Montmorillonite restricts free fatty acid liberation and alters self-assembled structures formed during in vitro lipid digestion.

The global rise in obesity necessitates innovative weight loss strategies. Naturally occurring smectite clays, such as montmorillonite (MMT), offer promise due to their unique properties that interfere with free fatty acid (FFA) liberation, reducing systemic uptake. However, the mechanisms of MMT-FFA interactions and their implications for weight management are undefined. This study investigates these interactions by adding MMT (10 % w/w) to in vitro lipolysis media containing medium chain triglycerides (MCTs), and monitoring FFA liberation using pH-stat titration. Nanoparticle tracking analysis (NTA) and synchrotron-based small-angle X-ray scattering (sSAXS) observed time-dependent structural changes, while electron microscopy examined clay morphology during digestion. A 35 % reduction in FFA liberation occurred after 25 min of digestion with MCT + MMT, with digestion kinetics following a biphasic model driven by calcium soap formation. NTA revealed a 17-fold decrease in vesicular structures with MCT + MMT, and sSAXS highlighted a rapid lamellar phase evolution linked to calcium soap formation. This acceleration is attributed to MMT's adsorption to unionized FFAs via hydrogen bonding, supported by TEM images showing a decrease in d-spacing, indicating FFA intercalation is not the main adsorption mechanism. These findings highlight MMT's potential as a novel intervention for reducing dietary lipid absorption in obesity and metabolic diseases.

Production of activated carbon from spent coffee grounds (SCG) for removal of hexavalent chromium from synthetic wastewater solutions.

In this research, spent coffee grounds (SCG) are converted into a highly valuable porous adsorbent which removes chromium (VI) from wastewater with high efficiency. A set of nine Spent Coffee Ground Activated Carbon (SCG-AC) adsorbent samples were synthesized, by varying key parameters including pyrolysis temperature (400, 600 °C), pyrolysis duration (1 and 2 h), and the impregnation ratio of the activating agent, KOH (ranging from 0:1 to 2:1). Characterizations of these adsorbent samples were conducted by advanced analytical tools including SEM, EDX, XRD, FTIR, TGA, and BET. Furthermore, we carried out adsorption studies, exploring the effects of temperature and dosage variations. Additionally, point zero charge experiments and desorption studies were carried out to further understand the adsorption process. The outcomes of our investigation demonstrate the successful synthesis of these spent coffee ground-derived adsorbents, with a yield of up to 34%. Notably, these adsorbents exhibited high efficiency in extracting chromium (VI) from water, with removal efficiencies ranging from 75% to 100%. The adsorption isotherms revealed the Langmuir model to be the most fitting descriptor of the adsorption behavior. Moreover, a thermodynamics study revealed the process to be endothermic in nature which furthers our understanding of the underlying mechanisms. Importantly, our cost assessment shows the economic advantage of the synthesized adsorbent over commercial counterparts such as zeolite, making it a competitive choice for real-world applications. In summation, the study not only introduces an innovative and sustainable utilization of spent coffee grounds but also delivers an in-depth exploration of the synthesized adsorbent's ability in chromium (VI) removal. Our holistic approach, encompassing thorough experimentation, characterization, and economic evaluation, solidifies the significance of this research in tackling environmental concerns and propelling advancements in wastewater treatment methodologies.

Nutrients recovery from livestock wastewater by batch and gas bubble-column studies with biochar, nano-composite material, and ammonium magnesium phosphate hydrate.

The breeding of livestock raises substantial environmental concerns, especially the efficient management of nutrients and pollution. This research is designed to assess the potency of char and modified char in diluting nutrient concentrations in livestock wastewater. The characteristics of graphene oxide, struvite, and calcium-modified char were inspected, defining their efficacy in both batch and bed-column investigations of nutrient sorption. Various factors, including sorption capacity, time of contact, ion levels, a decrease in ion levels over time, and sorption kinetics, have been considered, along with their appropriateness for respective models. The first evaluation of the options concluded that 600 °C char was better since it exhibited higher removal efficiency. Modified char sorption data at 600 °C was used to adjust the models "PSOM, Langmuir", and "Thomas". The models were applied to both batch and bed-column experiments. The maximum phosphate sorption was 110.8 mg/g, 85.73 mg/g, and 82.46 mg/g for B-GO, B-S, and B-C modified chars respectively, in the batch experiments. The highest phosphate sorption in column experiments, at a flow rate of 400 µl/min, was 51.23 mg per 10 g of sorbent. This corresponds to a sorption rate of 5.123 mg/g. B-GO and B-S modified chars showed higher sorption capacities; this was observed in both the batch and bed-column studies. This displayed the capability of graphene oxide and struvite-modified chars for efficient ion and nutrient uptake, whether in single or multi-ion environments, making them a very good candidate for nutrient filtration in livestock wastewater treatment. Additionally, B-GO char enhanced the sorption of phosphate, resulting in augmented seed germination and seedling growth. These results reveal that B-GO char can be used as a possible substitute for chemical fertilizers.

Covalent organic framework-functionalized magnetic MXene nanocomposite for efficient pre-concentration and detection of organophosphorus and organochlorine pesticides in tea samples before gas chromatography-triple quadrupole mass spectrometry analysis.

In this study, a hydrophobic covalent organic framework-functionalized magnetic composite (CoFe2O4@Ti3C2@TAPB-TFTA) with a high specific area with 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 2,3,5,6-tetrafluoroterephthalaldehyde (TFTA) was designed and synthesized through Schiff base reaction. An efficient magnetic solid-phase extraction method was established and combined with gas chromatography-triple quadrupole mass spectrometry to sensitively determine 10 organochlorine and organophosphorus pesticides in tea samples. The established method exhibited good linearity in the range of 0.05-120 µg/L and had low limits of detection (0.013-0.018 µg/L). The method was evaluated with tea samples, and the spiked recoveries of pesticides in different tea samples reached satisfactory values of 85.7-96.8%. Moreover, the adsorption of pesticides was spontaneous and followed Redlich-Peterson isotherm and pseudo-second-order kinetic models. These results demonstrate the sensitivity, effectiveness, and reliability of the proposed method for monitoring organochlorine and organophosphorus pesticides in tea samples, providing a preliminary basis for researchers to reasonably design adsorbents for the efficient extraction of pesticides.

Optimizing acid microemulsions for cleaner gas production: A study on enhanced adsorption characteristics and implications in retardation.

The ultralow interfacial tension between the oil and aqueous phases and the solubilization characteristics in microemulsion systems make them useful for surface cleaning and enhanced oil recovery applications. Microemulsions can form an adsorbed barrier on rock, reducing the acid-rock reaction rate. However, as acid retardation additives, the adsorption patterns of microemulsions are not clearly defined. In this study, microemulsions composed of various electrical surfactants, oil cores, and oil core additives were obtained, and their phase behaviors were investigated. Through adsorption and reaction experiments, cleaning microemulsions that enhance adsorption effects were identified, and their adsorption patterns and adaptability under flow conditions were evaluated. The results demonstrate that incorporating negatively charged polar compounds forms an enhanced adsorption microemulsion characterized by an average droplet size of less than 30 nm after mixing with the acid. The introduction of negatively charged polar compounds resulted in a 177 % increase in adsorption and an 81 % improvement in static retardation effect. Dynamic adsorption tests indicate that the pseudo-second-order model more accurately describes the kinetics of dynamic adsorption of microemulsions on rock surfaces. Under a fixed flow rate, the dynamic retardation rate increased with the concentration of the microemulsion. In practical acidification, the adsorption of microemulsions results mainly from combined electrostatic forces and fluid scouring, characterized by a continuous process of adsorption and desorption. Scanning electron microscope also confirmed that microemulsions can form an adsorptive film on the rock, reducing the acid-rock reaction rate. This study offers practical guidelines for the selection and application of retardation additives, aiming to enhance the ecological compatibility of chemical treatments in low-permeability limestone reservoirs.

Vapor-phase transport of per and polyfluoroalkyl substances: Processes, modeling, and implications.

An increasing number of studies have demonstrated the presence of per and polyfluoroalkyl substances (PFAS) in the vapor phase. It is therefore important to consider the potential for vapor-phase transport of PFAS in soil and the vadose zone and to investigate the processes impacting the retention and transport of volatile PFAS in soil. It is also critically important to evaluate existing models and develop new models as needed for their application to PFAS vapor-phase transport. The objectives of the present work were to provide an overview of vapor-phase transport processes and modeling, with a specific focus on their relevance for PFAS, and to discuss implications for mass discharge to groundwater, vapor intrusion, and soil vapor extraction. Decades of research have been devoted to the retention and transport of legacy volatile organic contaminants in the vadose zone. This work provides an abundant source of information concerning the many factors and processes of relevance, and insights into the development and application of mathematical modeling. However, given the unique properties of PFAS, there is a need to conduct research to investigate vapor-phase transport of PFAS and to develop PFAS-specific models. We highlight with illustrative examples that vapor-phase transport can be significantly more rapid than aqueous-phase advective transport, which can result in enhanced mass discharge to groundwater.

Fabrication of cobalt-iron Prussian blue analogs functionalized hybrid membranes for efficiently capturing Tl from water: performance and mechanism.

As trace levels of thallium (Tl) in water are lethal to humans and ecosystems, it is essential to exploit advanced technologies for efficient Tl removal. In response to this concern, an innovative composite membrane was developed, incorporating polytetrafluoroethylene (PTFE) and featuring a dual-support system with polydopamine (PDA) and polyethyleneimine (PEI), along with bimetallic Prussian blue analogues (Co@Fe-PBAs) as co-supports. The composite membrane exhibited an exceptional Tl+-adsorption capacity (qm) of 186.1 mg·g-1 when utilized for the treatment of water containing low concentration of Tl+ (0.5 mg⋅L-1). Transmission electron microscopy displayed the obvious Tl+ mapping inside the special hollow Co@Fe-PBAs crystals, demonstrating the deep intercalation of Tl+ via ion exchange and diffusion. The Tl+-adsorption capability of the composite membrane was not greatly affected by coexisting Na+, Ca2+ and Mg2+ as well as the tricky K+, indicating the excellent anti-interference. Co-doped PBAs enhanced ion exchange and intercalation of the composite membrane with Tl+ leading to excellent Tl+ removal efficiency. The composite membrane could efficiently remove Tl+ from thallium- contaminated river water to meet the USEPA standard. This study provides a cost-effective membrane-based solution for efficient Tl+ removal from Tl+-containing wastewater.

Modulating Hydrogen Adsorption by Unconventional p-d Orbital Hybridization over Porous High-entropy Alloy Metallene for Efficient Electrosynthesis of Nylon-6 Precursor.

Renewable electricity driven electrosynthesis of cyclohexanone oxime (C6H11NO) from cyclohexanone (C6H10O) and nitrogen oxide (NOx) is a promising alternative to traditional environment-unfriendly industrial technologies for green synthesis of C6H11NO. Precisely controlling the reaction pathway of the C6H10O/NOx-involved electrochemical reductive coupling reaction is crucial for selectively producing C6H11NO, which is yet still challenging. Herein, we report a porous high-entropy alloy PdCuAgBiIn metallene (HEA-PdCuAgBiInene) to boost the electrosynthesis of C6H11NO from C6H10O and nitrite, achieving a high Faradaic efficiency (47.6%) and almost 100% yield under ambient conditions. In situ Fourier transform infrared spectroscopy and theoretical calculations demonstrate that unconventional orbital hybridization between d-block metals and p-block metals could regulate the local electronic structure of active sites and induce electron localization of electron-rich Pd sites, which tunes the active hydrogen supply and facilitates the generation and enrichment of key intermediates NH2OH* and C6H10O*, and efficiently promotes their C-N coupling to selectively produce C6H11NO.

Porous ß-cyclodextrin polymers for rapid and efficient removal of organic micropollutants from water: The role of sulfonation and porosity on adsorption performance.

Removal of organic micropollutants (OMPs) from water, especially hydrophilic and ionized ones, is challenging for water remediation. Herein, porous ß-cyclodextrin polymers (PCPs) with tailored functionalization were prepared based on molecular expansion strategy and sulfonation. Partially benzylated ß-cyclodextrin was knotted by external crosslinker to form PCP1, and knotting PCP1 by expansion molecule generated PCP2. PCP1 and PCP2 were sulfonated to achieve PCP1-SO3H and PCP2-SO3H. Based on systematical adsorption evaluation toward multiple categories of OMPs, it was found that the introduced strong polar -SO3H group could bring strong hydrogen bonding and electrostatic interactions. PCP2 showed the highest surface (998.97 m2/g) displayed more excellent adsorption performance toward neutral and anionic OMPs, and the adsorption mechanism for this property of PCP2 was dominated by hydrophobic interactions. In addition, the PCP1-SO3H with the lowest surface area (39.75 m2/g) rather than PCP2-SO3H with higher surface (519.28 m2/g) exhibited more superior adsorption towards hydrophilic and cationic OMPs, benefiting by hydrogen bonding and electrostatic interactions as well as appropriate porosity. These results not only confirmed the performance enhancement of PCPs through the integration of novel preparation strategy, but also provided fundamental guidance for PCPs design for water remediation.

Statistical physical modeling insights for urinary analgesic drug adsorption on carbon nanomaterial derivative.

The presence of phenazopyridine in water is an environmental problem that can cause damage to human health and the environment. However, few studies have reported the adsorption of this emerging contaminant from aqueous matrices. Furthermore, existing research explored only conventional modeling to describe the adsorption phenomenon without understanding the behavior at the molecular level. Herein, the statistical physical modeling of phenazopyridine adsorption into graphene oxide is reported. Steric, energetic, and thermodynamic interpretations were used to describe the phenomenon that controls drug adsorption. The equilibrium data were fitted by mono, double, and multi-layer models, considering factors such as the numbers of phenazopyridine molecules by adsorption sites, density of receptor sites, and half saturation concentration. Furthermore, the statistical physical approach also calculated the thermodynamic parameters (free enthalpy, internal energy, Gibbs free energy, and entropy). The maximum adsorption capacity at the equilibrium was reached at 298 K (510.94 mg g-1). The results showed the physical meaning of adsorption, indicating that the adsorption occurs in multiple layers. The temperature affected the density of receptor sites and half saturation concentration. At the same time, the adsorbed species assumes different positions on the adsorbent surface as a function of the increase in the temperature. Meanwhile, the thermodynamic functions revealed increased entropy with the temperature and the equilibrium concentration.

Effective elimination of Hg(II) from water bodies with acid-modified magnetic biomass spent coffee grounds: conditional optimization and application.

To maximize the efficiency of biomass waste utilization and waste management, a novel acid-modified magnetic biomass spent coffee grounds (NiFe2O4/SCG) was obtained by pyrolysis at 473 K and co-precipitation methods and employed to eliminate bivalent mercury (Hg(II)) in water bodies. The prepared NiFe2O4/SCG adsorbent exhibits remarkable magnetism with a strength of 45.78 emu/g and can easily be separated from water via a magnetic force. The adsorption of Hg(II) over the NiFe2O4/SCG has an optimal conditions of pH = 8, T = 39 ℃, and dosage of 0.055 g/L, and the maximal adsorption capacity for Hg(II) is 167.44 mg/g via Response Surface Methodology optimization. The removal of Hg(II) over NiFe2O4/SCG primarily involves ion exchange, electrostatic attraction, and chelation; conforms to the pseudo-second-order kinetic and Langmuir models; and is an endothermic reaction. Additionally, the magnetic biomass NiFe2O4/SCG has good regeneration capability and stability. The application research reveal that inorganic salt ions, nitrogen fertilizer urea, humus, and other contaminants in different actual water bodies (river water, lake water, and the effluent of sewage treatment plant) have little effect on the adsorption of Hg(II) over the NiFe2O4/SCG. The prepared adsorbent NiFe2O4/SCG has practical application value for removing Hg(II) from water bodies.

Rapid eco-friendly selective dye removal using modified chitosan-based sponges: Synthesis, characterization, and application.

The ongoing challenge of water scarcity persists alongside a concerning rise in water pollution driven by population expansion and industrial development. As a result, urgent measures are imperative to address the pressing need for a clean and sustainable water supply. In this study, a sustainable and green approach was utilized to prepare four chitosan-based sponges from a chemically modified chitosan with different alkyl chains in aqueous medium and at room temperature. The resulting sponges displayed excellent stability in water with outstanding dye removal efficiency. The adsorption capacity was associated with the alkyl chain length incorporated to the polymer backbone. All sponges displayed a high adsorption capacity of methyl orange (MO) ranges between 238 and 380 mg g-1, while a low capacity were obtained for methylene blue (MB) and Rhodamine B (RB). Competitive adsorption experiments were conducted on binary and ternary mixtures to assess the selective removal of MO from a mixture of dyes in which the separation factor was found to be ranging between 1.6 and 32. The adsorption kinetics isotherms of all sponges followed the pseudo-second-order, and the Langmuir model was found to be more suitable than the Freundlich for the adsorption of MO on the sponges. The chitosan-based sponges showed stable performance, robustness and reusability over 5 adsorption-desorption cycles, indicating their great potential for water treatment applications.

Chitosan extraction from Amanita phalloides: yield, crystallinity, degree of deacetylation, azo dye removal and antibacterial properties.

Chitosan, a biopolymer obtained from chitin, is known for its remarkable adsorption abilities for dyes, drugs, and fats, and its diverse array of antibacterial characteristics. This study explores the extraction and characterization of chitosan from the mycelium of Amanita phalloides. The moisture content, ash content, water binding capacity, fat binding capacity, and degree of deacetylation of the extracted chitosan were determined. The chitosan exhibited a high yield of 70%, crystallinity of 49.07%, a degree of deacetylation of 86%, and potent antimicrobial properties against both Gram-negative and Gram-positive bacteria. The study also examined the adsorption capabilities of chitosan to remove methylene blue (MB) dye by analysing specific factors like pH, reaction time, and MB concentration using the response surface model. The highest degree of MB dye removal was 91.6% at a pH of 6, a reaction time of around 60 min and an initial dye concentration of 16 ppm. This experimental design can be applied for chitosan adsorption of other organic compounds such as dyes, proteins, drugs, and fats.

Novel Schiff's base-assisted synthesis of metal-ligand nanostructures for multi-functional applications: Detection of catecholamines/antibiotics, removal of tetracycline, and antifungal treatment against plant pathogens.

The development of nanozymes (NZ) for the simultaneous detection of multiple target chemicals is gaining paramount attention in the field of food and health sciences, and waste management industries. Nanozymes (NZ) effectively compensate for the environmental vulnerability of natural enzymes. Considering the development gap of NZ with diverse applications, we synthesized versatile Schiff's base ligands following a facile route and readily available starting reagents (glutaraldehyde, aminopyridines). DPDI, one of the synthesized ligands, readily reacted with transition metal ions (Cu+2, Ag+1, Zn+2 in specific) under ambient conditions, yielding the corresponding nanoparticles/MOF. The structures of ligands and their products were confirmed using various analytical techniques. The enzymatic efficacy of DPDI-Cu (km 0.25 mM=, Vmax = 10.75 µM/sec) surpassed Tremetese versicolor laccase efficacy (km 0. 5 mM=, Vmax = 2.15 µM/sec). Additionally, DPDI-Cu proved resilient to changing pH, temperature, ionic strength, organic solvent, and storage time compared to laccase and provided reusability. DPDI-Cu proved promising for colorimetric detection of dopamine, epinephrine, catechol, tetracycline, and quercetin. The mechanism of oxidative detection of TC was studied through LC/MS analysis. DPDI-Cu-bentonite composite efficiently adsorbed tetracycline with maximum Langmuir adsorption of 208 mg/g. Moreover, DPDI/Cu and DPDI-Ag nanoparticles possessed antifungal activity exhibiting a minimum inhibitory concentration of 400 µg/mL and 3.12 µg/mL against Aspergillus flavus. Florescent dye tracking and SEM/TEM analysis confirmed that DPDI-Ag caused disruption of the plasma membrane and triggered ROS generation and apoptosis-like death in fungal cells. The DPDI-Ag coating treatment of wheat seeds confirmed the non-phytotoxicity of Ag-NPs.

Enhancing irrigation water quality efficiently with potassium feldspar-derived adsorbent: Heavy metal detoxification and nutrient augmentation.

The pollution of Pb2+ and Cd2+ in both irrigation water and soil, coupled with the scarcity of vital mineral nutrition, poses a significant hazard to the security and quality of agricultural products. An economical potassium feldspar-derived adsorbent (PFDA) was synthesized using potassium feldspar as the main raw material through ball milling-thermal activation technology to solve this problem. The synthesis process is cost-effective and the resulting adsorbent demonstrates high efficiency in removing Pb2+ and Cd2+ from water. The removal process is endothermic, spontaneous, and stochastic, and follows the quasi-second-order kinetics, intraparticle diffusion, and Langmuir model. The adsorption and elimination of Pb2+ and Cd2+ is largely dependent on monolayer chemical sorption. The maximum removal capacity of PFDA for Pb2+ and Cd2+ at room temperature is 417 and 56.3 mg·g-1, respectively, which is superior to most mineral-based adsorbents. The desorption of Pb2+/Cd2+ on PFDA is highly challenging at pH≥3, whereas PFDA and Pb2+/Cd2+ are recyclable at pH≤0.5. When Pb2+ and Cd2+ coexisted, Pb2+ was preferentially removed by PFDA. In the case of single adsorption, Pb2+ was mainly adsorbed onto PFDA as Pb2SiO4, PbSiO3·xH2O, Pb3SiO5, PbAl2O4, PbAl2SiO6, PbAl2Si2O8, Pb2SO5, and PbSO4, whereas Cd2+ was primarily adsorbed as CdSiO3, Cd2SiO4, and Cd3Al2Si3O12. After the complex adsorption, the main products were PbSiO3·xH2O, PbAl2Si2O8, Pb2SiO4, Pb4Al2Si2O11, Pb5SiO7, PbSO4, CdSiO3, and Cd3Al2Si3O12. The forms of mineral nutrients in single and complex adsorption were different. The main mechanisms by which PFDA removed Pb2+ and Cd2+ were chemical precipitation, complexation, electrostatic attraction, and ion exchange. In irrigation water, the elimination efficiencies of Pb2+ and Cd2+ by PFDA within 10 min were 96.0 % and 70.3 %, respectively, and the concentrations of K+, Si4+, Ca2+, and Mg2+ increased by 14.0 %, 12.4 %, 55.7 %, and 878 %, respectively, within 60 min. PFDA holds great potential to replace costly methods for treating heavy metal pollution and nutrient deficiency in irrigation water, offering a sustainable, cost-effective solution and paving a new way for the comprehensive utilization of potassium feldspar.

Magnetic Hollow Fibers of Covalent Organic Frameworks (COF) for Pollutant Degradation and Adsorptive Removal.

The shaping of covalent organic frameworks (COFs), requiring the conversion of non-processible COF powders into applicable architectures with additional functionality, remains a challenge. Using pre-electrospun polymer fibers as a sacrificial template, herein, we report a green synthesis of an architecture in the form of COF hollow fibers with an inner layer of peroxidase-like iron oxide nanoparticles as a catalytic material. When compared to peroxidase-like pristine iron oxide nanoparticles, these COF hollow fibers demonstrate higher catalytic breakdown of crystal violet due to their peroxidase-like activity via advanced oxidation process. Furthermore, as a potential adsorbent, hollow COF fibers exhibit significantly effective adsorption capacity and removal efficiency of organic solvent and oil from water. Because of their magnetic nature, COF hollow fibers can be easily recovered and have exhibited high recycling stability for both catalytic dye degradation and organic solvent removal from water.

Green Technology Approach Towards the Removal of Heavy Metals, Dyes, and Phenols from Water Using Agro-based Adsorbents: A Review.

The swift pace of socioeconomic development and climatic change have put significant strain on the quality of water resources. While, the bulk availability of agro-based materials arising from nature and agricultural practices has paved the way for researchers in eradicating toxic industrial pollutants such as dyes, heavy-metals, phenolic-compounds, pesticides, etc. by using them as adsorbents. In the area of pollution remediation, inventive technologies have been developing. The adsorption technique stands out among the other wastewater-treatment methods as it is simple, easy, efficient, and cost-effective. The agro-based adsorbents their use in this area contributes to minimizing natural waste. They can be employed in their original raw-form or after undergoing simple processes such as drying, grinding, and carbonization. Moreover, these adsorbents are typically modified physically or chemically to change their surface properties and improve their adsorption efficiency. The low-cost agro adsorbents have shown efficient adsorption capacities towards removing various organic and hazardous water pollutants. With a few exceptions, majority of adsorbents have demonstrated heavy metals, dyes and phenol removal efficiencies exceeding 90%. This review summarizes the available information and strategies for using agro-based adsorbents to eliminate hazardous water pollutants. It is a prospective area for research in the field of environmental pollution.

Coconut shell-based biochars produced by an innovative thermochemical process for obtaining improved lignocellulose-based adsorbents.

The urgent need for a simple and cost-effective thermochemical process to produce biochar has prompted this study. The aim was to develop a straightforward thermochemical process under O2-limited conditions for the production of coconut-based biochar (CBB) and to assess its ability to remove methylene blue (MB) through adsorption, comparing it with CBB produced by slow pyrolysis. CBBs were obtained under different atmospheric conditions (O2-limited, muffle furnace biochar (MFB); and inert, pyrolytic reactor biochar (PRB)), at 350, 500, and 700 °C, and for 30 and 90'. MFB and PRB were characterized using FTIR, RAMAN, SEM, EDS, and XRD analyses. Adsorption tests were conducted using 1.0 g L-1 of MFB and PRB, 10 mg L-1 of MB at 25 °C for 48 h. Characterization revealed that atmospheric conditions significantly influenced the yield and structural features of the materials. PRB exhibited higher yields and larger cavities than MFB, but quite similar spectral features. Adsorption tests indicated that MFB and PRB had qt values of 33.1 and 9.2 mg g-1, respectively, which were obtained at 700 °C and 90', and 700 °C and 30', respectively. This alternative method produced an innovative and promising lignocellulose-based material with great potential to be used as a biosorbent.

Environmental remediation potential of a pioneer plant (Miscanthus sp.) from abandoned mine into biochar: Heavy metal stabilization and environmental application.

Pyrolysis stands out as an effective method for the disposal of phytoremediation residues in abandoned mines, yielding a valuable by-product, biochar. However, the environmental application of biochar derived from such residues is limited by the potential environmental risks of heavy metals. Herein, Miscanthus sp. residues from abandoned mines were pyrolyzed into biochars at varied pyrolysis temperatures (300-700 °C) to facilitate the safe reuse of phytoremediation residues. The results showed that pyrolysis significantly stabilizes heavy metals in biomass, with Cd exhibiting the most notable stabilization effect. Acid-soluble/exchangeable and reducible fractions of Cd decreased significantly from 69.91 % to 2.52 %, and oxidizable and residue fractions increased approximately 3.24 times at 700 °C. The environmental risk assessment indicated that biochar pyrolyzed over 500 °C pose lower environmental risk (RI < 30), making them optimal for the safe utilization of phytoremediation residues. Additionally, adsorption experiments suggested that biochars prepared at higher temperature (500-700 °C) exhibit superior adsorption capacity, attributed to alkalinity and precipitation effect. This study highlights that biochars produced by pyrolyzing Miscanthus sp. from abandoned mines above 500 °C hold promise for environmental remediation, offering novel insight into the reutilization of metal-rich biomass.

Utilizing silica fume and synthetically produced mesoporous silicas for simulated flue gas CO2 adsorption.

Carbon capture and storage (CCS) is crucial in mitigating greenhouse gas emissions. Solid adsorbents, notable for their reusability and corrosion resistance, are gaining attention in CO2 gas separation. This study uses Silica fume as an adsorbent and silica source for SiO2 and MCM-41 silica-based adsorbents. Silica was extracted via an alkaline dissolution method, and adsorbents were synthesized using a CO2-induced precipitation method, chosen for its shorter synthesis time and CO2 utilization. The effects of pore volume, average pore diameter, and specific surface area on amine loading and CO2 adsorption capacity were investigated using CTAB surfactant in SiO2 synthesis, resulting in MCM-41. The synthesized adsorbents were modified with TEPA and DEA amines due to their high affinity for CO2. After determining optimal amine loading, the impact of combining TEPA with DEA was examined. The highest CO2 adsorption capacity under simulated flue gas conditions (15% volume CO2 and 85% volume N2) was 198 milligrams per gram of adsorbent for the SiO2 adsorbent functionalized with 50% by weight amine (28% TEPA and 22% DEA). Variations in CO2 adsorption over time, the influence of adsorbent quantity on adsorption capacity, the affinity of the adsorbent for N2 adsorption, and the adsorption-desorption cycle were investigated. The 28%TEPA-22%DEA-SiO2 adsorbent emerged as the optimal choice due to its large total volume and average pore diameter, absence of a template in its structure, excellent performance in CO2 adsorption, lack of affinity for N2, and robust adsorption-desorption stability.