perovskite systems via surface molecular adsorption to improve optoelectronic properties. In this study, we comprehensively investigate atomic structures and properties of surface molecule-modified low-dimensional halide perovskite systems represented by Cs2PbBr4 via first-principles calculations. The calculation pinpoints the effectiveness of molecular adsorption to fine tune the structural and electronic properties of low-dimensional halide perovskite material, which can be stabilized via interfacial secondary bonds such as anion···π, halogen bond and hydrogen bond interactions. Noteworthily, the anion···π interaction is almost ubiquitous in the aromatic molecule/perovskite systems in the present study assuming the adsorption mode is horizontal, signifying the versatility of anion···π interaction to functionalize low-dimensional halide perovskite surfaces. In addition, the amine-containing molecules tend to initiate molecule → perovskite interfacial charge transfer direction upon light excitation while most other organic molecules favors halogen → lead electron transfer process inside the perovskite substrate. Importantly, the polaron calculations suggest the possibility of forming large polarons to protect charge transport via effective electron- and hole-phonon coupling upon molecular adsorption. This study highlights the effectiveness of organic molecule adsorption to fine tune optoelectronic properties of low-dimensional perovskite systems via the formation of interfacial secondary bonds.

Surface stress can initiate environment-assisted fracture in metals.

Controlling environmental effects in surface plasticity/fracture of metals is of interest for areas as diverse as manufacturing processes, product performance, and structural safety. The key to controlling these effects is understanding the effect of adsorbates on surface energy (γ) and surface stress (f). While γ has been well studied, the role of surface stress has received much less attention. We characterize surface stress induced in metals by adsorption of organic monolayers. Linear alkanoic acids of varying chain length (3-18) are deposited by molecular self-assembly onto one side of an aluminum cantilever, several centimeters in length. The surface stress is estimated from in situ measurement of the cantilever deflection. We find that the organic adsorbates induce large surface stress of -4 to +30N/m. Furthermore, we show that f may be tuned by varying adsorbate-molecule chain length. The stress data explain beneficial embrittlement of metal surfaces by organic adsorbates in cutting and comminution processes, and point to a critical role, hitherto ignored, for f in environment assisted cracking (EAC) phenomena. Our results suggest opportunities for utilizing controlled environment-assisted fracture as an aid-fracture as a friend-to enhance material removal processes, apart from using surface stress itself as an experimental probe to explore various manifestations of EAC.

Adjusting the electronic behavior of two-dimensional GeC through organic molecular adsorption

Organic molecule adsorption is an effective method for regulating the electronic performance of two-dimensional materials. This article investigates the construction and electronic properties of organic molecules (Tetracyanoquinodimethane (TCNQ, C12H4N4), Tetracyanoethylene (TCNE, C6N4), and Tetrathiafulvalene (TTF, C6H4S4)) adsorbed on GeC monolayer based on density functional theory (DFT). Research has shown that after organic molecules adsorbed by monolayer GeC, the band structure of the GeC host basically remains. Besides, TCNQ and TCNE molecules, as electron acceptors, induce shallow acceptor states in GeC, and the doping gap of the adsorption system is very small, exhibiting effective p-type doping behavior. TTF molecule, as an electron donor, induces deep receptor states on monolayer GeC and exhibits n-type doping behavior. The partial charge density and the density of states indicate that the impurity energy levels present in the band structure are mainly provided by organic molecules. The current-voltage (I–V) curves reveal that after organic molecules adsorbed by monolayer GeC, the transport characteristic response of the n-type adsorption behavior system is relatively effective compared to that of the p-type adsorption behavior system. Additionally, organic molecules can provide GeC with extra carriers or electrons, which allows the work function to be adjusted within the range of 3.99 eV–5.30 eV. Therefore, our work provides a theoretical foundation for studying p-type doping nano semiconductors and prospective applications for GeC-based nanoelectronic devices.

Development and application of a new deep eutectic solvent based magnetic metal–organic framework adsorbent for the detection of fluorotelomer alcohols in edible oils

The enrichment of per- and polyfluoroalkyl substances (PFASs) poses significant challenges for environmental and food safety monitoring, given their toxic and persistent nature, highly fluorinated character, and low concentration. This study focuses on the construction of a new deep eutectic solvent (DES)-functionalized magnetic metal–organic framework (MOF) adsorbent for fluorotelomer alcohols (FTOHs) analysis in foods. The DES, composed of levulinic acid and trifluoromethoxylbenzene, was modified onto the surface of magnetic UiO-66-NH2 to enable the specific adsorption of FTOHs during the pretreatment process, which was then followed by GC–MS analysis. The method exhibited a limit of detection (LOD) ranging from 31.51 to 185.76 pg g – 1 with satisfactory recoveries (73.83 %-128.55 %), and was successfully used in detecting FTOHs in 12 edible oils samples with the concentrations ranging from 401.89 to 8006.18 pg g − 1. The proposed adsorbent exhibited significantly improved enrichment performance for PFASs, primarily attributed to the cooperative enhancement of double hydrogen-bonding interactions and fluorine affinity via the elucidation of 1H nuclear magnetic resonance (1H NMR), 19F NMR, and quantum chemical calculations. This study provided new insights and directions for the design and fabrication of selective materials to pretreatment ultra-trace emerging contaminants in complex matrices.

How aromatic dissolved organic matter differs in competitiveness against organic micropollutant adsorption

Activated carbon is employed for the adsorption of organic micropollutants (OMPs) from water, typically present in concentrations ranging from ng L−1 to μg L−1. However, the efficacy of OMP removal is considerably deteriorated due to competitive adsorption from background dissolved organic matter (DOM), present at substantially higher concentrations in mg L−1. Interpreting the characteristics of competitive DOM is crucial in predicting OMP adsorption efficiencies across diverse natural waters. Molecular weight (MW), aromaticity, and polarity influence DOM competitiveness. Although the aromaticity-related metrics, such as UV254, of low MW DOM were proposed to correlate with DOM competitiveness, the method suffers from limitations in understanding the interplay of polarity and aromaticity in determining DOM competitiveness. Here, we elucidate the intricate influence of aromaticity and polarity in low MW DOM competition, spanning from a fraction level to a compound level, by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry. Anion exchange resin pre-treatment eliminated 93% of UV254-active DOM, predominantly aromatic and polar DOM, and only minimally alleviated DOM competition. Molecular characterization revealed that nonpolar molecular formulas (constituting 26% PAC-adsorbable DOM) with medium aromaticity contributed more to the DOM competitiveness. Isomer-level analysis indicated that the competitiveness of highly aromatic LMW DOM compounds was strongly counterbalanced by increased polarity. Strong aromaticity-derived π-π interaction cannot facilitate the competitive adsorption of hydrophilic DOM compounds. Our results underscore the constraints of depending solely on aromaticity-based approaches as the exclusive interpretive measure for DOM competitiveness. In a broader context, this study demonstrates an effect-oriented DOM analysis, elucidating counterbalancing interactions of DOM molecular properties from fraction to compound level.

Mechanisms of metal wettability transition and fabrication of durable superwetting/superhydrophilic metal surfaces

Maintaining superhydrophilicity on metal surfaces is challenging due to the inevitable surface adsorption of airborne organics after exposure to ambient air. In this study, we aim to elucidate the mechanisms underlying the persistence of surface superhydrophilicity and propose a technique for the preparation of durable superwetting/superhydrophilic metal surfaces. The effects of atmospheric organic properties, including the type of functional groups and the length of the carbon chain, on the rate of wettability transition and the final surface wettability after the surface adsorption are first investigated. Molecular dynamics simulation is used to explain why long-chain organics can lead to more marked wettability transitions. The liquid wetting and organic diffusion on textured surfaces are then analyzed, which proves that conventional surface structures with only single-scale structural features are challenging to achieve long-lasting superhydrophilicity. Finally, an in-situ laser deposition technique is proposed to fabricate micro-nano composite porous structures, in which the microstructures promote liquid wetting and the nanostructures inhibit organic diffusion. The prepared surfaces exhibited a 54-fold enhancement in the duration of surface superhydrophilicity compared to conventional nanostructures. Our results help to understand the mechanisms of durable superhydrophilicity, which are beneficial for the practical applications of superwetting/superhydrophilic surfaces.

A new approach of simultaneous adsorption and regeneration of activated carbon to address the bottlenecks of pharmaceutical wastewater treatment

This study proposes a sustainable approach for hard-to-treat wastewater using sintered activated carbon (SAC) both as an adsorption filter and as an electrode, allowing its simultaneous electrochemical regeneration. SAC improves the activated carbon (AC) particle contact and thus the conductivity, while maintaining optimal liquid flow. The process removed 87 % of total organic carbon (TOC) from real high-load (initial TOC of 1625 mg/L) pharmaceutical wastewater (PWW), generated during the manufacturing of azithromycin, in 5 h, without external input of chemicals other than catalytic amounts of Fe(II). Kinetic modelling indicated that adsorption was the dominant process, while concomitant electrochemical degradation of complex organics first converted them to short-chain acids, followed by their full mineralization. In-situ electrochemical regeneration of SAC, taking place at the same time as the treatment, is a key feature of our process, enhancing its performance and ensuring its stable operation over time, while eliminating cleaning downtimes altogether. The energy consumption of this innovative process was remarkably low at 8.0×10−3 kWh gTOC−1. This study highlights the potential of SAC for treating hard-to-treat effluents by concurrent adsorption and mineralization of organics.

Novel Zr-based MOF with Ortho-hydroxyl group selectively traps germanium from aqueous media

Recovery of Ge(IV) from solution is of increasing interest. A novel metal–organic framework adsorbent (Ma-Zr-MOF) is synthesized using mucic acid. A series of characterizations prove the successful synthesis of Ma-Zr-MOF. The maximum adsorption capacity of germanium by Ma-Zr-MOF is 82.06 mg/g at 298 K and pH 6.0, which is better than some of the previously reported adsorbents. The adsorption of germanium ions by Ma-Zr-MOF is in accordance with the pseudo-second-order kinetics and Langmuir isothermal models, the adsorption type is single-layer chemical adsorption on a uniform surface. Thermodynamic calculations yield that the adsorption process is endothermic and spontaneous. Ma-Zr-MOF has good selectivity and anti-interference, and maintains repeatability after five adsorption and desorption cycles. Based on the experimental analysis and density functional theory (DFT) calculations, it is concluded that the Ortho-hydroxyl group played an important role in the adsorption of germanium and that the adsorption mechanism included chelation and ion exchange. In conclusion, Ma-Zr-MOF is proved to be a feasible material for the recovery of Ge(IV) from aqueous media.

Experimental and modeling study of volatile organic compounds adsorption over zeolitic monolith adsorbent

In this study, a coupled mass and momentum model is developed and solved to describe the dynamic adsorption of a single adsorbate over honeycomb structured zeolite under industrial operating conditions. The Linear Driving Force approximation was used to predict the kinetics of adsorption to the solid-phase mass transfer and Navier Stokes equations were solved both radially and axially under laminar flow conditions through the honeycomb channels. To investigate the effect of key input parameters on model results, a sensitivity analysis was performed. Modeling and experimental results compared the effects of different initial concentrations and gas stream face velocities under a range of conditions to determine adsorption capacity, removal efficiency, and the 5% breakthrough time. Overall, the model output was in good agreement (less than 5% mean absolute relative error in concentration) with the experimental results under industrially relevant operating conditions. Modeling results illustrated that the radial velocity distribution over the monolith channels has an important effect on the shape of the breakthrough curve as well as the 5% breakthrough time. Both experimental results and modeling predictions showed that the long tails of the adsorption breakthroughs were the result of the non-uniform flow distribution, which resulted in delayed saturation of the outer honeycomb channels.

Impact of non-aged and UV-aged microplastics on the formation of halogenated disinfection byproducts during chlorination of drinking water and its mechanism

Microplastics (MPs) are ubiquitously present in source water and undergo ultraviolet (UV) aging in aquatic environments before entering drinking water treatment plants. The presence of MPs in drinking water can impact the formation of halogenated disinfection byproducts (DBPs) during chlorine disinfection, yet the exact effect of MPs on DBP formation remain unclear. In this study, we conducted an investigation into the influence of non-aged and UV-aged MPs on halogenated DBP formation in drinking water and unveiled the underlying mechanisms. In comparison to source water samples devoid of MPs, the total organic halogen concentration was reduced by 19%–43% and 4%–13% in the drinking water samples containing non-aged and aged MPs, respectively. The differing effects on halogenated DBP formation can be attributed to the alternation in physical and chemical characteristics of MPs following UV aging. Aged MPs exhibited larger surface area with signs of wear and tear, heightened hydrophilicity, surface oxidation, increased oxygen-containing functional groups and dechlorination during the UV aging process. Both non-aged and aged MPs possess the capability to adsorb natural organic matter, leading to a reduction in the concentration of DBP precursors in the source water. However, the release of organic compounds from aged MPs outweighed the adsorption of organics. Furthermore, as a result of the surface activation of MPs through the UV aging process, the aged MPs themselves can also serve as DBP precursors. Consequently, the presence of halogenated DBP precursors in source water increased, contributing to a higher level of DBP formation compared to source water containing non-aged MPs. Overall, this study illuminates the intricate relationship among MPs, UV aging, and DBP formation in drinking water. It highlights the potential risks posed by aged MPs in influencing DBP formation and offers valuable insights for optimizing water treatment processes.

Regeneration of sedimentary phosphorus and iron in a large seasonally hypoxic estuary deciphered by 224Ra/228Th disequilibria

Using a 224Ra/228Th disequilibrium approach, we demonstrate in this study that benthic fluxes of dissolved inorganic phosphorus (DIP) in the seasonally hypoxic Yangtze River Estuary were largely manipulated by two counteracting processes: the decomposition of sedimentary organic matter and adsorption of DIP onto iron (Fe) oxides. The decomposition rate of sedimentary organic matter rose exponentially with bottom water dissolved oxygen (DO) concentration multiplied by the amplification factor of sediment surface area (ξ), a variable used to describe the intensity of bio-irrigation and physical reworking in the sediment deposit. In the summer of 2020, the Yangtze River catchment encountered the largest flood event in the past 20 years. As a result of enhanced physical reworking of the seabed, dissolved inorganic carbon (DIC) flux increased by approximately 4-fold as compared to the summer of 2019 (657 vs. 154 mmol m−2 d−1). DIP flux exhibited similar inter-annual variations to DIC flux, indicating that changes in the decomposition rate of sedimentary organic matter were the main cause of the inter-annual differences in DIP flux (1.5 mmol m−2 d−1 in 2020 vs. 0.3 mmol m−2 d−1 in 2019). On the other hand, benthic dissolved Fe fluxes declined exponentially with rising DO concentration because of re-oxidation of Fe2+ in porewater into Fe oxides. As a consequence, approximately 90% of DIP sourced from the decomposition of sedimentary organic matter was retained within the sediment when the bottom water was well oxygenated (DO >125 μmol l−1). Our results imply that regeneration of sedimentary P and Fe may be efficient only within a very narrow redox window where DO concentrations are below a threshold value of ∼60 μmol l−1, but bio-irrigation or physical reworking is still active.

Selective organic dye adsorption properties of aluminum oxide cluster

Selective organic dye adsorption properties of aluminum oxide cluster

Adsorption behaviors of organic molecules on Nb/Zr–modified bismuthene: A first–principles study

In this work, the geometric and electronic properties of the adsorption of volatile organic molecules (VOCs) such as CH2O, C2H4O, C2H6O on bismuthene monolayer with transition metal (TM = Nb, Zr) atoms adsorbed are investigated by using first–principles methods, aiming to explore the potential applications of TM–modified bismuthene monolayer in the field of organic molecular gas sensors. In contrast to the adsorption of organic molecules on Zr–bismuthene, Nb–bismuthene appears the chemisorption with multiple organic molecules, and it can be found that Nb–bismuthene could stably adsorb target molecules and exhibit outstanding charge transfer. The longer desorption time of organic molecules on Nb–bismuthene and the higher organic molecular adsorption capacity of the substrate at most temperatures, which suggests that Nb–bismuthene is suitable as a disposable sorbent for organic molecules, providing a viable direction for the application of Nb–bismuthene monolayer as a sensitive material for the removal of organic molecules.

Sunlight assisted highly efficient desorption of ammonia by redox graphene hybrid metal–organic framework photothermal conversion adsorbents

The capture, storage and release of NH3 play a pivotal role in sustainable energy applications. However, to simultaneously achieve high adsorption capacity and low energy desorption remains a challenge. In this work, a novel class of hybrid materials with photothermal conversion performance have been developed by doping redox graphene and metal–organic framework of MOF-303(Al). It is found that the optimized rGO@MOF-303(Al)-8% exhibits high NH3 uptake (17.0 mmol g−1) at 25.0 °C and 1.0 bar and exceptional photothermal conversion performance. Under the irradiation of simulated sunlight, its temperature can be raised to about 75 °C in 10 min. Even under direct natural sunlight irradiation, a stable equilibrium temperature of 53 °C may be achieved. Based on this excellent photothermal conversion performance, we investigated the desorption behavior of ammonia under visible light irradiation for the first time. We found that due to the breakdown of hydrogen bonds of NH3 and N-N, N–H sites of rGO@MOF-303(Al)-8% caused by the rapid rise of temperature, approximately 68% of NH3 could be effectively desorbed in 2-hour irradiation under ambient conditions. In addition, the optimized adsorbent demonstrated remarkable cycling stability. After undergoing 10 cycles, high adsorption capacity and efficient light-induced desorption of NH3 were still maintained Thus, the present study provides a novel concept for high-capacity adsorption and low-energy desorption of NH3 and other industrial gases.

Adsorption of Organic Pollutants on Carbonaceous Adsorbents Prepared by Direct Activation of Sweet Cherry Stones.

The main objective of this study was to assess the usefulness of the sweet cherry stones for the production of carbonaceous adsorbents by means of direct physical activation method, using conventional and microwave variant of heating. The adsorbents were characterized in terms of textural parameters, acidic-basic character of the surface, electrokinetic properties and their suitability for drinking water purification. Adsorption tests were carried out against three organic compounds - Triton X-100 (surfactant), bovine serum albumin (protein) and methylene blue (synthetic dye). Depending on the variant of heating applied during activation procedure, the obtained activated biochars differed significantly in terms of the elemental composition, acidic-basic properties as well as degree of specific surface development and the type of porous structure generated. Adsorption tests have showed that the efficiency of organic pollutants removal from aqueous solutions depends significantly not only on the type of the adsorbent and adsorbate applied, but also on the temperature and pH of the system. The sample prepared by microwave-assisted direct activation proved to be very effective in terms of all tested organic pollutants adsorption. The maximum sorption capacity toward Triton X-100, bovine serum albumin and methylene blue reached the level of 86.5, 23.4 and 81.1 mg/g, respectively.