Zeolite Pores Research Articles

Adsorption of fluorine from lepidolite hydrometallurgy wastewater by aluminum modified zeolite.

Fluoride contamination is a serious environmental problem in lepidolite hydrometallurgy wastewater. The treatment of fluoride-bearing wastewater is challenging because of the presence of coexisting ions including lithium (Li+), rubidium (Rb+), silicate (SiO32-), sulfate radical (SO42-). However, aluminum-modified zeolite (Al@zeolite) with sufficient hydroxyl groups and high adaptability has unique advantages for eliminating fluoride from lepidolite hydrometallurgy wastewater. Al@zeolite was prepared on natural zeolite by an atmospheric process and then used for the adsorption of fluorine from fluoride-bearing wastewater produced by the lepidolite hydrometallurgy process. The results of material characterization confirmed the successful immobilization of aluminum within the zeolite pores and indicated the formation of zeolite-Al-OH. The zeolite host significantly enhanced the chemical stability of Al@zeolite against pH changes for a wide pH range of 2.0-10.0. The adsorbent had a surface area of 33.46m2/g and demonstrated excellent capacity and selectivity for fluoride adsorption. Notably, a maximum adsorption of 98.6% was observed at a pH value of 6.0 for a duration of 20min with a fluoride content of 20mg/L, and the equilibrium concentration decreased to 0.4mg/L. The results of fluorine adsorption showed that fluoride uptake onto Al@zeolite agreed well with the pseudo-second-order kinetic model and the Langmuir isotherm model. The reusability of the substance was evaluated for up to eight cycles following consecutive regeneration with 0.2mol/L AlCl3. The exhausted Al@zeolite was effectively regenerated through simple alkaline treatment for recycling. The above results verified that Al@zeolite is a new kind of efficient defluoridation adsorbent for lepidolite hydrometallurgy wastewater with practical application prospects.

Experimental and Theoretical Investigation of the Catalytic Activities of Different Zeolites for the Nitration of Toluene.

Zeolites are used in the field of toluene nitrification reactions, but their intrinsic mechanism is not well explained. In this work, three typical zeolites including HZSM-5, HY, and Hβ are selected as catalysts and used for the nitration of toluene and typical monosubstituted benzenes with NO2, and it explores the intrinsic influences on the nitrification of toluene on various zeolites through experimental and theoretical methods. The acidic properties and pore structures of three different zeolites were investigated through appropriate characterization techniques. Hβ zeolite exhibited the highest catalytic performance among the three zeolites, attributable to its unique pore structure and acidic properties. The theoretical analysis of various zeolites indicates that the Hβ zeolite can effectively reduce the activation energy barrier, thereby significantly enhancing the transfer nitration performance. The theoretical calculations also suggest that the para-nitration product is more readily formed within the pores of Hβ zeolite, resulting in high para-selectivity. This study provides a theoretical basis for the selective catalysis of aromatics on zeolites.

Tailoring pores of AFN-related zeolites for enhanced separation of CO2/N2 and CO2/CH4

Zeolites with small-pores (8-ring) are widely used in separation of small-molecule gas, however, the precise tuning of aperture sizes to achieve the ideal selectivity still remains challenge due to their limited topology structures. In this work, SAPO-14 zeolite with AFN topology featuring by different 8-ring windows in three-dimension directions has been synthesized and studied in the separation of CO2/N2 or CO2/CH4. Aiming to further adjust pores and channels of the adsorbents, the composite zeolites of SAPO-14 and SAPO-34 (CHA) are prepared by seed-assisted method, and multi-cycle crystallization is adopted to form the interconnected pores of composites and reduce the crystal size. SAPO-14/SAPO-34 zeolites exhibit the comprehensive performance of high CO2 capacity of SAPO-34 and good selectivity of SAPO-14 due to their appropriate pore structure. At 298 K, the CO2 capacity of S-1 composite is 47.24 cm3 g−1, giving a high gas selectivity for CO2/N2 (68.64) and CO2/CH4 (21.61). The highly-efficiency and good reproducibility in gas separation are verified by the binary breakthrough experiments. The strategy of composite zeolite proposed by this work can effectively regulate the pores of adsorbent, thus endow them acceptable selectivity and capacity for target gas.

Removal of Pb(II), Cr(III), Co(II), Cu(II) cations from aqueous solutions using tetraethylenepentamine-functionalized HY cubic zeolite: optimization, characterization, and mechanistic insights.

This research utilized tetraethylenepentamine-functionalized HY cubic zeolite as an adsorbent to effectively remove heavy metals from aqueous solutions. The adsorbent was characterized using FT-IR, XRD, TGA, FE-SEM, and EDS-MAP techniques. The synthesis aimed to optimize and evaluate the removal efficiency of Pb(II), Cr(III), Co(II), and Cu(II) from aqueous solutions by investigating key parameters, including initial pH, concentration, adsorbent dosage, and contact time. The results indicate that the highest adsorption capacities for each metal follow the order: Pb(II) > Cr(III) > Co(II) > Cu(II), with respective percentages of 99.7%, 98.2%, 95.1%, and 92.4%. Analysis of the batch systems reveals that the equilibrium data for Pb(II), Cr(III), Co(II), and Cu(II) align well with the Langmuir and Freundlich isotherms also show a good fit, with correlation coefficients (R2) higher than 0.9335 and 0.9478, respectively. The maximum adsorption capacities (181.82, 175.44, 169.49, and 158.73mg/g) reflect the nature of the adsorption process. Kinetic studies for Pb(II), Cr(III), Cu(II), and Cu(II) yielded correlation coefficients (R2) higher than 0.9971. These high R2 values suggest that the experimental data closely fit a pseudo-second-order model, indicating a two-step adsorption mechanism. Heavy metal removal is attributed to ion exchange and chemisorption within the zeolite pores, involving interactions with nitrogen lone pairs.

Synthesis and Structure Determination by 3D Electron Diffraction of the Extra‐large Pore Zeolite ITQ‐70

AbstractIn this study, we present the synthesis, characterization, and structural analysis of a novel zeolite, ITQ‐70, using 3D electron diffraction. This unique material was synthesized under alkaline conditions, employing tetrakis(diethylamino)phosphonium as an organic structure‐directing agent, leading to the formation of a pure silica zeolite. ITQ‐70 is distinguished by its extra‐large pore apertures, which extend along all three axes and intersect one to the other. A notable feature of this zeolite is the presence of structurally ordered defects in very high concentrations (38 % of the silicon atoms). As a result, ITQ‐70 exhibits the lowest framework density (10.0 T/1000 Å3) ever reported for any zeolite except RWY (7.6 T/1000 Å3), which contains sulfur instead of oxygen connecting T‐atoms.

In situ visualisation of zeolite anisotropic framework flexibility during catalysis

Zeolites exhibit framework flexibility driving their chemical and catalytic properties. Since the zeolitic pores are extremely small, a slight strain generated in the crystal induces compelling changes in shape, connectivity, accessibility, and the framework chemical properties. These modifications affected the adsorption and desorption of reactants/products and the diffusion within the channels during reaction. Using in situ 3D Bragg coherent X-ray diffraction imaging, we unveil the dynamics of the zeolite structure during catalysis, contraction and/or expansion of its framework also known as zeolite framework flexibility. We imaged three-dimensionally a single faujasite zeolite crystal during the ethanol dehydration reaction revealing anisotropic lattice dynamics simultaneously to guest molecules formation. Understanding zeolite flexibility could permit to tune zeolites properties towards potentially higher adsorption and selectivity.

Balancing the elementary steps via photo-assisted thermal catalysis for boosting propane dehydrogenation

Balancing kinetics behavior is a significant priority in chemical reactions especially involving two or more elementary steps. Propane dehydrogenation (PDH), usually involves a slower 2nd C-H activation step at a low temperature, resulting in heat waste for overcoming a higher energy barrier of the 2nd dehydrogenation. Herein, we develop one Photo-assisted Thermal PDH process (PTPDH) based on PtZn clusters encapsulated in porous MFI zeolite, which effectively balances the kinetic elementary steps via exciting the ground state electrons of the active sites to the positively charged -C3H7 fragments, achieving a 23.4 % growth ratio (from 39.6 to 51.3·10−8 mol·g−1·s−1) with the assistance of ∼5 suns light intensity at 400 °C. The comparison between the temperature-dependent and light intensity-dependent kinetic parameters confirmed that the non-thermal effect instead of the photo-to-thermal effect dominates the PTPDH process. Furthermore, the Lewis acidity-activity correlation experiments, in-situ radiation mass spectrometry and the H2 co-feeds experiment indicate that the hot electrons instead of the holes play a more significant role in propylene production. Last, the in-situ Drifts-MS technique and DFT calculations demonstrate light radiation conduce to the electron transition from metal to the unpopulated electronic states of -C3H7 fragments, while not conducing to the adsorbed C3H8 molecule, thus selectively promoting the 2nd dehydrogenation process and achieving a balanced chemical kinetic condition. Our findings demonstrate that Photo-assisted Thermal PDH is a promising method for balancing the 1st and 2nd dehydrogenation processes.

Use of Modified Silica as Selective Adsorbent on Exhaust and Dissolved Gases

Emissions are substances that enter the air, whether or not they have the potential as pollutants. Emission gases can have adverse effects on the health of living beings, especially humans, and can contribute to an increase in the Earth's temperature. Therefore, separation efforts are needed to minimize the negative impacts caused by them. Adsorption method was categorized as absorption, cryogenic distillation, and membrane. Although there were shortcomings in adsorbing emission gases through the method, it remained a promising approach. Adsorption was recognized for its economic viability, technological effectiveness, thermally stability, corrosion resistance, high load capacity, and tunable surface properties. However, adsorption materials were categorized as porous carbon, zeolites, metal-organic frameworks (MOFs), porous polymers, and porous silica. A significant limitation of the method was its susceptibility to decreased capacity in the presence of water vapor. The analysis results showed that porous silica became a superior adsorption material due to its high porosity, which facilitated rapid gas diffusion. To enhance selectivity and adjust pore size, material modifications, particularly silica, became necessary. This showed that surface modification for silicasupported the improvements in selectivity and pore size.

Cultivation of Microalgae Mixed Culture from Mahoni Small Lake UI Campus Depok using Zeolite Substrate with Varying Pb Concentration

Research on the cultivation of mixed cultures of Situ (small lake) Mahoni UI Campus Depok has been done. This research was a preliminary study to measure and compare the growth of Situ Mahoni mixed cultures microalgae grown in Bold's Basal Medium (BBM) with addition of zeolite and without addition of zeolite, and varying concentrations of heavy metal Pb. The concentrations of heavy metal Pb used were 0 ppm, 20 ppm, 40 ppm, 60 ppm, 80 ppm, and 100 ppm for two treatments. The results of this research were that the growth of mixed cultures with the addition of zeolite had the highest abundance of 8.800 cells/mL on day 5 (T5) at a Pb concentration of 40 ppm. Meanwhile, the growth of mixed culture without the addition of zeolite had the highest abundance of 21.700 cells/mL on day 10 (T10) at a Pb concentration of 60 ppm. The growth of microalgae mixed cultures in the medium without addition of zeolite was higher than using zeolite. The activation of zeolite pores causes the microalgae growth is relatively lower. This work aimed to study the growth of a mixed cultures microalgae in varying concentrations of Pb with and without the addition of zeolite

Investigation of hydrolysis of sugarcane bagasse into glucose over solid acid HSO3-ZSM-5 zeolite for fermentation to bioethanol

ABSTRACT In the pursuit of sustainable energy sources, biomass has emerged as a promising alternative to fossil fuels due to its renewability and carbon neutrality. This current work presents the application of solid acid zeolite catalyst for biomass hydrolysis into reducing sugar for fermentation. Sulfonated ZSM-5 zeolite was prepared by grafting sulfonic acid group on the surface and/or into the pores of porous ZSM-5 zeolite and characterized by several analyses. The as-synthesized HSO3-ZSM-5 zeolite was then investigated as a solid acid catalyst for the hydrolysis of alkaline pretreated sugarcane bagasse (SB). Containing sulfonic acid groups – a very strong acid – on the surface, HSO3-ZSM-5 zeolite presented high catalytic activity and high efficiency in the hydrolysis of SB biomass. When the hydrolysis was carried out under optimal conditions, approximately 106.8 g/L of reducing sugar including of glucose, xylose, arabinose, and cellobiose was recovered. 86.65% fermentable sugars could be achieved after catalytic hydrolysis, and 48.7% of SB in total was converted to reducing sugar and others. Moreover, this solid acid catalyst can be reused impressively several times with no significant loss in catalytic activity. The sugar hydrolyzate could be used for fermentative production of bio-ethanol. Results indicated the possibility of using solid acid zeolite in the hydrolysis of lignocellulose to generate sugars that can be further applied in biofuel or chemical manufacturing.

A hierarchical porous Fe3O4-COOH@H-ZIF-67 composite as magnetic solid-phase extraction adsorbent for benzimidazole pesticides

A hierarchical porous structural magnetic zeolite imidazolate framework-67 composite (Fe3O4-COOH@H-ZIF-67) was prepared through directly mixing the H-ZIF-67 and glutaric anhydride functionalized Fe3O4 nanospheres, of which the H-ZIF-67 was synthesized through a double template pore size regulation method. The successful preparation of Fe3O4-COOH@H-ZIF-67 composite was confirmed based on the material characterization using different techniques. The prepared composite was applied in the efficient removal of four benzimidazole pesticides (BZDs) in water using magnetic solid-phase extraction (MSPE) process. The results of static and dynamic adsorption experiments indicate that the adsorption of BZDs on Fe3O4-COOH@H-ZIF-67 follow pseudo-second-order kinetics, the Langmuir model fitted well with the adsorption data (R2 are all higher than 0.9969), and the maximum adsorption capacity for BZDs are 7.44–31.11 mg/g. Meanwhile, the adsorption mechanism study indicate that both hydrogen bonding and coordination play important roles during the adsorption process of BZDs. Finally, the developed MSPE method was combined with HPLC analysis and applied in the removal of BZDs from simulated pesticides wastewater. The removal rate was 82.76–96.18 %, and the treated samples met the requirements of the maximum residue limits of CBZ in the national standard GB 21523–2008. In addition, the adsorbent can be used at least three times and the extraction efficiency changed within 3 % after being stored in dry atmosphere at room temperature for 90 days. The results of this work manifested that Fe3O4-COOH@H-ZIF-67 composite can be used for removal and analysis of BZDs in complex samples.

Fabrication of yeast engineered porous 13X adsorbent layers for CO2 capture

This study investigates a novel environmentally friendly coating technique using yeast fermentation to obtain super porous Zeolite 13X adsorbent layers through freeze-drying technique for CO2 capture applications. Several mass ratios of sugar to yeast were used to control the porosity and pore sizes in the adsorbent layer. A unique peeling process was integrated to obtain foamy, hollow structures to have deeper layer accessibility of adsorbent for adsorption applications. These coated adsorbent layers were experimentally characterized as a function of the mass ratio of sugar to yeast and adsorbent solid fraction. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FT-IR) are used to analyze the coated layers. The void fraction for coated samples is found to vary between 0.48 and 0.56, making the samples applicable for adsorption applications. Adsorption performance experiments are performed to test the coated samples' performance compared to 13X powder. Due to their simplistic fabrication, cost-effectiveness, rapid pore formation, and high adsorption capacity, these porous 13X layers hold potential for large-scale fabrication and CO2 capture applications.

Non-linear kinetic model of coke deactivation in methanol-to-gasoline conversion: Effects of nano and micro ZSM-5 crystals

Methanol-to-gasoline conversion over ZSM-5 catalysts, a non-petroleum carbon fuel process, is significantly impacted by coke deposition, which deactivates the catalyst by blocking zeolite pores during the reaction and diffusion process. This study investigated the differences in coke species development and deactivation using a non-linear kinetic model, comparing microcrystalline ZSM-5 with longer pore lengths to nanocrystalline ZSM-5 with shorter pores, both tested at 350°C. Catalyst and coke were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed oxidation (TPO), thermogravimetric analysis (TGA), and an elemental analyzer. Micro ZSM-5 initially achieved 99 % conversion but rapidly dropped to 61 % due to coke buildup, while nano ZSM-5 maintained over 98 % conversion for 24 hours before declining, highlighting the superior catalytic durability of shorter pores. Micro ZSM-5 showed faster coking, accumulating 7.19 % coke with higher temperature-resistant graphitic coke, whereas nano ZSM-5 exhibited a lower coke buildup of 4.56 %, forming primarily amorphous coke. A two-step non-linear kinetic model for soft and hard coke oxidation was applied, with the second-order model providing the highest correlation coefficient. The activation energy for coke decomposition was influenced by pore length, revealing distinct kinetic behaviors for hydrogen-deficient graphitic coke and amorphous coke. This study underscores the importance of zeolite pore structure on coke formation, deposition patterns, and catalytic durability, offering deeper insights into the methanol-to-gasoline conversion process.

Advanced Synthesis of Hierarchically Porous Zeolite Catalysts Utilizing Biomass Templates for the Catalytic Pyrolysis of Stearic Acid into Short-Chain Olefins.

In this study, hierarchically porous ZSM-5 catalysts were fabricated by one-pot assembling ZSM-5 particles onto diverse biomass templates (e.g., rice husk, tea seed husk, tung shell, and coconut shell), wherein the biomass template was transformed into bio-SiO2 or biochar depending on the calcination conditions. The biotemplated ZSM-5 variants, including ZSM-5(RH), ZSM-5(TSH), ZSM-5(TS), and ZSM-5(CS), exhibited significantly improved deoxygenation performance, achieving ∼100.0% deoxygenation efficiency as compared to the untemplated ZSM-5 catalyst (85.3%). Among them, the ZSM-5(TSH) catalyst exhibited the best performance, accompanied by 100% conversion, 99.6% deoxygenation rate, and 82.3% olefin selectivity. Interestingly, the product distribution over biotemplated ZSM-5 was dominant C4=-C8= (selectivity of ∼100% in total olefins), while long-chain olefins (C9=-C17=) was the major product (selectivity of 57.3%) over the untemplated ZSM-5. Moreover, molecular dynamics (MD) simulations revealed that biotemplated ZSM-5 exhibited superior diffusion coefficients of stearic acid (reaction substrate) and anthracene (coke precursor) compared to the untemplated ZSM-5, indicating higher self-diffusion rates and consequently superior activity and stability in the catalytic pyrolysis reactions. Furthermore, in situ DRIFTS results showed stearic acid over ZSM-5(TSH) primarily was converted to the C17H36 intermediate mainly via the decarboxylation route, followed by dehydrogenation pyrolysis and C-C breaking reactions into C4=-C8= products. Overall, this work developed an effective strategy for manufacturing hierarchically porous zeolite catalysts using biomass-derived bio-SiO2 or biochar as the platform.

Unraveling Molecular Diffusion Behaviors on the Acidic Sites of H‐ZSM‐5 Zeolite Using Time‐Resolved In Situ FT‐IR Technique

AbstractZeolites, renowned for their abundant crystalline structures and moderate acidities, have garnered significant attention in industrial chemical processes. Among them, the diffusion behaviors of various hydrocarbons within zeolite play a pivotal role due to their profound impact on product selectivity and separation efficiency. While acid sites are essential in determining the catalytic performance of zeolites, their effect on intra‐crystalline diffusivities has often been neglected in catalyst design. Herein, we employ a homemade time‐resolved in situ Fourier Transform Infrared (TR in situ FT‐IR) spectroscopy to investigate the intricate interplay between Brønsted acid sites and various probe molecules. Our study reveals that an augmentation in the density of Brønsted acid sites within H‐ZSM‐5 zeolites remarkably enhances the diffusivity of 1‐butene, in stark contrast to the behavior observed for iso‐butane. This contrasting effect in diffusivity is attributed to the distinct nature of interactions between alkenes and alkanes with Brønsted acid sites. Specifically, the π‐H interactions between alkenes and acid sites act as a driving force, propelling the alkene molecules forward through the zeolite pores. These findings offer valuable insights into designing tailored zeolites with specific acid site properties, controlling the transport behaviors of various probe molecules, and promising new avenues for catalysis and separation.

Cu nanoparticles immobilized in mesopores generated in zeolite for high-performing CO2 hydrogenation to methanol

Copper nanoparticles (Cu NPs) are commonly used as catalyst active components in CO2 hydrogenation reactions. However, they often lose their catalytic activity due to sintering in most reaction environments. This study explores a solution for Cu-supported catalysts used for methanol production from CO2 hydrogenation by fixing Cu NPs in the mesopores generated in zeolite. Mesopores were generated in NaY zeolite by partially dealuminating its framework. High-resolution (scanning) transmission electron microscopy (HR(S)TEM) and CO adsorption measurements confirm that the synthesized mesoporous zeolite-supported Cu NPs are highly dispersed and fixed within the mesopores. In comparison with conventional microporous zeolite-supported Cu NPs (2 wt%), Cu NPs (2 wt%, average size of 2.2 nm) in mesoporous zeolite increased methanol production from ∼26 mmolgCu−1h−1 to approximately 56 mmolgCu−1h−1 at 250 °C. By further modifying the mesoporous zeolite with Zr (2 wt%), Cu NPs increased in size, and the methanol production rate increased approximately 2.2 folds to 125 mmolgCu−1h−1 under similar conditions due to zeolite electronic modification and the newly formed Zr-zeolite/Cu interface. However, the addition of Zr significantly increased the Cu NP size and moved part of them out of the mesopores, lowering their stability. In situ DRIFTS experiments reveal CO2 hydrogenation proceeds through the formate route via a direct formation of dominantly carbonate (*CO3), which hydrogenates to formate (*HCOO) and traces of methoxy (*H3CO), and subsequently methanol (CH3OH). This study reports the design of active and stable catalysts for CO2 hydrogenation to methanol by engineering Cu NPs in zeolite pores.

Stability and Dynamics of Zeolite-Confined Gold Nanoclusters.

Nanoengineered metal@zeolite materials have recently emerged as a promising class of catalysts for several industrially relevant reactions. These materials, which consist of small transition metal nanoclusters confined within three-dimensional zeolite pores, are interesting because they show higher stability and better sintering resistance under reaction conditions. While several such hybrid catalysts have been reported experimentally, key questions such as the impact of the zeolite frameworks on the properties of the metal clusters are not well understood. To address such knowledge gaps, in this study, we report a robust and transferable machine learning-based potential (MLP) that is capable of describing the structure, stability, and dynamics of zeolite-confined gold nanoclusters. Specifically, we show that the resulting MLP maintains ab initio accuracy across a range of temperatures (300-1000 K) and can be used to investigate time scales (>10 ns), length scales (ca. 10,000 atoms), and phenomena (e.g., ensemble-averaged stability and diffusivity) that are typically inaccessible using density functional theory (DFT). Taken together, this study represents an important step in enabling the rational theory-guided design of metal@zeolite catalysts.

Tailor-made the ultrathin nanosheet and acid site accessibility of mordenite zeolite for carbonylation of dimethyl ether

Precisely tailored nano-morphology and crystal growth endures mordenite (MOR) zeolites with reduced internal diffusion resistance, enabling greater accessibility of existing acid sites to further stimulate catalysis. Controllable synthesis nanosheet MOR zeolite thinner than 20 nm along at least one dimension is highly attractive but remains great challenge. Herein, c axis along the [001] direction shortened MOR nanosheets with a thickness of 10–20 nm was synthesized. As expected, the mass transfer performance over the nanosheet sample is significantly improved by 2.5 times compared with the conventional nano-morphology. Furthermore, more Brønsted acid sites (BAS) can be induced into 8-membered ring (8-MR) pores in the nanosheet MOR zeolite. The conversion of dimethyl ether (DME) to methyl acetate over the ultrathin MOR zeolite is increased from 17.4 % to 71.7 % compared to that of the conventional nanoparticle. The DME conversion was stable at 70.0 % after reaction 80 h, when the acid sites located in 12-membered ring pores was poisoned by the pyridine molecule. Unexpectedly, we discovered that the desorption behavior of pyridine is also influenced by the accessibility of acid site, not only by the amount of BAS in 8-MR. The unique nanosheet structure with short c axis reduces the spatial stability of pyridine adsorbed on BAS in the 8-MR side pocket and the BAS in the 8-MR side pocket can be recovered at lower temperatures. Herein, a new insight into of DME carbonylation catalyzed by ultrathin nanosheet of MOR zeolite is revealed.

Solidifying High-Concentration Electrolytes Using Faujasite as Nanosized Porous Zeolite Additive for Solid-Type Batteries

Solidifying High-Concentration Electrolytes Using Faujasite as Nanosized Porous Zeolite Additive for Solid-Type Batteries

Electrolytic manganese residue and red mud co-treatment: Synthesizing zeolite X and adsorbing leaching solution from electrolytic manganese residue

Electrolytic manganese residue (EMR) and red mud (RM) are solid wastes from electrolytic metallic manganese and alumina production. These wastes continue to accumulate, causing significant environmental damage and resource waste. To solve these problems, porous zeolite X (ERZ) was synthesized with EMR and RM as the main raw materials. ERZ was then employed to adsorb the leaching solution generated during EMR purification. Also, an investigation was carried out to ascertain the most favorable parameters for the synthesis of zeolite, and the resulting ERZ was characterized. The results indicated that the synthesized ERZ exhibits excellent crystallinity, high thermal stability, and a large specific surface area. Next, solid-state NMR (SSNMR), XRD, and Raman spectroscopy were used to characterize the ERZ synthesis process: the structural units of X zeolite are β cages and 4Rs. Additionally, the study examined the adsorption impact of ERZ on impurity ions in the leaching solution, revealing that the adsorption mechanism is chemisorption. Furthermore, the effective regeneration of ERZ demonstrated its significant practical utility. To summarize, this study presents a new feasible way for effectively utilizing EMR and BA.