High Adsorption Research Articles

Excellent Adsorption of Lead (II) and Chromium (VI) from Water Using Zwitterions (-NH3+ and -COO-) Functionalized Nano Lanthanum Oxide: Kinetic, Isotherm, Thermodynamic, and Surface Mechanism.

Zwitterion amino acid l-cysteine functionalized lanthanum oxide nanoparticles (l-Cyst-La2O3 NPs) have been synthesized for the first time with lanthanum acetate as the precursor, NH4OH as the base, and l-cysteine as the in situ functionalized mediator. The typical size of l-Cyst-La2O3 NPs was obtained in the range of 15-20 nm from the TEM technique. A cytotoxicity test of l-Cyst-La2O3 NPs was performed in Raw 264.7 cell lines, which were shown to be highly biocompatible. The point zero charge pH (pHPZC) of bare and l-Cyst functionalized La2O3 NPs was obtained at pH 6 and 2. The maximum uptake capacities of l-Cyst-La2O3 NPs at temperatures 25-45 °C were obtained as 137-282 mg/g for Pb2+ and 186-256 mg/g for Cr6+. All of these values are much higher than those reported in the literature with other nanomaterials. The presence of -SH, -NH2, and -COOH functional groups in zwitterion l-cysteine provides multiple binding sites leading to the high adsorption of Pb2+ and Cr6+. Five-cycle desorption studies were successfully performed to regenerate the spent l-Cyst-La2O3 NPs.

Synthesizing hard carbon anodes for potassium-ion batteries from black liquor and deinking sludge

Porous hard carbon anodes, with large interlayer space and high adsorption ability, can offer much better cycle stability and higher discharge capacity for potassium-ion batteries compared to commercial graphite anodes. However, most commercial hard carbons are synthesized from relatively expensive high-molecular polymers. In this study, pulping and papermaking wastes were utilized as precursors for producing hard carbons and pore-enlarging agent, respectively. Specifically, after thorough mixing through ball milling, black liquor solids and deinking sludge were utilized to produce porous hard carbon anodes via co-pyrolysis. The results show that direct pyrolysis of black liquor can produce hard carbons efficiently, eliminating the need to extract lignin from black liquor. Moreover, it is shown that the pore-enlarging agent derived from deinking sludge can enlarge much portion of pores on hard carbons, resulting in abundant mesopores. Electrochemical tests demonstrate that the synthesized porous hard carbon anodes can achieve highest specific capacity of 303.5 mAh g−1 at 100 mA g−1 using a 1.0 M potassium hexafluorophosphate electrolyte in a mixture of diethyl carbonate and ethylene carbonate. Additionally, the synthesized porous hard carbon anodes exhibit low average capacity decay per cycle of 0.06 % at 100 mA g−1 when tested with a 1.0 M potassium bis(fluorosulfonyl)imide electrolyte in the same solvent mixture after 500 cycles. Therefore, recycling black liquor and deinking sludge to produce porous hard carbon anodes for potassium-ion batteries is a promising approach for environmental and energy sustainability.

Amorphous MoS2/MoO3 nanosheets as high‐efficient polysulfide barrier in Li‐S batteries

Lithium‐sulfur batteries (LSBs) are seriously impeded by poor reaction kinetics and the polysulfides shuttling, leading to low utilization of sulfur and poor cycling performance. Herein, amorphous MoS2/MoO3 nanosheets are prepared by a one‐step formamide (FA)‐assisted strategy. Due to the merits of high adsorption capability and good catalytic activity of MoS2, relatively high electronic conductivity and strong polarity of MoO3, and abundant active sites of amorphous nanosheet structure, the LSBs based on amorphous MoS2/MoO3‐2 nanosheets coated separator exhibit an outstanding specific capacity (1420.2 mA h g‐1 at 0.1 C), excellent rate capacity (505.4 mA h g‐1 at 5 C), and long cycle life (a negligible decay rate of 0.063 % per cycle at 0.5 C). This work provides an idea for designing efficient amorphous catalytic materials in LSBs.

Preparation of MOR/P(S‐co‐VPh) nanofiber composite membrane and its adsorption properties for rubidium ions

AbstractRubidium (Rb), a rare and precious metal, is widely used in high‐tech fields. In this work the structural advantages of mordenite (MOR) and group affinity of phenolic hydroxyl polymers (poly (styrene‐4‐hydroxystyrene) (P(S‐co‐VPh)) are combined to prepare MOR/P(S‐co‐VPh) nanofiber composite membranes with high selectivity and adsorption specificity for Rb+ by electrospinning. The test results show that MOR is successfully anchored on the nanofiber substrate and maintained its complete crystal structure. Adsorption experiments show that the adsorption capacity of Rb+ increases with the increase of MOR content, and pH = 9.0, T = 25°C are the best adsorption conditions. K+ shows the most obvious interference with the adsorption capacity decreased from 60.03 to 39.33 mg/g. The adsorption process follows with the Langmuir isothermal model and pseudo‐second‐order kinetic equation. The chemical adsorption based on the coordination reaction is the control step, and the intraparticle diffusion also has an important effect on the adsorption rate. The recycling test indicates that the prepared nanofiber composite membrane not only has efficient adsorption of Rb+, but also exhibits excellent regeneration and stability, which helps to achieve its widespread application and long‐term operation in harsh environments.

Application and mechanism of carbonate material in the treatment of heavy metal pollution: a review.

Among the many heavy metal pollution treatment agents, carbonate materials show strong flexibility and versatility by virtue of their high adsorption capacity for heavy metals and the characteristics of multiple and simple modification methods. It shows good potential for development. This review summarizes the application of carbonate materials in the treatment of heavy metal pollution according to the research of other scholars. It mainly relates to the application of surface-modified, activated, and nano-sized carbonate materials in the treatment of heavy metal pollution in water. Natural carbonate minerals and composite carbonate minerals solidify and stabilize heavy metals in soil. Solidification of heavy metals in hazardous waste solids is by MICP. There are four aspects of calcium carbonate oligomers curing heavy metals in fly ash from waste incineration. The mechanism of treating heavy metals by carbonate in different media was discussed. However, in the complex environment where multiple types of pollutants coexist, questions on how to maintain the efficient processing capacity of carbonate materials and how to use MICP to integrate heavy metal fixation and seepage prevention in solid waste base under complex and changeable natural environment deserve our further consideration. In addition, the use of carbonate materials for the purification of trace radioactive wastewater and the safe treatment of trace radioactive solid waste are also worthy of further exploration.

Pretreatment of wastepaper with an aqueous solution of amino acid-derived ionic liquid for biochar production as adsorbent.

The carbonization of lignocellulosic biomass with ionic liquids (ILs) are considered as an advantageous approach for the preparation of carbonaceous materials. The commonly used imidazolium and pyridinium based ILs have drawbacks such as toxicity, resistance to biodegradation, high cost and viscosity. These issues can be mitigated by diluting ILs with water, although excessive water content above 1wt% can reduce the solubility of biomass. This research aims to investigate the potential of pretreating wastepaper with a "fully green" ILs, amino acid-based IL with high water content, followed by pyrolysis without IL, in enhancing the properties of biochar. For this purpose, the paper was treated with an aqueous solution of IL cysteine nitrate ([Cys][NO3]), and the IL was not involved in the pyrolysis process to prevent the formation of secondary gaseous pollutants. The findings revealed that the hemicellulose and mineral filler in the paper were eliminated during pretreatment, leading to higher carbon content but lower oxygen content. As a result, the biochar exhibited micropores of 0.42 cm3g-1 and a specific surface area of 1011.21m2g-1. The biochar demonstrated high adsorption capacities for Cd2+, enrofloxacin, bisphenol A, ciprofloxacin, and tetracycline, with values of 45.20mgg-1, 49.82mgg-1, 49.90mgg-1, 49.88mgg-1, and 49.65mgg-1, respectively. The proposed mechanism for the adsorption of enrofloxacin by the biochar primarily involves physical adsorption such as pore filling and electrostatic interactions, along with chemical adsorption facilitated by graphitic nitrogen.

Production and Characterization of Activated Carbon Derived from Costus Afer Leaves (C. afer) for the Adsorption of Methylene Blue Dye from an Aqueous Solution

In this work, Costus afer leaves (C. after) was utilized as an agricultural waste material for the synthesis of activated carbon (AC) used for the adsorption of methylene blue dye from its aqueous solution. The raw material was prepared, chemically activated using KHCO3 with an impregnation ratio of 1:3, and later carbonized at a temperature of 700℃ in an inert N2 atmosphere for 1hour to produce activated carbon. The proximate analysis of the biomass revealed the percentage of ash content, moisture content, volatile matter, and fixed carbon present in the waste biomass. The raw and activated carbon produced were characterized using various tests such as: Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), Fourier Transform Infrared-(FTIR) Spectrometry, X-Ray Fluorescence (XRF), and Brunauer-Emmett-Teller (BET). The results revealed that the SBET of the biomass increased from 400m2/g to 600m2/g after activation. Adsorption studies were carried out in batch mode to determine the influencing factors of adsorption with varying adsorbent dosage, contact time, and pH values. The adsorption experiment revealed high adsorption efficiency at an optimum parameter of dosage (0.2g), contact time (10 min), and pH (8) with a 70.58% removal of methylene blue dye. An increase in dosage, contact time, and pH above the optimum parameter leads to a decrease in percentage removal. The adsorption capacity was achieved using adsorption isotherm models like Langmuir and Freundlich. Adsorption of methylene blue validated the Langmuir model with an R2 of 0.999 and a Qm of 11.83 mg/g. These results show that activated carbon prepared from Costus afer leaves constitutes an effective low-cost material for the adsorption of Methylene dye from wastewater.

Pilot-scale foam and cast-coated nanocellulose filters for water treatment

AbstractA large variety of substances, for instance heavy metal ions from different sources including mining, industry, and agricultural activities, pollute fresh water sources. Bio-based adsorbents, such as cellulose nanofibers (CNF), have recently been introduced in the process of treating water to remove hazardous pollutants primarily owing to their natural abundance, non-toxicity, and renewability. Surface modification of CNF, e.g. by catalytically oxidising the primary C6-OH groups of CNF selectively into carboxylic (COO−) groups with TEMPO, yields materials that are effective in adsorbing positively charged heavy metal ions, e.g. Cu ions. However, to utilise CNF in continuous processes beyond static, batch-wise adsorption, in particular on (pre-)industrial scale, they need to be immobilised on filter substrates in thin layers and an efficient manner. In this work, we report bio-adsorbent-based filters prepared by coating TEMPO-CNF on viscose filters using two different pilot-scale coating approaches, foam and cast coating. The performance of TEMPO-CNF filters was evaluated in terms of their water permeance as well as adsorption of metal ions including Cu(II) and Ca(II). By foam coating thin layers could be fabricated in a time efficient way facilitating high adsorption capacities (52 mg g−1), whilst by cast coating higher amounts of TEMPO-CNF could be deposited allowing for adsorbing higher absolute amounts (280 mg m−2) of heavy metal ions. Graphical abstract

From scraps to purification: innovative use of food waste-derived hydrochar in eradicating pharmaceutical pollutants.

Chemical products (CPs) such as carbamazepine and naproxen, present in aquatic environments, pose significant risks to both aquatic life and human health. This study investigated the use of hydrothermally carbonized food waste-derived hydrochar (AC-HTC) at three distinct temperatures (200, 250, and 300°C) as an adsorbent to remove these CPs from water. Our research focused on the impact of hydrothermal carbonization temperature on hydrochar properties and the effects of chemical activation with phosphoric acid on adsorption capacity. Hydrothermal carbonization increased the hydrochar's surface area from 1.47 to 7.52 m2/g, which was further enhanced to 32.81 m2/g after activation with phosphoric acid. Batch adsorption experiments revealed that hydrochar produced at 250°C (AC-HTC-250) demonstrated high adsorption capacities of 49.10mg/g for carbamazepine and 14.35mg/g for naproxen, outperforming several conventional adsorbents. Optimal adsorption occurred at pH 4, aligning well with the Langmuir and pseudo-first-order models. The hydrochar showed potential for regeneration and multiple uses, suggesting its applicability in sustainable wastewater treatment. Future research will explore scalability and effectiveness against a broader range of pollutants.

The influence of doping with different surface modified SiO2 nanoparticles on the dielectric properties of natural ester insulating oil

Nanoparticles are presently considered to be high-potential filler materials in insulation medium. Surface-modified nanoparticles can not only improve the compatibility between nanoparticles and insulation liquid but also enhance the dielectric properties. Herein, models of soybean oil-based natural ester insulation oil doped with two silane coupling agents (A151, KH550) modified SiO2 were established, respectively. Molecular dynamics and DFT first principles were applied to explore the effect of two nanoparticles on the dielectric properties of liquid-insulation medium. The results showed that two types of nanoparticles can restrict the diffusion of water molecules by forming hydrogen bonds, while the number of hydrogen bonds in KH550–SiO2 is one-third more than that in A151-SiO2, and the interaction energy is lower, demonstrating a stronger adsorption effect on water molecules. Moreover, surface electrostatic potential and frontier molecular orbitals showed that KH550–SiO2 have a higher adsorption on charged particles in natural ester insulation oil, which can further inhibit the development of streamer discharge in the liquid insulation medium, improve its dielectric property and delay the aging and deterioration of natural ester insulation oil. This study extends our knowledge into the influence of silane coupling agents modified SiO2 nanoparticles on the dielectric performance of liquid insulation materials from a microscopic perspective.

One‐Step Synthesis of Thiol‐Functional Mesoporous Silica Nanospheres and Selective Removal of Cationic Dyes

AbstractThe surface characteristics of nanoparticles have a huge impact on adsorption effects. In this paper, thiol‐functional mesoporous silica nanospheres (MSNs−SH) are successfully prepared through simple one‐step hydrolysis and co‐condensation of tetraethyl orthosilicate and (3‐mercaptopropyl) triethoxysilane with hexadecyltrimethylammonium bromide and sulfobetaine 12 as dual‐template. The obtained MSNs−SH have high surface area (1260 m2 g−1), accessible mesopores (2.2 nm), great pore volume (1.7 cm3 g−1), and uniform adjustable diameter (90 nm). Furthermore, the diameter and pore‐size of MSNs−SH can be controlled via adjusting the ethanol content in the synthesis system. MSNs−SH exhibit a fast adsorption kinetics, marked adsorption capacity of cationic rhodamine B (RB 534.2 mg g−1), and remarkable selective adsorption for cationic dyes. Theoretical analysis reveals the adsorption behavior of RB on MSNs−SH follows the Langmuir isotherm models and pseudo‐second‐order kinetic. Additionally, the thermodynamic results indicate that the adsorption process is a spontaneous process driven by temperature. The results demonstrate that MSNs−SH are greatly potential for effectively removing cationic dyes from wastewater, with the advantages of simple preparation, high adsorption performance and perfect selectivity.

Effect of Physico-Chemical Properties Induced by N, P Co-Doped Biomass Porous Carbon on Nitrous Oxide Adsorption Performance

The adsorption and enrichment of greenhouse gases on biomass porous carbon is a promising approach. Herein, a simple type of nitrogen and phosphorus co-doped biomass porous carbon (NPPC), which was derived from fast-growing eucalyptus bark, was reported via one-step method of carbonization and activation, and the nitrous oxide (N2O) adsorption performance and the adsorption mechanism of the NPPCs were also investigated. The results showed that NPPC-800-2 demonstrated a high specific surface area (1038.48 m2∙g−1), abundant micropores (0.31 cm3∙g−1), and enriched content of N and P (4.17 wt.% and 0.62 wt.%), which also exhibited a high N2O adsorption capacity of 0.839 mmol∙g−1. Moreover, the addition of N enhanced the surface polarity of carbon, thereby altering its pore structure. And P doping induced changes in the structural orientation of carbon, resulting in an increased presence of N-P functional groups. This finding reveals that the eucalyptus bark-based N and P co-doped porous carbon shows great potential for wide applications in N2O capture and provides effective guidance for the design and development of waste biomass adsorbent.

Isomeric Porous Cu(I) Triazolate Frameworks Showing Periodic and Aperiodic Flexibility for Efficient CO Separation.

Guest-induced (crystal-to-crystal) transformation, i.e., periodic flexibility, is a typical feature of molecule-based crystalline porous materials, but its role for adsorptive separation is controversial. On the other hand, aperiodic flexibility is rarely studied. This work reports a pair of isomeric Cu(I) triazolate frameworks, namely, α-[Cu(fetz)] (MAF-2Fa) and β-[Cu(fetz)] (MAF-2Fb), which show typical periodic and aperiodic flexibility for CO chemical adsorption, respectively. Quantitative mixture breakthrough experiments show that, while MAF-2Fa exhibits high adsorption capacity at high pressures but negligible adsorption below the threshold pressure and with leakage concentrations of 3-8%, MAF-2Fb exhibits relatively low adsorption capacity at high pressures but no leakage (residual CO concentration <1 ppb). Tandem connection of MAF-2Fa and MAF-2Fb can combine their advantages of high CO adsorption capacities at high and low pressures, respectively. MAF-2Fa and MAF-2Fb can both keep the separation performances unchanged at high relative humidities, but only MAF-2Fb shows a unique coadsorption behavior at a relative humidity of 82%, which can be used to improve purification performances.

Pore Fractal Characteristics between Marine and Marine–Continental Transitional Black Shales: A Case Study of Niutitang Formation and Longtan Formation

Marine shales from the Niutitang Formation and marine–continental transitional shales from the Longtan Formation are two sets of extremely important hydrocarbon source rocks in South China. In order to quantitatively compare the pore complexity characteristics between marine and marine–continental transitional shales, the shale and kerogen of the Niutitang Formation and the Longtan Formation are taken as our research subjects. Based on organic petrology, geochemistry, and low-temperature gas adsorption analyses, the fractal dimension of their pores is calculated by the Frenkel–Halsey–Hill (FHH) and Sierpinski models, and the influences of total organic carbon (TOC), vitrinite reflectance (Ro), and mineral composition on the pore fractals of the shale and kerogen are discussed. Our results show the following: (1) Marine shale predominantly has wedge-shaped and slit pores, while marine–continental transitional shale has inkpot-shaped and slit pores. (2) Cylindrical pores are common in organic matter of both shale types, with marine shale having a greater gas storage space (CRV) from organic matter pores, while marine–continental transitional shale relies more on inorganic pores, especially interlayer clay mineral pores, for gas storage due to their large specific surface area and high adsorption capacity (CRA). (3) The fractal characteristics of marine and marine–continental transitional shale pores are influenced differently. In marine shale, TOC positively correlates with fractal dimensions, while in marine–continental shale, Ro and clay minerals have a stronger influence. Ro is the primary factor affecting organic matter pore complexity. (4) Our two pore fractal models show that the complexity of the shale in the Longtan Formation surpasses that of the shale in the Niutitang Formation, and type I kerogen has more complex organic matter pores than type III, aiding in evaluating pore connectivity and flow effectiveness in shale reservoirs.

RSM versus ANN for modeling and optimization of magnetic adsorbent based on montmorillonite and CoFe2O4

A highly resourceful, environmentally benign, and recyclable magnetic montmorillonite composite (MMT/CF) was obtained through a simple one-step hydrothermal method and exhibited excellent Pb (II) removal. The as-synthesized adsorbent was then characterized by XRD, SEM–EDX, FTIR, BET, and TGA-DTA. The operating parameters including adsorbent dosage, initial Pb (II) concentration, solution pH, and time were studied. Also, a comparative approach was formed between response surface methodology (RSM) and artificial neural network (ANN) to optimize and model the removal efficiency of Pb (II) by MMT/CF. The results indicated that the ANN model was more precise and quite trusted optimization tool than RSM in consideration of its higher correlation coefficient (R2 = 0.998) and lower prediction errors (RMSE = 0.851 and ADD = 0.505). Langmuir isotherm provided the best fit to the experimental data, and the maximum adsorption capacity was 101.01 mg/g. Additionally, the kinetic studies showed that the pseudo-second-order model fitted well with the experimental data. The magnetic MMT/CF composite possesses high adsorption capacity and is suitable for reuse. Therefore, this study shows that MMT/CF composite can be a potential adsorbent in Pb (II) uptake from aqueous media.

Application of nanoparticles as novel adsorbents in blood purification strategies.

Blood purification therapy for patients overloaded with metabolic toxins or drugs still needs improvement. Blood purification therapies, such as in hemodialysis or peritoneal dialysis can profit from a combined application with nanoparticles. In this review, the published literature is analyzed with respect to nanomaterials that have been customized and functionalized as nano-adsorbents during blood purification therapy. Liposomes possess a distinct combined structure composed of a hydrophobic lipid bilayer and a hydrophilic core. The liposomes which have enzymes in their aqueous core or obtain specific surface modifications of the lipid bilayer can offer appreciated advantages. Preclinical and clinical experiments with such modified liposomes show that they are highly efficient and generally safe. They may serve as indirect and direct adsorption materials both in hemodialysis and peritoneal dialysis treatment for patients with renal or hepatic failure. Apart from dialysis, nanoparticles made of specially designed metal and activated carbon have also been utilized to enhance the removal of solutes during hemoadsorption. Results are a superior adsorption capacity and a good hemocompatibility shown during treatment of patients with toxication or end-stage renal disease. In summary, nanomaterials are promising tools for improving the treatment efficacy of organ failure or toxication. KEY MESSAGES The pH-transmembrane liposomes and enzyme-loaded liposomes are two representatives of liposomes with modified aqueous inner core which have been put into practice in dialysis. Unmodified or physiochemically modified liposomal bilayers are ideal binders for lipophilic protein-bound uremic toxins or cholestatic solutes, thus liposome-supported dialysis could become the next-generation hemodialysis treatment of artificial liver support system. Novel nano-based sorbents featuring large surface area, high adsorption capacity and decent biocompatibility have shown promise in treatment of uremia, hyperbilirubinemia, intoxication, and sepsis. A major challenge of production lies in avoiding changes in physical and chemical properties induced by manufacturing and sterilizing procedures.

Preparation of surface molecularly‐imprinted magnetic kaolin for selective separation and determination of thiabendazole

AbstractIn this study, a selective sorbent was fabricated by combining a surface molecularly‐imprinted polymer and magnetic kaolin for reliable quantification of thiabendazole (TBZ) coupled with spectrofluorimetry. Several surface characterization methods were conducted to confirm the synthesis of TBZ‐imprinted magnetic kaolin with a polymer thickness of ~48 nm. The molecularly‐imprinted magnetic kaolin (MIP@MKLN) showed high adsorption capacity (8.7 mg/g), remarkable selectivity with an imprinting factor of 3.71 and excellent regeneration ability for up to 10 uses without significant change of its initial adsorption capacity for TBZ. The proposed method had linear range from 5 to 500 μg/mL TBZ concentration with a correlation coefficient of 0.995 and the limit of detection was 1.4 μg/mL. MIP@MKLN was used for selective separation and quantification of TBZ in orange and lemon samples. There were high recovery values ranging from 96.4% to 100.2% with lower relative standard deviations (less than 5%) in the spiked samples under optimized conditions. Overall, the proposed method based on MIP@MKLN as an excellent sorbent could produce a feasible, convenient, and promising method for rapid, selective, and sensitive quantification of TBZ in real samples.

One-pot synthesis of novel polyvinylphosphonic acid hydrogels for efficient separation of low-enriched uranium in water

Uranium extraction from seawater and the treatment of radioactive wastewater has traditionally been a hot topic. Herein, p(VPA-AM)n solid hydrogels with high uranium extraction properties based on vinylphosphonic acid (VPA) were successfully prepared by one-step copolymerization for the first time. The batch adsorption experiments demonstrated that p(VPA-AM)n has strong uranium chelating ability, fast uranium adsorption kinetics (within 200 min) and high uranium adsorption capacity (644.67 mg/g), and its adsorption behavior conforms to the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, which is a spontaneous heat-absorbing chemical monolayer adsorption process. After 15 adsorption–desorption tests, the adsorption capacity was kept above 96 % of the original capacity, and the uranium extracted from the salt lake water achieved at 3.56 mg/g, which showed superb behavior in treating complex uranium systems. Mechanism studies revealed that the strong interaction between UO22 + and −PO43- dominated the adsorption and the robust complexation might have led to the electron transfer in the structure. The maximum uranium removal rate of p(VPA-AM)n in simulated seawater reached 90 %, and the simple in situ zinc oxide-modified p(VPA-AM)n hydrogel showed good anti-biosludge properties against three common bacteria (E. coli, B. subtilis and S. aureus), which has a great potential for application in seawater uranium extraction and uranium wastewater treatment.

CO2-Based Stable Porous Metal-Organic Frameworks for CO2 Utilization.

The transformation of carbon dioxide (CO2) into functional materials has garnered considerable worldwide interest. Metal-organic frameworks (MOFs), as a distinctive class of materials, have made great contributions to CO2 capture and conversion. However, facile conversion of CO2 to stable porous MOFs for CO2 utilization remains unexplored. Herein, we present a facile methodology of using CO2 to synthesize stable zirconium-based MOFs. Two zirconium-based MOFs CO2-Zr-DEP and CO2-Zr-DEDP with face-centered cubic topology were obtained via a sequential desilylation-carboxylation-coordination reaction. The MOFs exhibit excellent crystallinity, as verified through powder X-ray diffraction and high-resolution transmission electron microscopy analyses. They also have notable porosity with high surface area (SBET up to 3688 m2 g-1) and good CO2 adsorption capacity (up to 12.5 wt %). The resulting MOFs have abundant alkyne functional moieties, confirmed through 13C cross-polarization/magic angle spinning nuclear magnetic resonance and Fourier transform infrared spectra. Leveraging the catalytic prowess of Ag(I) in diverse CO2-involved reactions, we incorporated Ag(I) into zirconium-based MOFs, capitalizing on their interactions with carbon-carbon π-bonds of alkynes, thereby forming a heterogeneous catalyst. This catalyst demonstrates outstanding efficiency in catalyzing the conversion of CO2 and propargylic alcohols into cyclic carbonates, achieving >99% yield at room temperature and atmospheric pressure conditions. Thus, this work provides a dual CO2 utilization strategy, encompassing the synthesis of CO2-based MOFs (20-24 wt % from CO2) and their subsequent application in CO2 capture and conversion processes. This approach significantly enhances overall CO2 utilization.

REINFORCEMENT OF COMPRESSED STABILIZED EARTH BLOCKS WITH BIOCHAR RESULTING FROM USE OF AGRO-INDUSTRIAL WASTE

ABSTRACT Over the past few decades, the transformation and utilization of materials obtained from agricultural residues as a circular economy strategy have been extensively discussed. Rice husk has received special attention due to the presence of biogenic oxides or biosilica (Gomez-Vazquez et al., 2022; Shafigh et al., 2014; A. B. Souza et al., 2021). This study aimed to evaluate the technical feasibility of using rice husk biochar, a by-product of bioenergy utilization of this agroindustry waste, by developing a multi-factor statistical analysis during the formulation of compressed stabilized earth blocks (CSEB). A central composite experimental design was implemented to examine the contribution of factors such as the percentage of biochar (2.5–17%) and drying temperature (40–100°C) of the CSEB on its mechanical properties. The ANOVA analysis and response surface evaluation demonstrated that biochar up to 14.5% could be added while maintaining a minimum strength of 2MPa. Moreover, the drying temperature significantly affected the mechanical strength of the CSEB, and a complex interaction between clay and biochar was observed, allowing for high mechanical strength and adsorption capacities of the CSEB simultaneously.