Equilibrium Capacity Research Articles

Recovery of mixture of hydroxyethylammonium carboxylate protic ionic liquids from sugarcane pretreatment liquor using activated carbon in a fixed bed column

Integrated strategies using fixed bed columns can facilitate the recovery of protic ionic liquids (PILs) used in the pretreatment of lignocellulosic biomass. In this study, we investigated the adsorption of 2-hydroxyethylammonium acetate [Mea][Ac] and 2-hydroxyethylammonium hexanoate [Mea][Hex] on activated carbon in a fixed bed column for recovering the PILs mixture present in the liquor of the pretreatment. Breakthrough curves were determined experimentally. Breakthrough time (tb), exhaustion time (te), difference between tb and te, adsorption efficiency (ϕads), column efficiency (ϕcol) and qe equilibrium capacity were evaluated as a function of simultaneous variations in superficial velocity (vs) and temperature (T) using a central composite rotatable design. The optimum conditions for PIL purification were vs = 1.66 cm/min (Q = 1.3 mL/min) and T = 20 °C. After selection of optimum operating conditions, PILs separation was evaluated in a model solution and sugarcane pretreatment liquor, with similar intervals for recover of PILs. This is the first study to develop a successful proof of concept of mixture PILs [Mea][Ac]/[Mea][Hex] recovery from sugarcane straw pretreatment liquor in a fixed-bed column of activated carbon. The results indicate that the method has great potential for industrial application.

Hollow polyphosphazene microcapsule with rigid-flexible coupling cationic skeletons for highly efficient and selective adsorption of anionic dyes from water

An amino-rich hollow polyphosphazene microcapsule with rigid-flexible coupling cationic skeleton (HTCM) was facilely prepared by one-step polycondensation from hexachlorocyclotriphosphazene and tetraethylenepentamine. The systematic adsorption studies for six single dye systems and three binary mixed dye systems showed that HTCM possessed a highly-efficient and selective adsorption behavior towards anionic dyes from water. Especially, the adsorption capacity of HTCM towards methyl orange (MO) at equilibrium reached 1009.66 mg g−1 at 25 °C, and the relative separation factors of anionic dye MO for three cationic dyes (methylene blue, Crystal violet and Rhodamine B) was up to 124.22, 124.87 and 136.35, respectively. The adsorption rate of MO onto HTCM was very rapid, attaining 68.6 % of adsorption equilibrium capacity for MO within the first 30 min. The adsorption kinetics, isotherm and thermodynamic analysis revealed that the uptake behavior of HTCM towards MO obeyed pseudo-second-order kinetic model, intraparticle diffusion model and Langmuir model, and the uptake process was spontaneous and endothermic. As verified from FT-IR and XPS analysis for HTCM before and after MO adsorption, the adsorption mechanism of HTCM for MO involved electrostatic interaction and hydrogen bonding. The present study promises the potential of HTCM for highly selective separation of anionic dyes from wastewater.

Role of immobilised Chlorophyta algae in form of calcium alginate beads for the removal of phenol: isotherm, kinetic and thermodynamic study

In this work, sodium alginate-immobilised Chlorophyta algae were evaluated for phenol uptake. The algae/alginate bead (AAB) characteristics were analysed by means of BET-BJH, FTIR, and SEM-EDX methods, while the adsorption performance of AABs with respect to phenol removal was investigated using batch studies. The parameters found to affect the biosorption capacity of AABs included pH, contact time, initial phenol concentration, adsorbent dosage, stirring rate, particle size, and temperature, with the optimal operating variables identified as a pH of 6, an initial phenol concentration of 50 mg/L, AAB dosage of 5 g/L, and a 200 rpm stirring rate. The adsorption process in such cases reached equilibrium within 120 min, demonstrating a maximum phenol elimination capacity of 9.56 mg/g at 30 °C. The isotherm and kinetic models used to determine this were evaluated using the Chi-square test (X2), the coefficient of determination (R2), and the value of equilibrium capacity, with results that revealed that the Freundlich isotherm provides the best fit for the relevant equilibrium data, as shown by its high R2 value (0.96) and low X2 value (1.16135); the theoretical data produced by that model were thus closer to the experimental data than that from the Langmuir model. Kinetic analysis showed that the phenol adsorption followed a pseudo-second-order kinetic model. The thermodynamic parameters were thus explored, revealing that the phenol biosorption process is based on spontaneous physisorption with an exothermic reaction due to negative (ΔG°) and (ΔH°) values. The low cost, natural origin, biodegradability, and eco-friendliness of algae/alginate bead sorbents also make them ideally suited for phenol removal in aqueous solutions.

Preparation of hierarchically porous PVP/ZIF-8 in supercritical CO2 by PVP-induced defect-formation method for high-efficiency gas adsorption

The fabrication of structural stable metal organic frameworks (MOFs) with large pore size by facile, rapid and environmentally friendly synthetic method remains a serious challenge. Herein, it is the first time to develop a novel synthetic strategy that rapidly enlarges the pore size of microporous ZIF-8 by employing polyvinyl pyrrolidone (PVP) as a modulator to induce defect formation in environmentally friendly supercritical CO2 (scCO2). Notably, the high solubility and low mass transfer resistance of reactants in scCO2 and low surface tension nature of scCO2 are the key factors for the rapid preparation of structural stable PVP/ZIF-8 with hierarchically pores. And the PVP modulator as a weak ligand not only facilitates pore size but also perturbs coordination to form coordination defects, exposing more coordination metal sites. These characteristics are beneficial to fast diffusion and adsorption of CO2 molecules. In addition, the influences of reaction conditions on the morphology, pore parameter and CO2 adsorption performance of PVP/ZIF-8 are investigated. The result indicates that the PVP/ZIF-8 prepared with 1:1 of Zn/PVP mass ratio at 90 °C and 30 MPa in supercritical environment have the highest CO2 adsorption equilibrium capacity (2.02 mmol CO2/g sorbent) and great cycle stability, which should be attributed to hierarchically porous structure with interconnected macropores and micropores.

Novel Zr-Doped Thiostannate Spinning Fiber (Fiber-KZrTS) for Highly Efficient and Renewable Recovery of Cesium and Strontium from Geothermal Water.

The efficient and renewable recovery of cesium and strontium by absorption from a new type of geothermal water liquid mineral resource is highly desirable but still challenging. In this work, a new Zr-doped layered potassium thiostannate adsorbent (KZrTS) was first synthesized and used for Cs+ and Sr2+ green and efficient adsorption. It was found that KZrTS had very fast adsorption kinetics toward both Cs+ and Sr2+ with an equilibrium reached within 1 min, and the theoretical maximum adsorption capacities for Cs+ and Sr2+ were 402.84 and 84.88 mg/g, respectively. Moreover, to solve the loss problem of the engineering application of the powdered adsorbent KZrTS, KZrTS was uniformly coated with polysulfone by wet spinning technology to form micrometer-level filament-like absorbents (Fiber-KZrTS), whose adsorption equilibrium rates and capacities toward Cs+ and Sr2+ are almost the same as that of powder. Furthermore, Fiber-KZrTS showed excellent reusability, and the adsorption performance remained virtually unchanged after 20 cycles. Therefore, Fiber-KZrTS has potential application for green and efficient cesium and strontium recovery from geothermal water.

The Application of Hydroxyapatite NPs for Adsorption Antibiotic from Aqueous Solutions: Kinetic, Thermodynamic, and Isotherm Studies

Antibiotic pollution has become a serious concern due to the extensive use of antibiotics, their resistance to removal, and their detrimental effects on aquatic habitats and humans. Hence, developing an efficient antibiotic removal process for aqueous solutions has become vital. Amoxicillin (Amox) is one of the antibiotics that has been efficiently removed from an aqueous solution using hydroxyapatite nanoparticles (HAP NPs). The current study synthesizes and utilizes hydroxyapatite nanoparticles as a cost-effective adsorbent. Adsorbent dose, pH solution, initial Amox concentration, equilibrium time, and temperature are among the factors that have an evident impact on Amox antibiotic adsorption. The (200) mg dose, pH (5), temperature (25) °C, and time (120) min are shown to be the best-optimized values. The nonlinear Langmuir’s isotherm and pseudo-second-order kinetic models with equilibrium capacities of 4.01 mg/g are highly compatible with the experimental adsorption data. The experimental parameters of the thermodynamic analysis show that the Amox antibiotic adsorption onto HAP NPs powder is spontaneous and exothermic.

Hybrid salt-enriched micro-sorbents for atmospheric water sorption

Water shortage severely impacts drought-stricken regions, with estimates indicating that almost half a billion people are affected yearly. Composites of Salt and Porous Matrix (CSPMs) are promising functional materials for water vapor sorption. Here, CSPMs were synthesized by loading SAPO-34 porous crystals with highly hygroscopic salts, namely LiCl and CaCl2, individually (mono-salt systems) or combined (binary salt systems) to enhance water sorption capacity and cyclability. The LiCl and CaCl2 content in the impregnation solution impacted the sorption behavior and equilibrium capacity of the resulting composites. Physicochemical, morphological, textural, and sorption properties were evaluated showing that the confinement of binary salts yielded the highest water uptake (0.88 gw/gads at 25 °C and 90 % RH), which was four times higher than that of the parent SAPO-34. The shape of the obtained water vapor isotherms revealed that the salts introduced into the porous structure led to significant changes in the sorption mechanism, with SAPO-34 following a Langmuir behavior (type I isotherm) and the composites a type II isotherm with associated multilayer formation due to the presence of the salts. Kinetic studies also revealed that the materials follow a PSO model dominated by water-surface interactions. Embedding different salts into the same hosting pores to support atmospheric water harvesting was therefore found to enhance capacity and cyclability compared to single inorganic porous structures toward more efficient water sorption processes.

Acrylate-functionalized hyper-cross-linked polymers: Effect of the porogens in the polymerization on their porosity and adsorption from aqueous solution

The porogens are the key components in the polymerization process, they do not participate in the polymerization reaction, but play a very important role in the pore structure of the synthetic polymers. Herein, o-xylene and paraffin were applied as the porogens and three acrylate-functionalized hyper-cross-linked polymers were fabricated according to the suspension polymerization and Friedel-Crafts reaction. The Brunauer-Emmett-Teller (BET) surface area (SBET) and pore volume (Vtotal) of the initial copolymers were nearly zero, while the Friedel-Crafts reaction resulted in a steep increase of the SBET and Vtotal. In particular, the resultant polymer, namely, HCP-PDVE-(Xy), using o-xylene as the porogen had the greatest SBET and Vtotal (1126 m2/g and 0.958 cm3/g, respectively), while the SBET and Vtotal of HCP-PDVE-(Lp) using paraffin as the porogen were the lowest (487 m2/g and 0.299 cm3/g, respectively). Meanwhile, HCP-PDVE-(Xy + Lp) using 50 % of o-xylene and 50 % of paraffin as the mixed porogens possessed the intermediate data. More importantly, HCP-PDVE-(Xy) had the hierarchical micro- and meso-porous distribution, while predominant micro-pores were distributed for HCP-PDVE-(Lp) and HCP-PDVE-(Xy + Lp). The equilibrium adsorption indicated that HCP-PDVE-(Xy + Lp) exhibited the largest equilibrium capacity (qe) to phenol while HCP-PDVE-(Xy) owned the largest qe to Rhodamine B. The phenol adsorption was subjected to the micro-pore filling mechanism while the high SBET, Vtotal and the hierarchical micro-/meso-pores were favorable for the adsorption of Rhodamine B. The kinetic adsorption revealed that HCP-PDVE-(Lp) and HCP-PDVE-(Xy + Lp) (20 min) required much less time than HCP-PDVE-(Xy) (50 min) to reach the equilibrium for the phenol adsorption, and the micro-pore diffusion model characterized the kinetic data very well. The dynamic adsorption indicated that the dynamic capacity of phenol adsorbed on HCP-PDVE-(Xy + Lp) was 160.2 mg/g, very close to the qe (163.6 mg/g) in the equilibrium adsorption.

Breakthrough analysis for parameter estimation of CO2 adsorption on pelletized flexible metal–organic framework

Pellets of elastic layer-structured metal–organic framework-11 (ELM-11), one of the flexible metal–organic frameworks (MOFs), were prepared by mixing ELM-11 powder with a cellulose binder, and the CO2 adsorption behavior of ELM-11 pellets in a fixed-bed adsorber was analyzed to estimate equilibrium and kinetic parameters. Adsorption breakthrough tests were performed under various conditions for the simulated flue gas (20 % CO2–80 % N2) of a blast furnace gas in addition to CO2 isotherm measurements. Experimental CO2 adsorption isotherms on ELM-11 followed a weighted dual-site Langmuir equilibrium model well. The breakthrough analysis results by numerical calculation using the equilibrium model suggested that the gate-opening pressure of ELM-11 shifted to a lower pressure through repeated breakthrough tests. The CO2 adsorption kinetics on ELM-11 pellets agreed well with the linear-driving-force model. Furthermore, CO2 adsorption behavior under various conditions was described well by a mathematical model using a constant value of the mass transfer coefficient under the condition of this study, which was validated against additional experimental data. In addition, it was found that the mass transfer becomes slow under certain conditions that the driving force of the phase transition of ELM-11 is smaller than a threshold, where the amount of CO2 adsorbed on the breakthrough tests did not reach the equilibrium capacity of CO2, which may because the rate-limiting step may be dependent on the CO2 partial pressure and temperature.

A study of kinetic air separation at low temperatures: Oxygen, nitrogen, and argon in carbon molecular sieve

Carbon molecular sieves (CMS) are among the most promising materials for industrial gas separations, including their utilization for the kinetical removal of O2 from N2 and Ar in commercial pressure swing adsorption processes. However, little is known about the characteristics of these kinetics processes at lower temperatures. In this article, a kinetic study was carried out at three temperatures (-25, 0, and 25 °C) for pure O2, N2, and Ar using a commercially available Shirasagi MSC-3K-172. A pressure-swing frequency response technique was applied to determine the dominating mass transfer resistances, as well as corresponding temperature dependences, revealing that a combined resistance model of surface barrier and micropore diffusion best describes the behavior of all three gases. In addition, this MSC-3K-172 exhibited higher kinetic rates but lower kinetic selectivities as compared to Shirasagi MSC-3R-162 and −170, which showed only surface barrier resistances for N2 and Ar. When the temperature was reduced from 25 °C to −25 °C, the equilibrium capacities for three gases increase similarly, but the kinetic rates decrease to varying extents, resulting in an unexpected increase in kinetic selectivity – the value near doubled (from 17 to 33) for O2/N2 and more than tripled (from 24 to 88) for O2/Ar. The observed kinetic selectivities were found to correlate well with the difference of the activation energies between the gas pairs. These activation energies are 36, 29, and 21 kJ/mol for Ar, N2, and O2, respectively, greater than the isosteric heats of adsorption, which follow the reverse order. Together, these results indicate a delicate balance among kinetic selectivities, controlling mass transfer resistances and rate parameters, and equilibrium capacities, and can be utilized for the design of kinetic separations with CMSs, especially when extended to sub-ambient temperatures.

Study on Adsorption of Ag+ by Waste Tea: Adsorption Kinetics, Thermodynamics, Isotherm Properties

Aims: In order to explore the adsorption effect of tea on heavy metal ions in industrial wastewater, Ag+ is used as the research object in this paper. Background: In recent years, heavy metal pollution in water has seriously affected human health and the stability of the ecological environment. In order to reduce the harmfulness of heavy metals, various countries have issued a variety of control standards for heavy metals in water, but there are still great restrictions in the prevention and control technology and level of heavy metal pollution. Therefore, how to effectively treat heavy metal pollution in water has become a hot topic in the field of water pollution management. Objective: The optimized conditions of the adsorption are obtained. Properties of the thermodynamics, adsorption kinetics, and adsorption isotherm are obtained. Methods: In order to determine the best adsorption conditions for Ag+, the influence of factors such as pH value, initial concentration of Ag+, tea dosage, contact time, and adsorption temperature on the adsorption effect of tea is studied. The thermodynamics, adsorption kinetics, and adsorption isotherm are studied. Results: The results showed that when the temperature is 25°C, the pH of the solution was 3.5, the amount of adsorbent was 2.5 g/L, the initial concentration of Ag+ was 125 μg/L and the contact time was 30min, the adsorption rate was highest, reaching 98.11%. The thermodynamic study of adsorption showed that at room temperature and above (298.15-318.15 K), ΔG° < 0, indicating that the adsorption process can be spontaneous. The value of ΔGo in this study is between -20 and -80 kJ/mol, indicating that this is a physicochemical adsorption process. ΔHo = -80.111 kJ/mol < 0, indicating that the adsorption process of Ag+ is exothermic. ΔSo = -188.977 J/(mol·K) < 0, indicating that the adsorption is a process of entropy reduction. The adsorption kinetics study showed that the adsorption equilibrium capacity of different concentrations had a large gap with the experimental results, and the correlation coefficient was small by fitting the quasi-first-order kinetic equation and combining it with the experimental measurements. When the quasi-second-order kinetic equation was used, the calculated values of the equilibrium adsorption capacity of each concentration were basically close to the experimentally measured values, and the correlation coefficient was large, so the kinetics of the adsorption system of Ag+ by tea conformed to the quasi-second-order kinetic equation. The adsorption isotherm of this adsorption process is accorded with the Freundlich model and belonged to heterogeneous adsorption. Conclusion: Tea is a good adsorbent and has the potential for adsorption of Ag+.

Thermodynamic Investigation and Study of Kinetics and Mass Transfer Mechanisms of Oily Wastewater Adsorption on UIO-66–MnFe2O4 as a Metal–Organic Framework (MOF)

Hitherto, a considerable amount of research has been carried out to investigate the equilibrium condition of adsorption process; nevertheless, there is no comprehensive study to evaluate the surface adsorption properties of MOFs. Therefore, the adsorption mechanism and equilibrium capacity of MOFs have not been fully understood. Furthermore, the mass transfer mechanism is still unknown and so it is not possible to predict the adsorption process using MOFs. In this work, a new metal–organic framework (MOF) named UIO-66–MnFe2O4 was synthesized as an adsorbent for oily wastewater treatment. In this way the effects of temperature, amount of adsorbent, adsorption time, pH, and pollutant initial concentration were studied in the treatment of oily wastewater using the UIO-66-MnFe2O4 MOF through the adsorption process. Furthermore, to examine the process of surface adsorption, different adsorption kinetic models (pseudo-first-order, pseudo-second-order, and Elovich) have been performed for the removal of oily pollutants on MOF adsorbents and the surface adsorption mechanism has been discussed carefully. Moreover, to investigate the mass transfer mechanism of oily pollutants in the surface adsorption process, different mass transfer models (Weber and Morris, liquid film diffusion, and Bangham and Burt) have been investigated on porous adsorbents, and finally the mass transfer mechanism of the adsorption process has been proposed.

Nitrogen-rich hierarchical porous polyphosphazene for rapid and efficient adsorption of anionic contaminants: Kinetics, isotherm, thermodynamics and mechanism

The rapid and highly-efficient uptake of waterbody contaminants by polymer-based adsorbent is still a challenge. Herein, a new nitrogen-rich hierarchical porous polymer (PCPM) was synthesized via a self-catalyzed polycondensation between hexachlorocyclotriphosphazene and melamine. The PCPM possessed hierarchical pore architecture with specific surface area of 321.1 m2/g and pore size distribution from 1.3 to 63.0 nm. Owing to the remarkable porous texture and nitrogen-rich active sites with high electron density, PCPM exhibited a high adsorption capacity of 187.5, 336.2, and 320.4 mg g−1 for Cr (VI), Congo red (CR), and diclofenac sodium (DCF), respectively. Moreover, the adsorption rate of these contaminants onto PCPM was very fast, reaching 90 % of adsorption equilibrium capacity for Cr (VI), CR and DCF within the first 7 min, 45 min and 30 min, respectively. Adsorption data revealed that the adsorption process conformed to pseudo-second-order kinetics and Langmuir isotherm model. The removal process was spontaneous, exothermic for Cr (VI) and endothermic for CR and DCF. FT-IR and XPS analysis demonstrated that electrostatic interaction and hydrogen bonding contributed to the adsorption of CR and DCF onto PCPM, while the removal mechanism of Cr (VI) by PCPM included redox reaction and chelation besides the above two interactions.

Robust game-theoretic optimization for energy management in community-based energy system

• A system scheme is proposed to optimize the ESS capacity and energy consumption for multi-community in an individual-oriented way considering the uncertainty of distributed generation. • A robust non-cooperative game approach is formulated for the proposed system scheme, oriented from the pursuit of the economical operation facing with the uncertainty. • To solve the optimization problem, the distributed algorithm is proposed by combining PSO and C&CG algorithm, which can converge to the robust Nash equilibrium. It is significant to schedule energy consumption in community-based energy system consisting of distributed generation, energy storage, multi-community. In this paper, a robust game-theoretic approach is proposed to optimize the storage capacity and energy consumption considering the uncertainty of distributed generation. Energy management with energy storage optimization is studied by considering the cost of distributed generations, cost of energy storage, and bidirectional energy trading. In order to search the robust solution for Nash equilibrium and optimal storage capacity, a distributed algorithm combining column and constraint generation and particle swarm optimization is designed. Simulation results show that the proposed approach has a well performance in reducing operation cost of energy system and tackling the uncertainty of distributed generation.

Effect of sulfur dioxide on adsorption capacity of zeolite sorbents for carbon dioxide

The article discusses a rather serious problem limit-ing the use of adsorption for the CO2 capture from flue gas, in the presence of sulfur dioxide. An apparatus with a vertical batch adsorber was constructed to study adsorption under elevated pressure in a wide range of temperatures and evaluation of CO2 breakthrough curves with an infrared analyzer. The article summarizes the results of experiments conducted with zeolite clinoptilolite, which represented natural materials, and molecular sieve 13X as a representative of synthetic sorbents. Adsorption capacities achieved during cyclically repeated tests with a model gaseous mixture free of SO2 and a mixture of the same composition but enriched with a low volume fraction of SO2 (0.3 %) were compared. Adsorption took place at a temperature of 20 °C and at two overpressures (200 and 500 kPa) of the gas with a 13 % volume fraction of CO2. Each sub-experiment consisted of five adsorption and desorption cycles, where desorption was based on depressurization followed by temperature increase to 120 °C under nitrogen atmosphere. There were no changes in capacities when tested with the gaseous mixture without SO2. Relative to the weight of the sample, the 13X sample at an overpressure of 500 kPa had a capacity of 11.3 % and clinoptilolite 3.8 %. Tests in the presence of SO2 led to a permanent reduction of the equilibrium capacities for both samples and at both pressures. At the overpressure of 500 kPa, the capacity decreased to 7.4 % for the 13X and to 2.5 % for the clinoptilolite. A more intensive desorption involving a thermal and vacuum step did not lead to any improvement for the 13X sample. In contrast, the effect for clinoptilolite was very positive. Its capacity in the fifth cycle reached 3.4 % close to the state without SO2 exposition. In the case when SO2 in the gas was accompanied with 40 % relative humidity, vacuum desorption did not lead to positive results in any case. After five cycles, the capacity of 13X dropped to 3.2 % and clinoptilolite to 1.4 %. When moisture, SO2 and the presence of O2 (volume fraction of 6 %) in the model mixture were further combined, the capacity of 13X decreased to 1.4 % and clinoptilolite to 0.4 % after five cycles. Tests with SO2 (dry gas) caused a decrease in the specific surface area from 512 to 211 m2.g‒1 for the 13X sample. On the other hand, for clinoptilolite it decreased from only 29 to 28 m2.g‒1 under the same conditions. Ac-cording to XRF, it was not possible to remove sorbed SO2 from the 13X sample even by evacuation followed by heating up to 200 °C. Using the XRD method, it was found that SO2 remains in the matrix, although it does not undergo transition to the crystalline phase. The study verified that synthetic molecular sieve 13X, unlike natural clinoptilolite, is not applicable for CO2 adsorption from SO2 containing flue gas.

Activated carbon paper as ethylene adsorber

Abstract The use of activated carbon with KMnO4 activators incorporated on the paper matrix is carried out in this research. Three methods of activated carbon incorporation on paper are carried out to evaluate the paper’s physical parameters and adsorption ability to ethylene. The paper’s physical parameters include grammage, bursting strength, Ring Crush Test (RCT), moisture content, water absorption (Cobb60), and paper microstructures using SEM. Evaluation of the performance of activated carbon paper nanopores as ethylene adsorbent is conducted using GC. The treatment of activated carbon nanopores on non-wood paper causes grammage to increase, but RCT and paper bursting strength decrease. The incorporation of nanopore-activated carbon by the mixing method has produced papers with activated carbon particles spread evenly inside the pulp fibers of the paper. Activated carbon paper with the best adsorption capacity is bamboo+KMnO4&mixing with an adsorption capacity of 1,348 ppm and ethylene amount of 88.58 %. Concentration equilibrium is reached in the 25th minute. The non-linear pseudo-first-order absorbent kinetics model is an appropriate model to describe the equilibrium capacity of ethylene entrant (qe) by nanopore-activated carbon paper with the equation: qt = 1.35734 ( 1 − exp − 0.15312 t ) \mathrm{qt}=1.35734\hspace{0.1667em}(1-{\exp ^{-0.15312\hspace{0.1667em}\mathrm{t}}}) , with R 2 = 0.9981 {\mathrm{R}^{2}}=0.9981 .

Removal of Heavy Metal Ions from Wastewater with Poly-ε-Caprolactone-Reinforced Chitosan Composite.

Currently, the requirements for adsorbent materials are based on their environmentally friendly production and biodegradability. However, they are also related to the design of materials to sustain many cycles in pursuit of low cost and profitable devices for water treatments. In this regard, a chitosan reinforced with poly-ε-caprolactone thermoplastic composite was prepared and characterized by scanning electron microscopy; Fourier transforms infrared spectroscopy, X-ray diffraction analysis, mechanical properties, as well as erosion and swelling assays. The isotherm and kinetic data were fitted with Freundlich and pseudo-second-order models, respectively. The adsorption equilibrium capacities at pH 6 of Zn(II), Cu(II), Fe(II), and Al(III) were 165.59 ± 3.41 mg/g, 3.91 ± 0.02 mg/g, 10.72 ± 0.11 mg/g, and 1.99 ± 0.22 mg/g, respectively. The adsorbent material lost approximately 6% of the initial mass in the adsorption-desorption processes.

Cr-N bridged MIL-101@tubular calcined N-doped polymer enhanced adsorption of vaporous toluene under high humidity

High capacity adsorption of volatile organic compounds (VOCs) in high humidity environment is a crux but challenge for atmospheric VOCs governance. In this work, tubular carbonized N-doped polymers (TCNP) were implanted into MIL-101 via N-Cr-O interface self-assembly, enabling high adsorption for vapor toluene in high humidity. Through mechanical ball milling and carbonization, Cr ions were preloaded on TCNP to form highly dispersed 3–5 nm Cr-N crystallite as anchors for growing MIL-101(Cr/Cu). Newly constructed smaller micropores of 6.8 Å with aromatic rings/N sites at the interface and doped Cu ions in MOF framework synergistically enhanced π-π conjugation and electrostatic interaction for C7H8 molecules. This endowed [TCNP5/MIL(Cr/Cu)]N-Cr 2.9 times higher toluene uptake (6.34 mmol/g) at low vapor pressure (P/P0 = 0.02) and 1.9 times diffusivity under high humidity (60% RH) than that of MIL-101(Cr) at 298 K. The adsorption breakthrough curves for vaporous toluene showed that TCNP@MIL-101(Cr/Cu) exhibited outstandingly higher adsorption equilibrium capacity (2.7 mmol/g) under 80% RH, corresponding to approximately 2–10 times than those of reported state-of-the-art adsorbents under similar conditions. This study provided a novel interface construction strategy for hydrophobic MOF composites, which supplied deeper understanding for VOCs adsorption and promoted MOFs practical application in VOCs capture under humid environment.

Wholesale electricity market economics of solar generation in Israel

We use a two-stage model to determine the equilibrium capacities, generation levels, and prices of a wholesale electricity market in which independent power producers (IPPs) use natural gas-fired (NG) and photovoltaic (PV) technologies. PV's effective capacity is high during midday but low in other daytime hours. Applied to Israel's stylized electricity market in 2030, our model finds NG and PV are necessary to meet Israel's electricity demands; NG mitigates daytime price spikes and enhances consumer welfare; NG IPPs are profitable; and PV IPPs may be unprofitable, potentially requiring government support to aid Israel's achievement of a clean and sustainable future.

Construction of hierarchical porous carbon with mesopores-enriched from sodium lignosulfonate by dual template strategy and their diversified applications for CO2 capture, radioactive iodine adsorption, and RhB removal

Lignosulfonate, as the large-scale by-products from the sulfite pulping, converting them to porous carbon is an alternative potential path. However, most sodium lignosulfonate (LS-Na) derived porous carbon all belonged to the dominated microporous carbon materials, and had poor graphitization degree and low heteroatoms content. Here, a series of hierarchically porous carbon with rich and controllable mesopores were firstly prepared from LS-Na by two dual template strategies. These carbon materials showed high Brunauer-Emmett-Teller (BET) surface areas (SBET) of 230.6–1483.3 m2/g, hierarchical porous structure (mesopore content up to 84.5%), rich heteroatoms (N, O, S) doping (9.22–22.53%), and good graphitization structure. The incorporation of SBA-15 and Ni species as the nano-templates not only brought the unique micro-structure, but also enhanced mesoporous properties. SLS-C had the largest CO2 uptake (206.2 mg/g) due to the largest micropore volume (Vmicro) and ultramicropore volume (Vultra) by micropore filling mechanism. SLS-S-Ni-C possessed effective iodine capacity (∼2.2 g/g) and good recycling (∼90.9%), the adsorption process was based on the dominated physical adsorption, meanwhile, also along with the weak chemical interaction for some iodine molecules by little strong binding sites. SLS-Ni-C had the largest equilibrium capacity of RhB (350.6 mg/g) and the fast adsorption kinetic (about 50 min) due to the large SBET, suitable micro-mesopores size and proportion. This work provided a kind of hierarchical porous carbon from LS-Na by dual template routes, and matched adsorbents for the removal of targeted contaminants.