Specific Pore Research Articles

Preparation of sludge-derived spinel ferrite nanoparticles for highly efficient adsorption of Pb(II) from water: Adsorption behaviour and mechanism interpretation via advanced statistical physics model

Because proper disposals of municipal sewage sludge and lead-containing wastewater are still open questions, the novel sludge-derived mesoporous nanospinel ferrite adsorbents were prepared from municipal sewage sludge (S-MZF) and its incineration ash (A-MZF) for Pb(II) removal from water. S-MZF and A-MZF had similar mesoporous structures with an average pore size at around 4.13–5.51 nm. A-MZF displayed a larger specific surface area (254 m2/g) and pore volume (0.3 m3/g) but inferior magnetic property, while S-MZF showed abundant surface functional groups and higher saturation magnetization (12.3 emu/g). The adsorption capacity of S-MZF and A-MZF for Pb(II) was close to each other at 50 °C, reaching 160 mg/g. Initial adsorption of A-MZF for Pb(II) was dominated by intraparticle diffusion, while the evident liquid film diffusion existed in that of S-MZF. Advanced statistical physics modeling found that multiple divalent lead ions were anchored simultaneously by each site of S-MZF mainly via multi-interactions where physical force and precipitation played a key role, while each site of A-MZF anchored only one Pb(II) ion by the physical interaction. As a result, the adsorption capacity of S-MZF mainly depended upon the number of Pb(II) ions adsorbed by each active site, while the available density of active sites on the surface of A-MZF primarily controlled its adsorption capacity for Pb(II).

Cu0·1In0·01/S-1 catalysts with high efficiency towards methanol steam reforming

Cu0·1/S-1, Cu0·1Zn0·01/S-1, Cu0.1Inx/S-1 (x = 0.01, 0.03, 0.05) and Cu0·1Ce0·01/S-1 were successfully prepared with S-1 as the carrier material and applied to methanol steam reforming (MSR) reaction. To further explore its chemical and physical properties, XRD, BET, SEM-EDS, ICP, FTIR, H2-TPR, NH3-TPD, CO2-TPD, and Raman were used to characterize the synthetic S-1 zeolite catalysts. The measured physicochemical properties revealed that utilizing S-1 zeolite as the carrier effectively altered the size of the metal particles, enhancing their dispersion and reduction characteristics. Compared with five different types of S-1 zeolite catalysts, the Cu0·1In0·01/S-1 catalyst has a large specific surface area and pore size. It exhibited superior active metal dispersion, with the lowest reduction temperature for the active metal CuO. The catalyst also showed a high Lewis acid content on its surface, forming the In-Lewis acid site. Consequently, the Cu0·1In0·01/S-1 catalyst exhibits exceptional performance in methanol steam reforming for hydrogen production reactions. It exhibited the best performance with a methanol conversion rate of 100%, H2 selectivity of 100% under the conditions of 1 MPa, 250 °C, the S/C molar ratio of 2.5, and the WHSV of 0.5 h−1, which outperforms most of the reported catalysts in methanol steam reforming.© 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Repurposing Cotton Gin Trash for Cellulose Nanofibril-Silver Hybrid and Ultralight Silver-Infused Aerogel.

Cellulose nanofibril-silver (CNF-Ag) hybrid and ultralight silver-infused aerogel were produced using cotton gin trash (CGT), an abundant agro-waste material. This repurposing of CGT was achieved by exploiting its potential for CNF extraction and the in situ synthesis of silver nanoparticles (Ag NPs). CNFs were extracted from CGT through a mechanical shearing process. These CNFs served as a multifunctional nanotemplate for the controlled reduction of Ag ions, efficient nucleation, and stabilization of NPs, resulting in the production of a high concentration of Ag NPs (ca. 19 wt %) within the CNFs. Transmission electron microscopy images of cross-sectioned CNFs confirmed the uniform dispersion of NPs (ca. 18 nm diameter) inside the CNFs. Rietveld refinement analysis of X-ray diffraction patterns revealed that CNFs produced smaller Ag crystallites compared to CGT microparticles. The CNF-Ag hybrid was then fabricated into an aerogel using freeze-drying, with its weight being light enough to rest on a cotton flower's stamen. The infusion of Ag NPs led to approximately 20% reductions in the specific surface area and pore volume of the aerogel.

Effect of ball milling activation on CO2 mineralization performance in fly ash and fire resistance capabilities of mineralized product

Coal-fired power generation has always been a major energy supply source globally. However, a large amount of CO2 is emitted with the combustion of coal resources, and fly ash, a by-product of coal combustion, is also accumulated in large quantities. The application of CO2 mineralization in fly ash can not only reduce CO2 emission but also effectively manage industrial waste, thereby promoting environmental sustainability. This paper used the mechanical ball milling method to activate fly ash and investigated the effects of ball milling time and speed on the CO2 sequestration in fly ash. At 30 min ball milling time and 400 r/min ball milling speed, the modified fly ash achieves a good CO2 sequestration capacity of 81.70 gCO2/kgFA. Compared with raw fly ash, the CO2 consumption of treated fly ash is higher at 75.41 mmol/mL. The specific surface area and pore volume of treated fly ash are larger at 1.57 m2/g and 4.33 cm3/kg respectively, which is beneficial for enhancing mass transfer capacity and the carbonation effect. As the ratio of mineralized product/coal increases from 0.5 to 4, the crossing-point temperature increases from 157.20 °C to 165.15 °C. Based on the experimental results, the paper discussed the mechanism of ball milling activation to enhance the carbonation effect of fly ash. This study provides theoretical references for the environmentally friendly utilization of fly ash.

Co-pyrolysis development of waste tire-sludge adsorbent by mixed of waste tires and oily sludge

To facilitate resource utilization of waste tires (WT) and oily sludge (OS), waste tire-sludge adsorbent (WTSA) was developed using co-pyrolysis technology, and its effectiveness in adsorbing crude oil was investigated. The study revealed that the optimal preparation conditions for WTSA included a 1.5:1 mass ratio of WT to OS, a co-pyrolysis temperature of 600 ℃, a co-pyrolysis holding time of 2 hours, and a co-pyrolysis heating rate of 15 ℃/min. The surface of WTSA exhibited numerous pores and cracks with varying shapes and sizes. The dominant pore structures were found to be mesopores and macropores. The carbon content of WTSA was measured to be 89.95%. Moreover, the BET specific surface area, pore volume, and average pore size were determined to be 686.81 m2/g, 0.74 cm3/g, and 5.91 nm, respectively. In the crude oil adsorption test, WTSA demonstrated a comparable adsorption capacity to activated carbon (AC), but with a more attractive initial adsorption rate. Furthermore, thermal regeneration treatment was found to significantly enhance the lipophilic properties of WTSA, leading to an increase in its initial adsorption rate. The adsorption capacity of regenerated WTSA was also found to be relatively stable, making it an ideal solution for emergency crude oil spill cleanups. Compared to AC, WTSA can be recycled and reused multiple times, making it a more sustainable and cost-effective option.

Reclaiming selenium from water using aluminum-modified biochar: Adsorption behaviors, mechanisms, and effects on growth of wheat seedlings

Although selenium is an essential nutrient, its contamination in water poses serious risks to human health and ecosystems. In this study, aluminum-modified bamboo biochar (Al-BC) was developed to reclaim Se(VI) from water. Compared to pristine biochar (BC), Al-BC had a larger specific surface area (176 m2/g) and pore volume (0.180 cm³/g). The modification, achieved by loading AlOOH and Al2O3 particles onto the surface, enabled Al-BC to achieve a maximum adsorption capacity of 37.6 mg/g for Se(VI) within 2 h and remove 99.6% of Se(VI) across a pH range of 3–10. The main adsorption mechanism of Se(VI) involved electrostatic attraction, forming outer-sphere complexes between Se(VI) and AlOOH sites on the biochar. The bioavailability of Se sorbed on the spent biochar (Al-BC-Se) was thus evaluated. It was discovered that Al-BC-Se successfully released Se(VI), which impacted the growth of wheat seedlings. The Se content reached 134 μg/g dry weight (DW) in wheat shoots and 638 μg/g DW in roots, significantly exceeding normal selenium content (<40 μg/g DW). By successfully applying the modified biochar to capture selenium from water through adsorption and then reusing it as an essential nutrient in soil, this study suggests the promising feasibility of the "removal-collection-reuse" approach for the circular economy of selenium in wastewater.

Realizing the Direct Synthesis of High Silica IWS Zeolite with Improved Hydrothermal Stability.

Direct synthesis of germanosilicate zeolites with low Ge content and improved hydrothermal stability is a great challenge. Herein, we successfully achieve the direct synthesis of IWS zeolite with a Si/Ge ratio higher than 4 for the first time. High silica IWS zeolites can be prepared in a wide range of Si/Ge ratios (4-16) by utilizing bulky 1,3-bis(1-adamantyl)-imidazolium (BAdaI+) as an efficient organic structure-directing agent from the concentrated synthesis gel under fluoride conditions. It is proven by a series of characterizations that Ge atoms preferentially occupy the double-four-ring (D4R) units. Theoretical calculations reveal the preferential interactions of guest organic structure-directing agents (OSDAs) and host IWS zeolites with different Si/Ge ratios. The introduction of more Ge atoms cannot improve the host-guest interaction when the BAdaI+ molecule is accommodated within the nanopores of IWS zeolite compared to other OSDAs. The obtained IWS zeolite shows an extremely high specific surface area (905 m2/g) and pore volume (1.31 cm3/g). Due to the low Ge content, IWS zeolite exhibits outstanding hydrothermal stability and experiences high temperature steam heating with no loss of crystallinity and only a slight loss of microporosity.

Efficient removal of organic pollutants on sponge-type inorganic adsorbent derived from spent cotton fiber/layered double hydroxides

For the whole life cycle of the textile industry, the disposal of printing and dyeing wastewater and the reuse of spent fibers were two of the main environmental problems. In this work, activated carbon fiber/layered double oxides (ACF/LDO) were prepared by the pyrolysis of spent cotton fiber/layered double hydroxides (LDH) composite. Compared to 2D structure LDH, 3D hierarchical ACF/LDO was formed by introducing activated carbon nanofibers as a skeleton. ACF/LDO had excellent adsorption properties for organic dye and the maximum adsorption capacity of acid red 27 (AR27) exceeded 800 mg/g. Due to the memory effect of LDH, the interconversion of ACF/LDO to ACF/LDH was observed during the adsorption and regeneration process. Meanwhile, the shrinkage and expansion of adsorbent occurred, which was similar to that of a sponge absorbing water. During the adsorption process, the average pore diameter of the adsorbent increased as ACF/LDO was converted to ACF/LDH, which increased the diffusion of organic dye inside the pores. On the contrary, the specific surface area and pore structure were restored during the regeneration process. Therefore, this composite displayed excellent adsorption capacity and repeatability, with no significant decrease was observed in adsorption capacity even after five consecutive cycles. The adsorption mechanism revealed that the removal of AR27 was dominated by electrostatic attraction and π-π interactions. The experiment provided a new strategy of treating wastewater with waste fiber.

β-Ketoenamine Porous Organic Polymers for High-Efficiency Carbon Dioxide Adsorption and Separation.

To mitigate the greenhouse effect, a number of porous organic polymers (POPs) has been developed for carbon capture. Considering the permanent quadrupole of symmetrical CO2 molecules, the integration of electron-rich groups into POPs is a feasible way to enhance the dipole-quadrupole interactions between host and guest. To comprehensively explore the effect of pore environment, including specific surface area, pore size, and number of heteroatoms, on carbon dioxide adsorption capacity, we synthesized a series of microporous POPs with different content of β-ketoenamine structures via Schiff-base condensation reactions. These materials exhibit high BET specific surface areas, high stability, and excellent CO2 adsorption capacity. It is worth mentioning that the CO2 adsorption capacity and CO2/N2 selectivity of TAPPy-TFP reaches 3.87 mmol g-1 and 27. This work demonstrates that the introduction of β-ketoenamine sites directly through condensation reaction is an effective strategy to improve the carbon dioxide adsorption performance of carbon dioxide.

Substrates with Tunable Hydrophobicity for Optimal Cell Adhesion.

Electrospinning is a technique used to create nano/micro-fibrous materials from various polymers for biomedical uses. Polymers like polycaprolactone (PCL) are commonly used, but their hydrophobic properties can limit their applications. To enhance hydrophilicity, nonionic surfactants such as sorbitane monooleate (Span80) and poloxamer (P188) can be added to the PCL electrospinning solution without altering its net charge density. These additions enable the successful production of PCL/P188 and PCL/Span80 fibrous substrates. In this study, P188 and Span80 are incorporated into the PCL solutions; they are successfully electrospun into PCL/P188 and PCL/Span80 substrates, respectively. PCL/P188 substrates show that until a specific P188 concentration, fiber and pore sizes are similar to PCL substrates. However, exceeding 0.30% P188 concentration enlarges fibers, impacting fiber uniformity at higher concentrations. Conversely, higher concentrations of Span80 result in thicker, less uniform fibers, indicating potential disruptions in the electrospinning process. Notably, both surfactants significantly improve substrate hydrophilicity, enhancing the adhesion and proliferation of fibroblasts, endothelial cells, and smooth muscle cells. P188, in particular, shows superior efficacy in promoting cell adhesion and growth at concentrations optimized for different cell types. Therefore, precise surfactant concentrations in the electrospinning solution can lead to the optimization of electrospun substrates for tissue engineering applications.

NiAl-LDHs-derived NiO/Al2O3 with high specific surface area for wide range hydrogen detection

The construction of heterojunctions is generally considered as one of the effective strategies to improve gas sensing performance. Herein, the NiO/Al2O3 (NAO) hybrid structure is constructed by calcining Ni–Al layered double hydroxides (NiAl-LDHs). The specific surface area and pore size of NAO are effectively regulated by changing the content of NaOH. The XPS and BET characterization results indicate that NAO-5 exhibits a high oxygen vacancy content, a large specific surface area (468.524 m2 g−1), and abundant pore size. The hydrogen (H2) sensitivity property of NAO was investigated, and NAO-5 exhibited outstanding gas sensing performance to 500 ppm H2 at 370 °C, including high response (10.524), fast response recovery speed (21 and 30 s), and wide detection range (0.1–5000 ppm). The improved gas property is mainly attributed to the increased oxygen vacancies and specific surface area. This study provides a feasible approach for NiAl-LDHs in H2 monitoring and early warning.

Photocatalytic removal of rhodamine B using a novel g–C3N4–organic solid waste biochar composite: Pathway, key factors, and mechanism

Over the past decades, water pollution caused by organic dyes has attracted extensive attention. The development of efficient, environmental friendly photocatalysts is a promising route for wastewater purification. Herein, a novel wild jujube shell derived biochar/g-C3N4 (BC/CN) composite has been prepared via a one-step calcination route. Although the specific surface area (9.37 m2/g) and pore size (14.57) of the BC/CN composite are smaller than those of g-C3N4, it exhibits enhanced photocatalytic activity. Especially, the 0.25-BC/CN composite (sour jujube shell powder/melamine ratio = 0.25) displays excellent photocatalytic activity, and can degrade ∼97.1 % of RhB under 40 min light irradiation, which is ∼46.51 times to that of pure g-C3N4. The actives species of h+, ·OH, ·O2− and 1O2 active species play the important roles in the photocatalytic system of the BC/CN composite. The results mechanistic study demonstrates that the enhanced photocatalytic activity of the BC/CN composite can be mainly attributed to the improved light absorption and charge separation efficiency of the catalyst. This work provides a simple method for preparing of novel highly efficient g–C3N4–based photocatalyts for wastewater purification, and provides a new idea for the recycling, and high-value utilization of the organic solid waste from traditional Chinese medicine.

Preparation of cellulose-based porous carbon fibers and their methylene chloride adsorption/desorption behaviors

Methylene chloride is a type of volatile organic compounds for which effective and economical treatment and recovery technologies need to be developed because it is impossible to reburn. In this study, a cellulose-based porous carbon fibers were prepared for the adsorption/desorption of methylene chloride. From the results, the specific surface area and total pore volume of cellulose-based porous carbon fibers were determined to be 1700–2220 m2/g and 0.69–1.03 cm3/g, respectively, and the micropore ratio was observed to be high. As the activation time increased, methylene chloride activity and methylene chloride retentivity increased from 51.75 % to 58.07 % and from 9.08 % to 14.92 %, respectively. Methylene chloride adsorption/desorption showed a high correlation with pore volume, Especially, methylene chloride retentivity had a linear relationship between the mesopore volume and mesopore ratio.

Research Progress on Saccharide Molecule Detection Based on Nanopores.

Saccharides, being one of the fundamental molecules of life, play essential roles in the physiological and pathological functions of cells. However, their intricate structures pose challenges for detection. Nanopore technology, with its high sensitivity and capability for single-molecule-level analysis, has revolutionized the identification and structural analysis of saccharide molecules. This review focuses on recent advancements in nanopore technology for carbohydrate detection, presenting an array of methods that leverage the molecular complexity of saccharides. Biological nanopore techniques utilize specific protein binding or pore modifications to trigger typical resistive pulses, enabling the high-sensitivity detection of monosaccharides and oligosaccharides. In solid-state nanopore sensing, boronic acid modification and pH gating mechanisms are employed for the specific recognition and quantitative analysis of polysaccharides. The integration of artificial intelligence algorithms can further enhance the accuracy and reliability of analyses. Serving as a crucial tool in carbohydrate detection, we foresee significant potential in the application of nanopore technology for the detection of carbohydrate molecules in disease diagnosis, drug screening, and biosensing, fostering innovative progress in related research domains.

Effect of Microwave Irradiation on Lead Adsorption Properties of Vermiculite with Different Particle Sizes.

The expansion of vermiculite using microwave irradiation is an environmentally friendly and efficient method that can enhance the material's adsorption performance. This study investigated the microwave irradiation of vermiculite with five different particle sizes (4/2/1/0.5/0.2 mm) and found that the adsorption capacity for Pb2+ increased with larger particle sizes. The equilibrium adsorption capacity reached 15.98 mg/g at 4 mm, representing a 45.01% improvement compared to 0.2 mm. The pseudo-second-order kinetic model effectively described the adsorption kinetics. No significant differences were observed in the specific surface area and pore size distribution of all samples. Thermogravimetric quantitative analysis revealed that larger particle sizes retained interlayer water more effectively. As the particle size decreased, the interlayer water content generally showed a decreasing trend. Fourier-transform infrared spectroscopy analysis also indicated that the -OH groups in larger particle sizes exhibited higher stability. The results suggest that the high content and stability of -OH groups may be key factors in the enhanced adsorption performance for Pb2+. This provides new insights for the preparation of environmentally friendly adsorbent materials rich in hydroxyl groups.

Exploration of the adsorption and desorption performance of volatile organic compounds by activated carbon with different shapes based on fixed-bed experiments

Activated carbon (AC) has been widely used in volatile organic compounds (VOCs) treatment of industrial exhaust gases. Rather than modifying specific pore size distributions and surface properties, altering the shape of AC offers a more feasible approach to enhance its adsorption performance. This study investigates the adsorption-desorption performance of two different shaped ACs with highly similar properties for the removal of VOCs. The clover-shaped AC (CSAC) has a 27.46% lower internal void fraction and a 39.10% higher external void fraction compared to cylindrical AC (CAC), resulting in denser packing and longer contact time with VOCs. Adsorption experiments showed the CSAC has 40% longer adsorption breakthrough (BT) times for ethanol, ethyl acetate, and n-hexane on average, and 20% higher saturation adsorption capacity per unit volume. CSAC also has higher partition coefficients, with the highest values for ethanol, ethyl acetate, and n-hexane being 0.0187, 0.0382, and 0.0527 mol kg−1·Pa−1, respectively. The desorption process for selected VOCs is non-spontaneous and endothermic. Optimal desorption conditions were identified as an inlet space velocity of 3535 h−1, a desorption temperature of 150 °C, and a pulsed inlet method. To investigate the possibility of the application of CSAC in real-world scenarios, xylene was chosen as a representative industrial VOC. Results showed CSAC has 20% higher BT time and saturation adsorption capacity for xylene compared to CAC under different bed heights. The desorption efficiency for xylene on both ACs is below 40%. With increasing xylene inlet concentration, the mass transfer zone (MTZ) height initially increases but stabilizes beyond 1704 mg m−3. At identical bed heights, the MTZ height of CSAC is 29% shorter than CAC, indicating a higher bed utilization efficiency.

Fe2O3/γ-Al2O3 and NiO/γ-Al2O3 catalysts for the selective catalytic oxidation of ammonia

Ammonia, a significant atmospheric pollutant, requires effective emission control due to its inherent toxicity and the generation of secondary pollutants like particulate matter. This control can be achieved through various methods, including catalytic processes. Therefore, our study focuses on evaluating the potential of catalysts based on iron oxide and nickel oxide supported on γ–Al2O3 for the selective catalytic oxidation of NH3 to N2 (NH3-SCO). The γ–Al2O3 was obtained by thermal decomposition of aluminum hydroxide, and 5 or 10 wt% of Fe or Ni was added through wetness incipient impregnation. XRD diffractograms confirmed the formation of the γ–Al2O3 phase. XRD, H2-TPR, and UV–vis DRS data showed the presence of Fe2O3, NiO, and NiAl2O4 in the catalysts. Introducing metal oxides onto the support led to a drop in the specific area, pore size, pore volume, and NH3 desorption, which was higher for the catalysts containing Fe. The catalysts were active in NH3-SCO, and the insertion of Fe or Ni was essential because it promoted a significant increase in the NH3 conversion (∼75 % Fe and ∼55 % Ni), compared to pure support (∼8 %), mainly from 400 °C. However, doubling the metal content has not resulted in a considerable increase in NH3 conversion. The N2 selectivity was higher for the catalysts containing Ni (∼85 %) from 400 °C compared to catalysts containing Fe (∼76 %). Such behavior was due to the larger surface area of the Ni-containing catalysts. Despite that, the 5Fe/γ–Al2O3 catalyst emerged as the most effective option for NH3-SCO applications, combining higher NH3 conversion and good N2 selectivity.

A novel 3D hierarchical NiFe-LDH/graphitic porous carbon composite as multifunctional adsorbent for efficient removal of cationic/anionic dyes and heavy metal ions

Developing effective adsorbents for wastewater purification is crucial, as excessive emissions of toxic dyes and heavy metal ions have been proven harmful to ecosystems and human health. A NiFe-layered double hydroxide/graphitic porous carbon (NiFe-LDH/GPC) composite was fabricated by introducing NiFe-LDH nanosheets into GPC via a simple hydrothermal method to utilize the advantages of both materials fully, and thus ultimately obtain a composite adsorbent with improved adsorption properties. The samples obtained were comprehensively characterized by various characterization means, and the effects of several critical influential factors on the pollutant uptake capability of the NiFe-LDH/GPC were also studied through batch experiments. The results show that the as-synthesized NiFe-LDH/GPC exhibits a three-dimensional (3D) fluffy ultrathin-wall hierarchical porous structure, which possesses a high specific surface area and pore volume separately up to 506.74 m2/g and 0.22 cm3 g−1 as well as a relatively narrow pore size distribution. These characteristics bring advantages to enhance the adsorption ability of the NiFe-LDH/GPC for cationic/anionic dyes and heavy metal ions such as congo red (CR), malachite green (MG) and hexavalent chrome (Cr(VI), which reached the maximum adsorption capacity of 1726.51 mg/g, 1157.11 mg/g and 155.72 mg/g under the optimum conditions, respectively. Meanwhile, the adsorption behavior can be well described by the pseudo-second-order kinetic model and Langmuir isotherm model, reflecting that the sorption process mainly occurred chemically in the adsorbent monolayer. Furthermore, the NiFe-LDH/GPC maintained relatively high adsorption performance after multicycle testing, manifesting its good recyclability and stability.

Preparation of porous imidazole-based poly(ionic liquid) adsorbents and their toluene adsorption performance.

Efficient, economical, and durable adsorbents are required to remove volatile organic compounds (VOCs) from air. Cross-linked polyvinylic ionic liquids (PVIC) with porous structures were synthesized by quaternizing 1-vinylimidazole (1VI) with 1-bromobutane to obtain 3-butyl-1-vinylimidazolium bromide (VIC), which was then co-polymerized with divinylbenzene (DVB) radicals. 1H NMR, 13C NMR, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and N2 adsorption-desorption isotherms were applied in characterizing the composites. Through modification of the polymer structure by adjustment of DVB concentration（the ratio of DVB concentration to VIC concentration was x: 1 (x=0.4, 0.6, 0.8, 1.0) and the product was named PVIC-s (s=2, 3, 4, 5)）, the optimal PVIC-4 pore structure was obtained, with a specific surface area and total pore volume of 192.5 m2 g-1 and 0.192 cm3 g-1, respectively. A toluene adsorption test verified the adsorption capacity. The adsorption behavior for VOCs, based on toluene, was investigated using adsorption breakthrough curves, adsorption kinetics, and isotherms. The adsorption process is well describing by the Bangham kinetic and Langmuir isotherm models. The dynamic adsorption of toluene followed the order PVIC-4 > PVIC-5 > PVIC-3 > PVIC-2. The optimum toluene adsorption by PVIC-4 was 264.4 mg g-1 as a result of its excellent pore structure. PVIC-4 also performed well in terms of recovery and has potential for the removal of VOCs from air.

Properties of Biochar Prepared by Solar Pyrolysis and Its Adsorption of Cu&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt; in Water

This study investigates the potential of biochar produced via a solar pyrolysis system and its effectiveness in removing copper (Cu&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt;) ions from water, presenting a sustainable and energy-efficient method for biochar production and biomass recycling. Two common agricultural and livestock wastes, corn straw and cow dung, were used as raw materials to produce biochar. These materials underwent solar pyrolysis under limited oxygen conditions to produce biochar, which was then compared to biochar produced via traditional pyrolysis. The comparison involved elemental analyses, infrared spectroscopy, scanning electron microscopy, and specific surface area and pore size analysis to highlight differences in their physical and chemical properties. Adsorption experiments were conducted to evaluate the adsorptive capacity of biochar for copper ions (Cu&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt;) from water, determining the optimal pH conditions and underlying adsorption mechanisms. The findings reveal that biochar produced through solar pyrolysis exhibits similar properties and Cu&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt; adsorption capacities to those prepared by traditional methods. Specifically, cow dung biochar demonstrated a higher adsorption capacity for Cu&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt; compared to corn straw biochar. The Cu&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt; adsorption by corn straw biochar followed the Langmuir isothermal adsorption model and pseudo-second-order kinetic equation, whereas cow dung biochar conformed to the Freundlich isothermal adsorption model and pseudo-second-order kinetic equation. By demonstrating the comparable efficacy of solar pyrolysis biochar in heavy metal adsorption, this study highlights its potential for sustainable environmental remediation and biomass utilization.