Microbial Targeted Degradation Pretreatment: A Novel Approach to Preparation of Activated Carbon with Specific Hierarchical Porous Structures, High Surface Areas, and Satisfactory Toluene Adsorption Performance

Zr-based multivariate metal-organic framework for rapid extraction of sulfonamide antibiotics from water and food samples

Based on multiple ligands strategy, a series of multivariate metal organic frameworks (MTV-MOFs) named as PCN-224-DCDPSx were prepared using one-pot solvothermal method to extract and remove sulfonamide antibiotics (SAs). The pore structure and adsorption performance can be further regulated by modulating the doping ratios of medium-tetra(4-carboxylphenyl) porphyrin and 4,4'-dicarboxydiphenyl sulfones. The MTV-MOFs of PCN-224-DCDPS1.0 possesses very large specific surface area (1625 m2/g). Using PCN-224-DCDPS1.0 as sorbent, a dispersive solid-phase extraction method was developed to extract and preconcentrate SAs from water, eggs, and milk prior to high performance liquid chromatography analysis. The limits of detection of method were determined between 0.17 and 0.27 ng/mL with enrichment factors ranging 214-327. The adsorption can be finished within 30 s, and the recovery rate remains above 80 % after 10 repeated uses. The adsorption capacities of sorbent were determined from 300 to 621 mg/g for sulfadiazine, sulphapyridine, sulfamethoxydiazine, sulfachlorpyridazine, sulfabenzamide, and sulfadimethoxine. The adsorption mechanisms were investigated and can be attributed to π-π interactions, hydrogen bonds, and electrostatic interactions. This work represents a method for preparation of MTV-MOFs and uses as sorbent for extraction and enrichment of trace pollutants from complex samples.

Carbon based nanocomposites, surface functionalization as a promising material for VOCs (volatile organic compounds) treatment

Urban residential and industrial growth development affects sustainable and healthful indoor environments. Environmental issues are a global problem. The deterioration of indoor air quality has prompted the creation of several air cleansing techniques. This review explains how carbon-based materials have influenced the development of air purification systems using photocatalysis. These carbon-based materials offer unique properties and advantages in VOC removal processes. Biochar, produced from biomass pyrolysis, provides an environmentally sustainable solution with its porous structure and carbon-rich composition. Carbon quantum dots, with their quantum confinement effects and tunable surface properties, show promise in VOC sensing and removal applications. Polymers incorporating reduced graphene oxide demonstrate enhanced adsorption capabilities owing to the synergistic effects of graphene and polymer matrices. Activated carbon fibers, characterized by their high aspect ratio and interconnected porosity, provide efficient VOC removal with rapid kinetics. With their unique electronic and structural properties, graphitic carbon nitrides offer opportunities for photocatalytic degradation of VOCs under visible light. Catalysts integrated with MXene, a two-dimensional nanomaterial, exhibit enhanced catalytic activity for VOC oxidation reactions. Using various carbon-based materials in VOC removal showcases the versatility and effectiveness of carbon-based approaches in addressing environmental challenges associated with indoor air pollution. Metal-organic-framework materials are carbon-based compounds. It examines the correlation between VOC mineralization and specific characteristics of carbon materials, including surface area, adsorption capability, surface functional groups, and optoelectronic properties. Discussions include the basics of PCO, variables influencing how well catalysts degrade, and degradation mechanisms. It explores how technology will improve in the future to advance studies on healthy and sustainable indoor air quality.

Microbial etch: A novel construction method of functionalized biochar for enhanced uranium extraction in radioactive wastewater

Nuclear energy is playing an increasingly important role on the earth, but the nuclear plants leaves a legacy of radioactive waste pollution, especially uranium-containing pollution. Straw biochar with wide sources, large output, low cost, and easy availability, has emerged as a promising material for uranium extraction from radioactive wastewater, but the natural biomass with suboptimal structure and low content of functional groups limits the efficiency. In this work, microbial etch was first came up to regulate the biochar's structure and function. The surface of the biochar becomes rougher and more microporous, and the mineral contents (Ca, P) indirectly increased by microbial etch. The biochar was modified by calcium phosphate and exhibited a remarkable uranium extraction capacity of 590.8 mg g-1 (fitted value). This work provides a cost-effective and sustainable method for preparing functionalized biochar via microbial etch, which has potential for application to uranium extraction from radioactive wastewater.

Degradation of thiocyanate by Fe/Cu/C microelectrolysis: Role of pre-magnetization and enhancement mechanism

Thiocyanate (SCN-), a non-volatile inorganic pollutant, is commonly found in various types of industrial wastewater, which is resistant to hydrolysis and has the potential to be toxic to organisms. Premagnetized iron-copper-carbon ternary micro-electrolytic filler (pre-Fe/Cu/C) was prepared to degrade SCN-. Pre-Fe/Cu/C exhibited the most significant enhancement effect on SCN- removal when magnetized for 5 min with an intensity of 100 mT, and the SCN- removal rate was the highest at an initial pH of 3.0 and an aeration rate of 1.6 L/min. The electrochemical corrosion and electron transfer in the pre-Fe/Cu/C system were confirmed through SEM, XPS, FTIR, XRD, and electrochemical tests. This resulted in the formation of more corrosion products and multiple cycles of Fe2+/Fe3+ and Cu0/Cu+/Cu2+. Additionally, density functional theory (DFT) calculations and electron paramagnetic resonance (EPR) were utilized to illustrate the oxygen adsorption properties of the materials and the participation of reactive oxygen species (1O2, ·O2-, and ·OH) in SCN- removal. The degradation products of SCN- were identified as SO42-, HCO3-, NH4+, and N2. This study introduced the use of permanent magnets for the first time to enhance Fe/Cu/C ternary micro-electrolytic fillers, offering a cost-effective, versatile, and stable approach that effectively effectively enhanced the degradation of SCN-.

Biological pretreatment with white rot fungi for preparing hierarchical porous carbon from Banlangen residues with high performance for supercapacitors and dye adsorption

White rot fungi possess superior infiltrability and biodegradability on lignocellulosic substrates, allowing them to form tailored microstructures which are conducive to efficient carbonization and chemical activation. The present research employed white rot fungus pretreatment as a viable approach for preparing porous carbon from Banlangen residues. The resultant F-A-BLGR-PC prepared by pretreating Banlangen residues with white rot fungi followed by carbonization and activation has a hierarchical porous structure with a high specific surface area of 898 m2 g-1, which is 43.4% greater than that of the unprocessed sample (R-BLGR-PC). When used as an electrode for supercapacitors, the F-A-BLGR-PC demonstrated a high specific capacitance of 308 F g-1 at 0.5 A g-1 in 6 M KOH electrolyte in three-electrode configuration. Moreover, the F-A-BLGR-PC based symmetric supercapacitor device achieved a superb cyclic stability with no obvious capacitance decay after 20,000 cycles at 5 A g-1 in 1 M Na2SO4 electrolyte. Additionally, the F-A-BLGR-PC sample was found to be an ideal adsorbent for removing methyl orange (MO) from water, exhibiting an adsorption ability of 173.4 mg g-1 and a maximum removal rate of 86.6%. This study offers a promising method for the preparation of a porous carbon with a high specific surface area in a biological way using white rot fungi pretreatment, and the derived carbon can not only be applied in energy storage but also in environmental remediation, catalysis, and so on.

Efficient Catalytic Elimination of Toxic Volatile Organic Compounds via Advanced Oxidation Process Wet Scrubbing with Bifunctional Cobalt Sulfide/Activated Carbon Catalysts

Advanced oxidation process (AOP) wet scrubber is a powerful and clean technology for organic pollutant treatment but still presents great challenges in removing the highly toxic and hydrophobic volatile organic compounds (VOCs). Herein, we elaborately designed a bifunctional cobalt sulfide (CoS2)/activated carbon (AC) catalyst to activate peroxymonosulfate (PMS) for efficient toxic VOC removal in an AOP wet scrubber. By combining the excellent VOC adsorption capacity of AC with the highly efficient PMS activation activity of CoS2, CoS2/AC can rapidly capture VOCs from the gas phase to proceed with the SO4•- and HO• radical-induced oxidation reaction. More than 90% of aromatic VOCs were removed over a wide pH range (3-11) with low Co ion leaching (0.19 mg/L). The electron-rich sulfur vacancies and low-valence Co species were the main active sites for PMS activation. SO4•- was mainly responsible for the initial oxidation of VOCs, while HO• and O2 acted in the subsequent ring-opening and mineralization processes of intermediates. No gaseous intermediates from VOC oxidation were detected, and the highly toxic liquid intermediates like benzene were also greatly decreased, thus effectively reducing the health toxicity associated with byproduct emissions. This work provided a comprehensive understanding of the deep oxidation of VOCs via AOP wet scrubber, significantly accelerating its application in environmental remediation.

Insights into the role of VOCs properties on thermal desorption behaviors of two porous polymeric resins

Desorption is a critical process in the recovery or post-treatment of adsorbents saturated with volatile organic compounds (VOCs). In this study, the thermal desorption behaviors for eight VOCs on hypercrosslinked polymeric resin (HPR) and macroporous polymeric resin (MPR) were investigated through isothermal desorption and temperature programmed desorption (TPD). Compared with MPR, HPR with more micropores exhibited a lower desorption rate constant, lower desorption efficiency and higher desorption activation energy due to the strong binding energy generated between VOCs molecules and narrow micropores. As the polarizability of VOCs increased, the desorption rate constants on two porous polymeric resins decreased, while the desorption activation energy showed an incremental trend. Excellent linear correlations were observed between VOC polarizability and desorption rate constants (R2 = 0.957 for HPR and R2 = 0.940 for MPR) as well as between VOC polarizability and desorption activation energy (R2 = 0.981 for HPR and R2 = 0.969 for MPR). Furthermore, a polyparameter linear free energy relationship (PP-LFER) was developed to explore the influences of intermolecular interactions on desorption behaviors of VOCs on porous polymeric resins. The results indicated that the dispersive interaction, which is directly related to polarizability of VOCs, was the primary factor influencing the desorption activation energy of VOCs on porous polymeric resins. The find from this study helps evaluate fleetly and availably the desorption properties of VOCs based on their polarizability.

Interfacial nanoarchitectonics of nickel phosphide supported on activated carbon for transfer hydrogenation of nitroarenes under mild conditions

Metal phosphides are promising catalysts for hydrogenation reactions due to their unique ability to generate active hydrogen species which are essential for desired reactions. In this work, the hydrogenation potential of nickel phosphide (Ni2P) is explored for the transfer hydrogenation of aromatic nitro compounds using hydrazine hydrate as hydrogen source. The Ni2P was supported on activated carbon (AC) to facilitate highly exposed active reaction sites. The as-synthesized Ni2P-AC catalyst showed excellent catalytic potential for the hydrogenation of nitro compounds to corresponding amines with 100% conversion efficiency and resulted in excellent yields. The reaction conditions were optimized by varying different reaction parameters, such as time, temperature, solvents, catalyst amount and hydrogen sources. The developed reaction protocol is highly selective for nitro compounds having reduction susceptible functional groups like -Cl, -Br, -CHO, etc. The structure-activity relationship of the Ni2P-AC was also examined which suggested that both acidic and basic sites present in Ni2P-AC catalyst plays crucial role in hydrogenation reaction. Besides, an in-depth insight into the reaction mechanism illustrates that the reaction proceeds via N-phenyl hydroxylamine as the reaction intermediate. In addition, decent recyclability and stability of Ni2P-AC catalyst demonstrates its highly versatile nature for potential large-scale applications. The use of highly efficient Ni2P-AC catalyst for hydrogenation reactions can lead the way towards sustainable and effective industrial organic catalysis.

Highly efficient visible-light-driven photocatalytic degradation of gaseous toluene by rutile-anatase TiO2@MIL-101 composite with two heterojunctions

The construction of heterophase junctions by rutile-anatase TiO2 is considered an effective strategy for toluene degradation, but the photogenerated electron utilization is still insufficient. In this study, the formation of type-II heterojunction by the encapsulation of Materials of Institut Lavoisier (MIL-101) by anatase is performed, and then the heterophase junction is further constructed to improve the catalytic performance of the photocatalyst. The enhancement of photocatalytic performance depends on the encapsulation of MIL-101 by anatase, the light absorption capacity of anatase, and the contact area of two heterojunctions. Photogenerated electrons are transferred to oxygen vacancies of anatase and promoting the generation of oxygen-containing radicals. The material certifies the synergistic effect of the heterophase junction and heterojunction design and provides a theoretical basis for application in the degradation of volatile organic compounds.

A new attempt to control volatile organic compounds (VOCs) pollution - Modification technology of biomass for adsorption of VOCs gas

The detrimental impact of volatile organic compounds on the surroundings is widely acknowledged, and effective solutions must be sought to mitigate their pollution. Adsorption treatment is a cost-effective, energy-saving, and flexible solution that has gained popularity. Biomass is an inexpensive, naturally porous material with exceptional adsorbent properties. This article examines current research on volatile organic compounds adsorption using biomass, including the composition of these compounds and the physical (van der Waals) and chemical mechanisms (Chemical bonding) by which porous materials adsorb them. Specifically, the strategic modification of the surface chemical functional groups and pore structure is explored to facilitate optimal adsorption, including pyrolysis, activation, heteroatom doping and other methods. It is worth noting that biomass adsorbents are emerging as a highly promising strategy for green treatment of volatile organic compounds pollution in the future. Overall, the findings signify that biomass modification represents a viable and competent approach for eliminating volatile organic compounds from the environment.

Tuning the Hierarchical Pore Structure and the Metal Site in a Metal-Organic Framework Derivative to Unravel the Mechanism for the Adsorption of Different Volatile Organic Compounds

Volatile organic compounds (VOCs) are one of the main classes of air pollutants, and it is important to develop efficient adsorbents to remove them from the atmosphere. To do this most efficiently, we need to understand the mechanism of VOC adsorption. In this work, we described how the metal organic framework (MOF), ZIF-8, was used as a precursor to generate MOF derivatives (Zn-GC) through temperature-controlled calcination, which had adjustable metal sites and hierarchical pore structure. It was used as a model adsorbent to study the adsorption and desorption characteristics of different VOCs. Zn-GC-850 with developed pores exhibited higher adsorption performance for the benzene series, whereas Zn-GC-650 with more metal sites had a better adsorption capacity for oxygen-containing VOCs. By tuning the molecular structure of the VOCs, we revealed the adsorption mechanism of different VOCs at the molecular level. The more developed hierarchical pore structure obtained at the higher temperature facilitates the diffusion of the benzene series, and the noncovalent interaction between their methyl group(s) and the carbonized MOF derivatives improves the adsorption affinity; while the higher exposure of Zn sites obtained at lower temperature favors the adsorption of oxygen-containing VOCs by Zn-O bonds. The mass transfers of VOCs and the role of the adsorbent were simulated by multiple theoretical models. This study strengthens the basis for the design and optimization of the adsorbent and catalyst for VOCs treatment.

Adsorption performance and kinetics of Cr(VI) onto activated carbons derived from the waste leaves of invasive plants Rhus typhina and Amorpha fruticosa

To maximize the potential of biomass from invasive plants, waste leaves from Rhus typhina (RT) and Amorpha fruticosa (AF) were used to prepare activated carbons (ACs) for the efficient removal of chromium from wastewater. Six ACs were prepared by CO2 activation at 850 °C with varying flow rates (500, 1000, and 1500 mL/min) and characterized by yield, pH, N2 adsorption isotherm, FTIR, SEM, TG, and XPS. The adsorption isotherm and kinetics for chromium removal were analyzed. The outcomes showed that the ACs had mesoporous structures with specific surface areas of 408.05-701.01 m2/g and pore volumes of 0.360-0.653 cm3/g. The pores are distributed among the agglomerated nanoparticles on the surface of the granules. The existence of two kinds of chromium compounds and two valance states, Cr(III) and Cr(VI), in spent ACs was identified by the FTIR and XPS spectra. The Cr (VI) equilibrium data and adsorption kinetics were well-fit with the Langmuir isotherm (R2 = 0.936-0.967) and pseudo-second-order kinetic models (R2 = 0.795-0.937). The maximum Langmuir Cr adsorption capacities of ACRT1.0 and ACAF0.5 were estimated to be 266.54 and 255.21 mg/g at pH = 2.0, respectively. Concentrations of Cr(III) and Cr(VI) in filtrates after equilibrium, combined with XPS and TGA analysis of spent ACs, illustrated that Cr(VI) was converted to the less harmful trivalent chromate Cr(III) during the adsorption processes. Cr(III) and Cr(VI) probably formed compounds with carbon and nitrogen atoms on the surfaces of ACs. ACs with abundant surface N-H groups achieved high Cr adsorption performance. The waste leaves from these invasive plants are suitable for producing cost-effective and efficient ACs for removing Cr (VI) from water by chemical adsorption.

Synthesis and applications of biomass-derived porous carbon materials in energy utilization and environmental remediation

Renewable biomass and its waste are considered among the most promising applications materials owing to the depletion of fossil fuel and concerns about environmental pollution. Notably, advanced porous carbon materials derived from carbon-rich biomass precursors exhibit controllable pore structures, large surface areas, natural microstructures, and abundant functional groups. In addition, these three-dimensional structures provide sufficient reaction sites and fascinating physicochemical properties that are conducive to heteroatom doping and functional modification. This review systematically summarizes the design methods and related mechanisms of biomass-derived porous carbon materials (BDPCMs), discusses how the synthesis conditions influence the structure and performance of the carbon material, and emphasizes the importance of its use in energy utilization and environmental remediation applications. Current BDPCMs challenges and future development strategies are finally discussed to provide systematic information for further synthesis and performance optimization, which are expected to lead to novel ideas for the future development of bio-based carbon materials.

Synthesis of Porous Activated Carbon Doped with Tetramethylammonium Hydroxide: Evaluation of Excellent Gasoline Vapor Adsorption Performance and Activation Mechanism

The rapid urbanization and industrialization in China have led to an urgent dilemma for controlling urban air pollution, including the intensified emission of gasoline vapor into the atmosphere. Herein, we selected highland barley straw as a raw material and KOH and tetramethylammonium hydroxide (TMAOH) as activators to synthesize nitrogen-doped layered porous carbon (K-thAC) by a three-step activation method. The obtained K-thAC materials had a high specific surface area, reaching 3119 m2/g. Dynamic adsorption experiments demonstrated a superior adsorption capacity of up to 501 mg/g (K-thAC-25) for gasoline vapor compared with other documented carbon adsorbents. Moreover, adjusting the ratio of raw materials with a series of active ingredients could further improve the pore properties of the obtained K-thACs and their adsorption performance for gasoline vapor. Furthermore, the K-thAC materials were also characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), synchronous thermogravimetry (STA), X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption tests. This study synthesized a novel plant-based material to treat gasoline vapor pollution efficiently.

Experimental and theoretical calculations insight into acetone adsorption by porous carbon at different pressures: Effects of pore structure and oxygen groups

The influence of different pore size and oxygen groups for porous carbons on acetone adsorption at different pressure was studied by using experimental data and theoretical calculation, and the results were applied to prepare carbon-based adsorbents with superior adsorption capacity. First, we successfully prepared five types of porous carbons with different gradient pore structure but similar oxygen contents (4.9 ± 0.25 at.%). We found that the acetone uptake at different pressure depends on the different pore sizes. Besides, we demonstrate how to accurately decompose the acetone adsorption isotherm into multiple sub-isotherms based on different pore sizes. Based on the isotherm decomposition method, the acetone adsorption at 18 kPa is mainly in the form of pore-filling adsorption in the pore size range of 0.6-2.0 nm. When the pore size is greater than 2 nm, the acetone uptake mainly depends on the surface area. Second, porous carbons with different oxygen content, similar surface area and pore structure were prepared to study the influence of oxygen groups on acetone adsorption. The results show that the acetone adsorption capacity is determined by the pore structure at relatively high pressure, and the oxygen groups only slightly increase the adsorption capacity. However, the oxygen groups can provide more active sites, thereby enhancing acetone adsorption at low pressure.

Precise preparation of biomass-based porous carbon with pore structure-dependent VOCs adsorption/desorption performance by bacterial pretreatment and its forming process

Pore distribution characteristic is one of the most crucial factors for porous adsorption materials, and the variety of volatile organic compounds (VOCs) approaches about how to simply and accurately tailor practical porous carbons for VOCs adsorption has gradually attracted attention. Here, precursors with different lignocellulose mass ratios have been used to produce porous carbon for model experiments to investigate the influence of the precursor lignocellulose contents on the pore structure and distribution characteristics of porous carbon, and the applicability of these mechanisms to real biomass materials has been further verified through bacteria-targeted bagasse decomposition: the microvolumes of ultra-micropores have decreased with decrease in cellulose contents, while mesopores have followed the reverse trend. The dynamic toluene adsorption/desorption performances of the obtained samples have been tested. The BACs-36 exhibits high toluene adsorption performance in low concentration with 635 mg/g while the BACs-48 shows excellent reusability in 10 times cycles. Based on this the balance between the adsorptive and regenerative capacities has been observed which indicates that carbon materials with abundant micropores and narrow mesopores have much better adsorption performance than porous carbon with a hierarchical pore structure, while the latter show better regeneration abilities than the former, which resulting in less desorption as a counter-acting force at the pore wall. Furthermore, the porous carbon has been shaped by one-step co-pyrolysis method using phenolic resin, which can not only maintain the hardness but also can avoid pore plugging phenomenon.

Synthesis of hierarchical porous carbon with high surface area by chemical activation of (NH4)2C2O4 modified hydrochar for chlorobenzene adsorption

In this work, hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH₄)₂C₂O₄ as a novel nitrogen-doping agent. Physicochemical properties of NPCK-x were characterized by Brunauer-Emmett-Teller, field emission scanning electron microscopy, X-ray diffraction, Raman microscope, elemental analysis, and X-ray photoelectron spectroscopy. Results showed that the NPCK-x samples possessed large surface areas (maximum: 2875 m²/g), hierarchical porous structures, and high degree of disorder. N-containing functional groups decomposed during activation process, which could be the dominant reason for appearance of abundant mesopores and well-developed pore structure. Dynamic chlorobenzene adsorption experiments demonstrated that carbon materials with (NH₄)₂C₂O₄ modification exhibited higher adsorption capacity (maximum: 1053 mg/g) than those without modification (maximum: 723 mg/g). The reusability studies of chlorobenzene indicated that the desorption efficiency of (NH₄)₂C₂O₄ modified porous carbon reached 90.40% after thermal desorption at 100°C under N₂ atmosphere. Thomas model fitting results exhibited that the existence of mesopores accelerated the diffusion rate of chlorobenzene in porous carbon. Moreover, Grand Canonical Monte Carlo simulation was conducted to verify that micropores with pore sizes of 1.2-2 nm of the optimized porous carbon were the best adsorption sites for chlorobenzene and mesopores with pore sizes of 2-5 nm were also highly active sites for chlorobenzene adsorption.

Revealing the Pore Size-Dependent Sorption Mechanism of Toluene and Cetane in Porous Carbon by Nuclear Magnetic Resonance

The adsorption of contaminants by porous carbon has been extensively studied by conventional isotherm and kinetic methods. However, the co-adsorption behavior and sorption sites of multiple contaminants in different-sized pores remain unclear. Herein, the nuclear magnetic resonance (NMR) approach is performed to investigate the adsorption mechanism of toluene and cetane in the confined space of carbon at the molecular level. The ring current effect induces the variation in the NMR chemical shifts of in-pore adsorbed toluene and cetane, realizing the identification of pore-dependent adsorption sites for contaminant removal. Cetane has a slower adsorption kinetic but a higher binding energy than toluene, which could squeeze toluene from micropores to larger pores with increasing adsorption quantity. This leads to a stronger competitive adsorption effect in small micropores than in mesopores. Accordingly, hierarchical porous carbons are determined to be the most effective adsorbents for the adsorption of coexisting contaminants. This study not only provides an effective NMR method to reveal the adsorption mechanism in the confined space of porous carbon at the molecular level but also offers new insights into the pore size-dependent adsorption of activated carbon for petroleum contaminant treatment.

Adsorption and membrane separation for removal and recovery of volatile organic compounds

Volatile organic compounds (VOCs) are a crucial kind of pollutants in the environment due to their obvious features of severe toxicity, high volatility, and poor degradability. It is particularly urgent to control the emission of VOCs due to the persistent increase of concentration and the stringent regulations. In China, clear directions and requirements for reduction of VOCs have been given in the "national plan on environmental improvement for the 13th Five-Year Plan period". Therefore, the development of efficient technologies for removal and recovery of VOCs is of great significance. Recovery technologies are favored by researchers due to their advantages in both recycling VOCs and reducing carbon emissions. Among them, adsorption and membrane separation processes have been extensively studied due to their remarkable industrial prospects. This overview was to provide an up-to-date progress of adsorption and membrane separation for removal and recovery of VOCs. Firstly, adsorption and membrane separation were found to be the research hotspots through bibliometric analysis. Then, a comprehensive understanding of their mechanisms, factors, and current application statuses was discussed. Finally, the challenges and perspectives in this emerging field were briefly highlighted.

Evaluation of Biological Pretreatment of Wormwood Rod Reies with White Rot Fungi for Preparation of Porous Carbon

In this work, the wormwood rod residues are pretreated with white rot fungi as the precursor to preparing porous carbon following a simple carbonization and activation process (denoted herein as FWRA sample). The FWRA sample possesses abundant hierarchical pores structure with high specific surface area (1165.7 m² g^-1) and large pore volume (1.02 cm³ g^-1). As an electrode for supercapacitors, the FWRA sample offers a high specific capacitance of 443.2 F g^-1 at 0.5 A g^-1 and superb rate ability holding a specific capacitance of 270 F g^-1 at 100 A g^-1 in 6 M KOH electrolyte. The corresponding symmetrical capacitor has a superb cyclic stability with a low specific capacitance decay rate of 0.4% after 20,000 cycles at 5 A g^-1 in 1 M Na₂SO₄ electrolyte. Moreover, measurements revealed that when used as adsorbent, the FWRA sample is ideal for removing methyl orange (MO) from water, exhibiting a superior adsorption ability of 260.8 mg g^-1. Therefore, this study is expected to provide a simple and environmentally friendly technique for the generation of value-added and functional porous carbon materials from Chinese medicinal herbal residues, thus offering promising candidates for broad application areas.

Facile Synthesis of NiO-CuO/Activated Carbon Nanocomposites for Use in the Removal of Lead and Cadmium Ions from Water

In this work, activated carbon (AC) was synthesized and then modified using nickel(II) oxide and copper(II) oxide. Pure-AC, 10, 20, 30, and 40 wt % nanohybrid NiO-CuO/AC nanocomposites (χ-NC/AC NCs) were characterized using XRD, IR, EDS, surface area, and FE-SEM techniques. Furthermore, the adsorbents obtained were tested for their ability to remove hazardous Pb(II) and Cd(II) from water. The fabricated x-NC/AC NC adsorbents showed the highest adsorptive performance toward the adsorption of Pb(II) and Cd(II) from water. The 30-NC/AC NC adsorbent showed the complete removal of Pb(II) at pH = 5 and Cd(II) at pH = 7 within 30 min. Overall, the obtained superior experimental results suggest that the adsorptive performance of AC was greatly enhanced after loading hybrid metal oxide nanoparticles, so its application in water treatment is potential and applicable.

New insights into hierarchical pore size and level of concentration in efficient removal of toluene vapor by activated carbon

The hierarchical pore structure of nanoporous carbon and gaseous toluene concentration co-mediated adsorption mechanism was examined. The KOH-activated carbons with tailorable high surface area (1126-3148 m²/g), large pore volume (0.446-2.08 cm³/g) and broadening average pore width (0.873-2.68 nm) were prepared. Dynamic adsorption was used to determine breakthrough curves and adsorption isotherms of toluene by as-prepared KOH-activated carbons and commercial activated carbons. The experimental results showed that the breakthrough time is positively correlated with ultramicropore volume of all activated carbons. The equilibrium amounts adsorbed (q_e) for toluene at 100 ppmv were as high as 454 mg/g on KOH-activated carbons. The q_e for toluene at P/P₀ < 0.017 dominated by ultramicropore volume of all activated carbons were attributed to the enhanced superposition of adsorption force field between adjacent ultramicropore walls. A large adsorption affinity is imperative to achieve high amounts adsorbed for toluene at low concentration. The toluene was firstly filled in ultramicropores then gradually occupied in wide micropores at 0.017 <P/P₀ < 0.1 and the q_e were linearly correlated with micropore volume. The q_e of toluene at P/P₀ > 0.1 were linearly correlated with volume of micropore and small mesopore. The governing porosity in adsorbing toluene is varied with the intruding concentration. These results provided new insights into adsorption mechanism and development of novel materials.

Advances in Micro-/Mesopore Regulation Methods for Plant-Derived Carbon Materials

In recent years, renewable and clean energy has become increasingly important due to energy shortage and environmental pollution. Selecting plants as the carbon precursors to replace costly non-renewable energy sources causing severe pollution is a good choice. In addition, owing to their diverse microstructure and the rich chemical composition, plant-based carbon materials are widely used in many fields. However, some of the plant-based carbon materials have the disadvantage of possessing a large percentage of macroporosity, limiting their functionality. In this paper, we first introduce two characteristics of plant-derived carbon materials: diverse microstructure and rich chemical composition. Then, we propose improvement measures to cope with a high proportion of macropores of plant-derived carbon materials. Emphatically, size regulation methods are summarized for micropores (KOH activation, foam activation, physical activation, freezing treatment, and fungal treatment) and mesopores (H3PO4 activation, enzymolysis, molten salt activation, and template method). Their advantages and disadvantages are also compared and analyzed. Finally, the paper makes suggestions on the pore structure improvement of plant-derived carbon materials.

A high-performance and stable Cu/Beta for adsorption-catalytic oxidation in-situ destruction of low concentration toluene

Finding a cost-effective treatment to remove of low concentrations of volatile organic compounds (VOCs) is still a challenge. In this study, a Cu/Beta material was developed for in situ adsorption-catalytic oxidation of low concentrations of toluene. The results showed that the addition of Cu enhanced the adsorption and catalytic oxidation of toluene by Beta zeolite. Cu7/Beta with a Cu⁺ ratio of close to 50% performed best. The high adsorption of Cu7/Beta was mainly attributed to the abundant Cu⁺ species and the micro-mesoporous structure of the Beta zeolite, and the high catalytic oxidation was attributed to the lattice oxygen in the uniformly dispersed CuO. Finally, the adsorption intermediates and reaction pathways in the catalytic oxidation of toluene were clarified using XPS and DRIFTS spectra. This work provides new strategies for the development of efficient and stable adsorption-catalytic oxidation in situ destruction materials.

Perfluorinated conjugated microporous polymer for targeted capture of Ag(I) from contaminated water

The maximum targeted capture silver from contaminated water is urgently necessary for sustainable development. Herein, the perfluorination conjugated microporous polymer adsorbent (F-CMP) has been fabricated by Sonogashira-Hagihara coupling reaction and employed to remove Ag(I) ions. Characterizations of NMR, XPS and FT-IR indicate the successful synthesis of F-CMP adsorbent. The influence factors of F-CMP on Ag(I) adsorption behavior are studied, and the adsorption capacity of Ag(I) reaches 251.3 mg/g. The experimental results of isothermal adsorption and kinetic adsorption are consistent with the Freundlich model and pseudo-second-order isothermal adsorption model, which follows a multilayer adsorption behavior on the uniform surface of the adsorbent, and the chemical adsorption becomes the main rate-limiting step. Combined with DFT calculation, the adsorption mechanism of Ag(I) by F-CMP is elucidated. The peaks shift of sp before and after adsorption is larger than that of F1s, suggesting that the -CC- on the F-CMP becomes the dominant chelation site of Ag(I). Furthermore, F-CMP exhibits specific adsorption for Ag(I) in polymetallic complex water, with the maximum selectivity coefficient of 31.5. Our study may provide a new possibility of perfluorinated CMPs for effective capture of Ag(I) ions to address environmental issues.

Preparing hierarchical porous carbon with well-developed microporosity using alkali metal-catalyzed hydrothermal carbonization for VOCs adsorption

Biomass-derived porous carbonaceous materials are efficient adsorbents for VOCs, but their traditional preparation method, pyrolysis combined with activation, suffers from high energy consumption, equipment corrosion, and low pore-making efficiency, which hinders their large-scale practical application. A novel method of alkali metal-catalyzed hydrothermal carbonization coupling with chemical activation for the preparation of microporous carbon is presented. Porous carbon with well-developed microporosity deriving from corn husk were prepared through the hydrothermal carbonization using potassium persulfate (K₂S₂O₈) as a catalyst and programmed heating activation process. And the products were applied to removal of typical oxygen-containing VOCs, ethyl acetate. The addition of K₂S₂O₈ in hydrothermal carbonization accelerated the biomass hydrolysis, decomposed the biopolymer, and formed functional hydrochars. Potassium salts introduced into the hydrochars, which acted as an activator in this programmed heating activation process, formed a great deal of micropores. The specific surface area of micropores increased by 81%, and the specific surface area of micropores less than 1 nm increased by 180%. The introduction of K₂S₂O₈ in preparation improved the adsorption performance of CH-based porous carbons 16.46% and 60.00% respectively at different preparation temperatures (600 °C and 800 °C). Basing on these results, the improvement of micropores less than 1 nm is directly related to the adsorption performance. This indicates that pores (<1 nm) respond well to the adsorption of ethyl acetate.

Role of molecular size of volatile organic compounds on their adsorption by KOH-activated micro-mesoporous carbon

KOH-activated carbon (KAC) with high surface area and abundant micropores are widely used in adsorbing volatile organic compounds (VOCs). Kinetic diameters (σ) of VOCs are an important factor controlling diffusion of VOCs into pores of adsorbent. Yet the influence of kinetic diameters of VOCs on their adsorption by KAC remains unclear. Here, we investigated the dynamic adsorption of VOCs with various kinetic diameters on a prepared KAC with high surface area of 3100 m²/g, pore volume of 2.08 cm³/g and average pore width (D) of 2.68 nm. Adsorption affinity was negatively correlated with size difference (D-σ), indicating that pore width of adsorbent should close to σ to obtain a strong interaction between VOCs and adsorbents. Amounts adsorbed were positively correlated with σ at low relative pressures (p/p₀ < 0.01), and negatively correlated with σ at high relative pressures (p/p₀ > 0.044). The above results suggest that larger molecules with higher affinities are preferentially adsorbed at low relative pressures, amounts adsorbed of smaller molecules are larger than that of bigger molecules at high relative pressures. This study provided new insights into adsorption mechanisms mediated by σ and the development of next generation adsorbents for efficient removal of VOCs.

Key factors and primary modification methods of activated carbon and their application in adsorption of carbon-based gases: A review

To achieve carbon neutrality, it is necessary to control carbon-based gas emissions to the atmosphere. Among the various carbon-based gas removal technologies reported to date, adsorption is considered one of the most promising because of its economic efficiency, reusability, and low energy consumption. Activated carbon is widely used to treat different types of carbon-based gases owing to its large specific surface area, abundant functional groups, and strong adsorption capacity. This paper reviews the recent research progress into activated carbon as an adsorbent for carbon-based gases. The key factors (i.e., specific surface area, pore structure, and surface functional groups) affecting the adsorption of carbon-based gases by activated carbon were analyzed. The main methods employed to modify activated carbon (i.e., surface oxidation, surface reduction, loading materials, and plasma modification methods) to improve its adsorption capacity are also discussed herein, along with the targeted applications of such material in the adsorption of different types of carbon-based gases (such as aldehydes, ketones, aromatic hydrocarbons, halogenated hydrocarbons, and carbon-based greenhouse gases). Finally, the future development directions and challenges of activated carbon are discussed. Our work will be expected to benefit the development of activated carbon exhibiting selective adsorption properties, and reduce the production costs of adsorbents.

Functionalized Activated Carbon for Competing Adsorption of Volatile Organic Compounds and Water

The interfacial interaction of activated carbon with volatile organic compounds (VOCs) is seriously affected by water vapor. Therefore, it is vital to enhance the hydrophobic performance of activated carbon for expanding its application in industrial and environmental fields. Herein, a series of hydrophobic activated carbon was fabricated by tailored mixed siloxane and applied in dynamic competitive adsorption at 0, 50, and 90% humidity. Simultaneously, the diffusion molecular models and multicomponent adsorption experiments were used to study the adsorption and diffusion mechanisms. The hydrophobicity of activated carbon was significantly improved by loading of mixed siloxane, in which the equilibrium water absorption decreased from 21.9 to 7.2% and the contact angles increased by 70.10°. Meanwhile, dynamic competitive adsorption at different humidities indicated that the siloxane-functionalized activated carbons (SACs) showed much better competitive adsorption performances for VOCs than original activated carbon, which was further confirmed by the theoretical calculations of adsorption energy. In addition, a remarkable adsorption selectivity and reusability could be demonstrated to VOCs with different polarities on SACs. This study not only provides a new strategy for the hydrophobic modification of activated carbon materials but also offers theoretical guidance for the treatment of gas streams with significant water contents.

Triple combination of natural microbial action, etching, and gas foaming to synthesize hierarchical porous carbon for efficient adsorption of VOCs

Fungi residue, vinasse, and biogas residue differ from general biomass waste due to natural microbial action. Microbial fermentation helps create natural channels for the permeation of activators and produces proteins for natural nitrogen doping. Inspired by these advantages on porous carbon synthesis, this study adopted dual activators of KOH and KHCO₃ to synthesize porous carbon with different pore ratios for efficient adsorption of volatile organic compounds (VOCs). The fungi residue possessed the least lignin due to the most severe microbial action, contributing to the best pore structures after activation. The etching effect from potassium compounds and gas foaming from the carbonate decomposition contributed to creating hierarchical porous carbon with ultra-high surface area, ca. 1536.8-2326.5 m²/g. However, KHCO₃ addition also caused nitrogen erosion, such that lower adsorption capacity was attained even with a higher surface area when the mass ratio of KOH/KHCO₃ decreased from 2.5:0.5 to 2:1. The maximum adsorption capacities of chlorobenzene (CB) and benzene (PhH) reached 594.0 and 394.3 mg/g, respectively. Pore structure variations after adsorption were evaluated by freeze treatment to discover the adsorption mechanism. The surface area after CB and PhH adsorption decreased 40.3% and 34.5%, respectively. Most of the mesopores might transform into micropores due to the mono/multilayer stacking of adsorbates. The VOC adsorption kinetics were simulated by the Pseudo-first- and -second-order models and Y-N model. This paper provides a new approach for high-value biomass waste utilization after microbial action to synthesize efficient adsorbents for VOCs.

Integrated approach in treatment of solid olive residue and olive wastewater

Generally olive oil generated two forms of waste by-products: solid olive residue (SOR) and olive wastewater (OWW). In the present study a promising solution is given to treat both SOR and OWW waste by-products. The first process consists of converting the solid olive residue to activated carbon using pyrolysis process at 600 °C, followed by steam activation procedure at three different temperatures. The attained activated carbon was examined by different experimental techniques such as FTIR, SEM, BET and iodine number. The surface area was increased by increasing stream activation temperature (reach 1020 m2 g−1 BET). However, the steam activation at 700 °C was found to be ideal for environmental and economic performance. On the other hand, the activated carbon at 700 °C displayed high removal capacity of both polyphenolic compounds and COD from olive wastewater. In fact, after 2 h of treatment, 95.5% of COD and 84.2% of polyphenolic compounds were completely removed.

Fe-based metal organic framework derivative with enhanced Lewis acidity and hierarchical pores for excellent adsorption of oxygenated volatile organic compounds

A series of Fe-based metal organic framework derived materials were prepared by thermal treating MIL-100(Fe) in nitrogen atmosphere for adsorption removal of oxygenated volatile organic compounds (OVOCs) such as methanol, formaldehyde and acetone under dynamic conditions. The experimental results showed that the partially carbonized M-350 material obtained by calcining MIL-100(Fe) at 350 °C exhibited the best adsorption performance and high stability. The breakthrough adsorption capacity of M-350 for methanol was 61.5% higher than that of pure MIL-100 (Fe), and it was 24.7, 6.5 and 2.6 times higher than that of commercial activated carbon, ZSM-5 and SAPO-34 adsorbents, respectively. The excellent adsorption performance was attributed to the exposure of abundant coordinatively unsaturated iron metal sites acting as Lewis acid sites through high temperature calcination, which had a strong affinity for OVOCs. Meanwhile, a hierarchical porous structure and high specific surface area further promoted the adsorption. This work provides new insights into the further development of metal organic frameworks based functional materials for VOCs removal and purification.

Quantitative Coassembly for Precise Synthesis of Mesoporous Nanospheres with Pore Structure-Dependent Catalytic Performance

Precise synthesis of porous materials is essential for their applications. Self-assembly is a widely used strategy for synthesizing porous materials, but quantitative control of the assembly process still remains a great challenge. Here, a quantitative coassembly approach is developed for synthesizing resin/silica composite and its derived porous spheres. The assembly behaviors of the carbon and silica precursors are regulated without surfactants and the growth kinetics of the composite spheres are quantitatively controlled. This assembly approach enables the precise control of the size and pore structures of the derived carbon spheres. These carbon spheres provide a good platform to explore the structure-performance relationships of porous materials, and demonstrate their pore structure-dependent performance in catalytic water decontamination. This work provides a simple and robust approach for precise synthesis of porous spheres and brings insights into function-oriented design of porous materials.

Lignin-based adsorbent-catalyst with high capacity and stability for polychlorinated aromatics removal

The utilization of lignin as carbonaceous material for pollution adsorption provides an alternative way for lignocellulose valorization. Here in, lignin-based adsorbents (i.e., LC-A, LC-B, and LC-C) were prepared and used for the removal of o-DCB (a toxic gaseous pollutant). LC-B exhibited the best adsorption capacity (718.2 mg/g) when comparing with LC-A (93.1 mg/g), LC-C (10.2 mg/g), and activated carbon (72.7 mg/g). LC-B also demonstrated excellent recycling stability with the adsorption capacity of 710.8 mg/g after five runs. More importantly, LC-B supported Ru adsorbent catalyst could effectively remove o-DCB with removal rate >80% under a wide range of temperature (50-300°C). The excellent performance of lignin-based adsorbents could be attributed to its abundant pore structure, high specific surface area (1618.55 m²/g), enhanced graphitization degree as well as the abundant hydroxyl functional groups. The present work provided a cost-effective strategy for pollution control by lignin-based material.

Mechanistic insights into and modeling the effects of relative humidity on low-concentration VOCs adsorption on hyper-cross-linked polymeric resin by inverse gas chromatography

Water vapor is very common in contaminated streams, which has a great influence on the adsorption of low-concentration volatile organic compounds (VOCs) due to the competition between water and VOCs. Understanding adsorption mechanisms and predicting adsorption of VOCs under different relative humidity (RH) are of great importance to design effective adsorption unit. In this study, we comprehensively investigated the effects of RH on the surface properties of hyper-cross-linked polymeric resin (HPR) and adsorption of 18 VOCs at low concentration on HPR under five levels of RH using inverse gas chromatography (IGC). Further, a promising RH-dependent poly-parameter linear free energy relationships (PP-LFERs) model was developed. It was found that water vapor caused the decrease of surface free energy (γ_s^t) of HPR due to the occupation of active sites by water molecules, resulting in the decrease of adsorption partition coefficients (K). Moreover, the γ_s^t could accurately quantify the effects of RH on the surface properties of HPR. Therefore, the RH-dependent PP-LFERs model was established by correlating RH and γ_s^t. The developed model overcame the limited predictive ability of existing models only under a specific RH level, and excellently predicted the lnK values of VOCs (R² = 0.944, RMSEt = 0.36 and RMSEv = 0.47) under various RH.

Preparation of porous carbon based on partially degraded raw biomass by Trichoderma viride to optimize its toluene adsorption performance

Volatile organic compounds (VOCs), which are usually organic compounds with boiling point in the range of 50 to 260°C, pose a serious threat to human health and ecological environment. In order to find an adsorbent with excellent adsorption effect on VOCs, activated carbon was prepared from corn bran partially degraded by Trichoderma viride, and the adsorption performance of the optimized porous carbon materials on toluene was studied. Physical and chemical properties (such as specific surface area, pore size distribution, and surface functional groups) of the activated carbon were characterized by scanning electron microscope (SEM), N₂ adsorption/desorption experiences, Fourier-transform infrared (FTIR), and Raman and X-ray diffraction (XRD). The results showed that the specific surface area of corn bran reached 1896 m²/g and the total pore volume was 1.04 cm³/g after 15 days of microbial pretreatment. Dynamic simulation of adsorption experiment found that the saturated adsorption capacity of the pretreated carbon material was 237 mg/g at 100 ppm toluene concentration, which was 1.58 times of that of corn bran without microbial pretreatment. Generally, the improvement of adsorption performance may be mainly attributed to the increase of specific surface area, pore volume and the decrease of surface acidic groups.

Hierarchical porous biochar from plant-based biomass through selectively removing lignin carbon from biochar for enhanced removal of toluene

This study proposed a simple and green air oxidation (AO) method to prepare hierarchical porous biochar by selectively removing lignin carbon from biochar after the pyrolysis of plant-based biomass, based on the fact that the thermal decomposition temperature in air between lignin carbon and cellulose/hemicellulose carbon was different. Three kinds of biomass with different lignocellulose contents were used, including walnut shell, cypress sawdust and rice straw. The results found that AO treatment could effectively improve the pore structure of the three biochar. The specific surface area of WCO-4, CCO-4 and RCO-4 was 555.0 m²/g, 418.7 m²/g and 291.9 m²/g, respectively, which was significantly higher than those of WC (319.5 m²/g), CC (381.7 m²/g) and RC (69.6 m²/g), respectively. Among these, walnut shell biochar with air oxidation (WCO) had higher surface area of 555.0 m²/g and mesopore volume of 0.116 cm³/g, this was related to its high content of lignin, which could facilitate the formation of mesopores by AO treatment with high selectivity. The toluene adsorption capacity of WCO reached 132.9 mg/g, which increased by 223.4% from that without AO treatment. The kinetics study indicated that the diffusion rates of toluene molecule were improved due to the increased mesopores volume of biochar and micropores also play an important role in the adsorption of toluene. The results demonstrate that AO treatment is a promising method to develop hierarchical porous structure for lignocellulose-rich plant-based biomass with low cost and environmental-friendly, which greatly enhanced the toluene adsorption capacity.

Recent Progress in Metal-Organic Framework-Derived Nanostructures in the Removal of Volatile Organic Compounds

Air is the most crucial and life-supporting input from nature to the living beings of the planet. The composition and quality of air significantly affects human health, either directly or indirectly. The presence of some industrially released gases, small particles of anthropogenic origin, and the deviation from the normal composition of air from the natural condition causes air pollution. Volatile organic compounds (VOCs) are common contaminants found as indoor as well as outdoor pollutants. Such pollutants represent acute or chronic health hazards to the human physiological system. In the environment, such polluted gases may cause chemical or photochemical smog, leading to detrimental effects such as acid rain, global warming, and environmental pollution through different routes. Ultimately, this will propagate into the food web and affect the ecosystem. In this context, the efficient removal of volatile organic compounds (VOCs) from the environment remains a major threat globally, yet satisfactory strategies and auxiliary materials are far from being in place. Metal–organic frameworks (MOFs) are known as an advanced class of porous coordination polymers, a smart material constructed from the covalently bonded and highly ordered arrangements of metal nodes and polyfunctional organic linkers with an organic–inorganic hybrid nature, high porosities and surface areas, abundant metal/organic species, large pore volumes, and elegant tunability of structures and compositions, making them ideal candidates for the removal of unwanted VOCs from air. This review summarizes the fundamentals of MOFs and VOCs with recent research progress on MOF-derived nanostructures/porous materials and their composites for the efficient removal of VOCs in the air, the remaining challenges, and some prospective for future efforts.

Highly efficient adsorptive removal of toluene using silicon-modified activated carbon with improved fire resistance

Activated carbons (ACs) are widely applied in the removal of volatile organic compounds (VOCs) emitted from industrial processes, because of their high adsorption capacity, low cost and reusability. Their poor thermal stability under oxidative conditions is a limiting factor and often leads to fire risk in real applications. Here, Si-modification was performed over a wood-derived AC material, and a series of modified ACs with different Si/C mass ratios (0.1-0.9) were prepared via a hydrothermal route. Physicochemical characteristics of Si/C samples was examined by XRD, SEM, TEM, XPS, FTIR and N₂-physisorption measurements. As compared to pristine AC, Si-modified ACs showed enhanced fire resistance, and an increase of ignition temperature by 79 ℃ was achieved at a Si/C mass ratio of 0.9. A combination of TEM, XPS and FTIR characterization suggests that the formation of amorphous SiO₂ nanoparticles and SiC species on the surface was responsible for the enhanced fire resistance of Si-modified ACs. By increasing microporosity, Si-modification also significantly improved the adsorption capacity of toluene as a model VOC molecule. Static and dynamic adsorption experiments were performed to understand the adsorption kinetics of the Si-modified ACs. Reusability tests showed that the desorption rate of the modified AC remained at nearly 80% even after five cycles of repeated adsorption-desorption, indicating that the modified AC has a great potential for industrial applications.