Commercial Adsorbents Research Articles

Adsorbability of a Wide Range of Per- and Polyfluoroalkyl Substances on Granular Activated Carbon, Ion Exchange Resin, and Surface Modified Clay

The increased detection of understudied per- and polyfluoroalkyl substances (PFAS) in environmental matrices has highlighted the need to evaluate the treatability of a wide-range of PFAS by sorption-based processes. This study investigated the efficacy of three commercial adsorbents (i.e., granular activated carbon (GAC), surface modified clay (SMC), and anionic exchange resin (AER)) for the removal of a wide range of cationic, zwitterionic, and anionic PFAS from an aqueous film forming foam (AFFF)-impacted groundwater employing rapid small-scale column tests (RSSCTs) coupled with high resolution mass spectrometry (HRMS) and suspect screening analysis (SQ). AER exhibited later breakthrough times for the majority of anionic and zwitterionic PFAS compared to SMC and GAC. However, both AER and SMC exhibited negligible removal of cationic PFAS presumably due to the reliance of these adsorbents on electrostatic interactions and the counteraction of hydrophobic forces caused by the repulsion between cationic PFAS and positively charged surfaces of AER and SMC. GAC, being a non-selective adsorbent, was largely unaffected by the ionic charge of the evaluated PFAS with molecular structure having a bigger impact on adsorbability. The detection of a variety of PFAS classes in the investigated AFFF-impacted groundwater enabled assessment of the relative impact of chemical structure on adsorptive removal of PFAS. Chain-length dependent adsorption was observed across all investigated anionic and zwitterionic PFAS classes. The PFAS structures possessing hydroxyl and/or methyl functional groups exhibited later breakthrough times compared to their homologues lacking these functional groups and cyclic/unsaturated structures were removed less efficiently compared to their linear/saturated homologues. In the case of perfluoroalkyl acid (PFAA)-derivative structures, hydrogen-substituted classes (i.e., H-PFAAs) were removed more efficiency than PFAAs while keto-substituted structures (i.e., K-PFSA) and pentahydrido-fluoroalkane sulfates (PeH-FAOS) exhibited lower adsorbability compared to PFAAs for all adsorbents. Oxa-PFAAs (O-PFSA; isomer class of PFA-OS) on the other hand demonstrated higher adsorbability compared to PFAAs in the case of AER-like adsorbents, while this trend was reversed for GAC.

LITERATUR STUDI MENGENAI ADSORBEN LIMBAH CANGKANG HEWAN LAUT DALAM BERBAGAI KEILMUAN

The utilization of marine animal waste as a base material for adsorbents has become an increasingly popular research topic across various scientific fields, including chemistry, environmental science, and materials science. Waste from marine animals, such as crab shells, oyster shell, seashell, and shrimp shell, possesses high potential to be processed into adsorbents due to their abundant calcium carbonate, chitosan, and protein content. The use of this waste as adsorbents not only provides a solution to environmental issues related to the accumulation of organic waste but also offers cheaper and eco-friendly alternative for water treatment, air purification, and contaminated soil remediation. Research has shown that marine animal waste-based adsorbents are effective in removing various pollutants, including heavy metals, textile dyes, and hazardous organic compounds. With specific modification techniques, the performance of these adsorbents can be enhanced, making them competitive with commercial adsorbents. Overall, the use of marine animal waste as adsorbents represents an innovative approach that contributes to waste reduction and the enhancement of environmental sustainability.

Highly efficient adsorption and removal of phthalate esters by polymers of intrinsic microporosity

In recent years, phthalate esters (PAEs) have been found to be endocrine disruptors that pose a serious safety threat to human health. Currently, adsorption is one of the most efficient technologies to remove PAEs, and the development of adsorbent materials that combine high adsorption capacity and short equilibrium time is a challenging problem. In this study, PIM-1, a typical representative of polymers of intrinsic microporosity (PIMs), was prepared through three methods and first used as adsorbents for PAEs removal. PIM-1 prepared under high temperature (HT-PIM-1) exhibited a high capacity of 787mg/g for dibutyl phthalate (DBP), a prevalent PAE in water, which is significantly higher than most reported adsorbents. Furthermore, more than 90.0% of the equilibrium adsorption capacity can be reached within 30mins. In addition, the adsorption of DBP could be inhibited by ethanol due to the enhanced interaction between DBP and ethanol, which could be revealed by molecular simulation. The adsorption mechanism of PAEs on PIM-1 mainly included hydrophobic interactions, π-π interactions, together with the size matching between PAEs and hierarchical pores of PIM-1. This study provides an idea for the application of PIMs for PAEs removal with high adsorption capacity and high efficiency. Environmental ImplicationPhthalate esters (PAEs) are emerging pollutants that pose a significant threat to public health and safety. They have been detected not only in environmental water but also in alcoholic beverages. Adsorption is widely preferred for removing PAEs, and the adsorption of PAEs in alcoholic solutions is a more challenging process compared to pure water. In this study, PIM-1 with o-phenyl groups similar to PAEs were first used as adsorbents for PAEs and demonstrated a remarkable adsorption capacity in both water (787mg/g) and alcoholic solutions (398mg/g) within a short period, surpassing the performance of commercial adsorbents.

Enhanced detection of catecholamines in human urine using Cis-diol-microporous organic networks with PT-SPE and HPLC-MS/MS

A novel cis-diol-microporous organic networks (MONs-2OH) material was synthesized via room temperature and Sonogashira coupling reactions, which exhibits exceptional adsorption properties for catecholamines (CAs). MONs-2OH demonstrates robust hydrogen bonding and π-π stacking interactions, crucial for effective adsorption. The MONs-2OH was incorporated into pipette tip solid-phase extraction and developed a new method for detecting CAs in human urine using HPLC-MS/MS. Characterization of the adsorbent revealed its high stability, large specific surface area, abundant phenolic hydroxyl groups, rapid extraction speed, and superior adsorption efficiency. The method achieved a wide linear range (0.5–500 ng/mL), low detection limits (0.06–0.26 ng/mL), high accuracy (90.4 %-99.4 %), and excellent precision (RSD ≤ 10 %). Comparative studies showed MONs-2OH outperforms commercial adsorbents in terms of recovery and adsorption capacity. The results underscore the potential of MONs-2OH for rapid and sensitive CAs determination, offering significant advantages for the auxiliary diagnosis of depression and enhancing the application of PT-SPE in sample pretreatment.

Ultra-strong adsorption of ammonia nitrogen from low-temperature and complex systems by Prussian blue analogue

The aquatic ecosystem is threatened globally by eutrophication due to ammonia nitrogen inputs from wastewater. Developing high-performance adsorbents with high removal efficiency and selectivity for ammonia nitrogen is pivotal to ecological equilibrium. Here, the removal of ammonia nitrogen by a combined process of Co-based Prussian blue (NaCo-PBA) and coagulants was studied for the first time. The maximum adsorptive capacity of ammonia nitrogen by NaCo-PBA was 52.72 mg/g, and the removal reached 99 %. Compared with traditional adsorbents, NaCo-PBA showed high adsorption amounts (9–42 times). Most importantly, NaCo-PBA exhibited selectivity in complex systems and its adsorption quantity reached 42.6 mg/g in real domestic wastewater, compared to 4.7 mg/g for commercial adsorbent. NaCo-PBA was used in the coagulation and co-adsorption process to facilitate the separation of multiple contaminants in water. It is reasonable to believe that the collaboration between NaCo-PBA with special structure and coagulation will bring a new perspective to nitrogen removal in complex systems.

Exploring the superior adsorption capacity of multi-layer graphene/alginate granules for the removal of methylene blue dye from water

Graphene-based materials are gaining increasing attention towards their use in manufacturing and environmental applications. In this context, multi-layer graphene (MG) has been recently applied for the adsorption of contaminants from water resulting in promising results. However, the extreme lightness of this material often makes it difficult to handle due to its potential dispersion in the surrounding environment as well as to its transport and loss with the effluent. In this study, a novel granular material was synthesized by embedding MG into an alginate matrix, resulting in the so-called granular MG (GMG). This material was tested for the adsorption of methylene blue (MB) from water, which is a typical dye used in textile industries and must be removed from the effluent. GMG materials with different MG contents (5 and 20 %) were compared with MG and a commercial adsorbent to assess their adsorption capacity and the most performing material was selected for in-depth physical and chemical characterization. The structural, surface, kinetic, isotherm, and thermodynamic properties, the pH and temperature dependence, as well as the regeneration and reuse of GMG 5% were investigated through batch adsorption tests under different operating conditions. The study reveals that GMG 5% has a superior adsorption capacity compared to the tested materials and can be considered as a promising alternative to commercial carbon-based materials according to techno-economic considerations.

Cyano-functionalized porous hyper-crosslinked cationic polymers for efficient preconcentration and detection of phenolic endocrine disruptors in fresh water and fish

Sensitively analyzing phenolic endocrine-disrupting chemicals (EDCs) in environmental substrates and aquatic organisms provides a significant challenge. Here, we developed a novel porous hyper-crosslinked ionic polymer bearing cyano groups (CN-HIP) as adsorbent for the highly efficient solid phase extraction (SPE) of phenolic EDCs in water and fish. The CN-HIP gave an excellent adsorption capability for targeted EDCs over a wide pH range, and the adsorption capacity was superior to that of several common commercial SPE adsorbents. The coexistence of electrostatic forces, hydrogen bond, and π-π interactions was confirmed as the main adsorption mechanism. A sensitive quantitative method was established by coupling CN-HIP based SPE method with high-performance liquid chromatography for the simultaneously determining trace bisphenol A, bisphenol F, bisphenol B and 4-tert-butylphenol in fresh water and fish. The method afforded lower detection limits (S/N = 3) (at 0.03–0.10 ng mL−1 for water and 0.8–4.0 ng g−1 for fish), high accuracy (the recovery of spiked sample at 88.0%–112 %) and high precision (the relative standard deviation < 8.5 %). This work provides a feasible method for detecting phenolic EDCs, and also opens a new perspective in developing functionalized cationic adsorbent.

Synthesis of mesoporous γ-alumina from a low-grade boehmite ore: Effect of thermal/chemical processing order on physico-chemical characteristics of adsorbent and regeneration of used transformer oils

Mesoporous γ-alumina adsorbents were synthesized from a low-grade boehmite ore, using the heat-treatment/acid-leaching (TC) and vice-versa (CT), under 400–600℃, 2–6 M HCl and H2SO4 solutions. The crystallinity of active species, morphology, elemental mapping, specific surface area, gravimetric phase changes, and chemical composition of the samples were characterized. The 0.50–1.00 mm γ-alumina prepared through heating, and followed by acid leaching with HCl (TC sample) presented mesoporous structure with the highest specific surface area of 245.802m2/g, pore volume 0.32773cm3/g, and average pore diameter of 44.3420A0. Using both CT and TC adsorbents, along with a commercial adsorbent, for the regeneration of used transformer oil, the TC adsorbent demonstrated the best performance, resulting in improved oil properties such as viscosity, interfacial tension, total acid number, dielectric dissipation factor, resistivity, and moisture content. Furthermore, the TC adsorbent was affected less by surface attrition and producing fine debris during recovery of oil compared to the commercial one.

Removal of two cationic dyes by adsorption on F400 commercial activated carbon

In this investigation, we studied the removal of two cationic dyes, methyl green MG and malachite green Mc G, by a commercial adsorbent. This adsorbent is a F400 activated carbon with a specific surface area of 1203 m2. g-1, which is expected to be high compared with ordinary adsorbents. Adsorption tests were carried out on both dyes in batch mode. The results show that both kinetics are fast, with equilibrium reached after 20 minutes and 30 minutes respectively for Methyl Green and Malachite Green. The kinetics of both dyes are well adapted to pseudo-second order, and for the intraparticle diffusion model, two lines can be distinguished for each dye, proving the existence of two adsorption steps. The isotherm for this system reveals an L-type shape for both dyes, in line with the classification of Giles &amp; al. so there is little competition for sorption sites between solvent and adsorbate. The adsorption isotherms for methyl green by PAC obeyed the Langmuir, Freundlich and Temkin models, while that for malachite green followed only the Langmuir isotherm, with a much higher maximum amount.

Dynamics of water adsorption on SAPO-34: Comparison of three adsorbent bed configurations of adsorption chillers

Intensification of the adsorption dynamics is a strategic way to make adsorption chillers and heat pumps more competitive with conventional vapour compression systems. This can be achieved by consolidating the adsorbent bed with a heat exchanger to enhance heat transfer. This work investigates the dynamics of water adsorption on a commercial adsorbent SAPO-34 for three bed configurations, namely, a reference bed consisting of a monolayer of loose beads located on an aluminium plate, and two consolidated beds – a monolayer of beads glued to the plate, and a homogeneous coating of the plate prepared with binder. The morphology and texture of the prepared beds were studied by optical and scanning electron microscope techniques as well as by low temperature nitrogen adsorption. Six binders involved, both organic (hydroxyethyl cellulose, polyvinylpyrrolidone, polyaniline) and inorganic (heat-conductive compound CPTD, bentonite clay, colloidal silica sol), produced varying effects. It was found that the most preferred configuration involves SAPO beads glued to the plate with bentonite for which the heat transfer was enhanced by a factor of 1.2–1.7 while maintaining sufficient mass transfer. The effective heat transfer coefficient was measured for the most promising binders and selected configurations, and varied between 120 and 248 W/(m2 K). The heat transfer acceleration permitted the specific cooling power (at a conversion of 0.8) to increase from 2.7 kW/kg for loose beads of 0.8–0.9 mm size to 3.5 kW/kg for the same beads bound with bentonite. Thus, gluing pre-made commercial adsorbent beads with heat-exchanger with suitable binders presents a simple and promising method to enhance the adsorption dynamics, resulting in a more compact design of adsorption chillers.

Exploring the Effects of an Alfalfa Leaf-Derived Adsorbent on Microbial Community, Ileal Morphology, Barrier Function, and Immunity in Turkey Poults during Chronic Aflatoxin B1 Exposure.

This article follows-up on our recently published work, which evaluated the impact of the addition of an alfalfa leaf-derived adsorbent in the aflatoxin B1 (AFB1)-contaminated diet in regard to the production parameters, blood cell count, serum biochemistry, liver enzymes, and liver histology of turkey poults. This paper presents complementary results on microbial community, ileal morphology, barrier function, and immunity. For this purpose, 350 1-day-old female turkey poults were randomly distributed into five groups: (1) Control, AFB1-free diet; (2) AF, AFB1-contaminated diet at 250 ng/g; (3) alfalfa, AFB1-free diet + 0.5% (w/w) adsorbent; (4) alfalfa + AF, AFB1-contaminated diet at 250 ng/g + 0.5% (w/w) adsorbent; and (5) YCW + AF, AFB1-contaminated diet at 250 ng/g + 0.5% (w/w) commercial yeast cell wall-based adsorbent (reference group). In general, in the AF group, the growth of opportunistic pathogens was promoted, which lead to gut dysbacteriosis, mainly influenced by Streptococcus lutetiensis. Conversely, a significant increase in beneficial bacteria (Faecalibacterium and Coprococcus catus) was promoted by the addition of the plant-based adsorbent. Moreover, the AF group had the lowest villus height and a compromised barrier function, as evidenced by a significant (p < 0.05) increase in fluorescein isothiocyanate dextran (FITC-d), but these negative effects were almost reversed by the addition of the alfalfa adsorbent. Furthermore, the AF + YCW and alfalfa + AF groups exhibited a significant increase in the cutaneous basophil hypersensitivity response compared to the rest of the experimental groups. Taken together, these results pointed out that the alfalfa counteracts the adverse effects of AFB1 in poults, facilitating the colonization of beneficial bacteria and improving the barrier function of the turkey poults.

Characterization and application of LDH with chitosan composites investigated by positron annihilation lifetime spectroscopy and surface texture for the adsorption of methyl orange

With a rapid increase in industrial growth around the world, the demand for an entirely novel category of nanoparticles and technologies for wastewater treatment has become a key concern for environmental protection. Recently, hybrids of layered double hydroxides (LDH), particularly those containing LDH, have gained attention as potential nanoscale adsorbents for water treatment. Recent research has shown that LDH-containing composites are interesting versatile materials with the ability to be used in energy storage, photocatalysis, nanocomposites, and water treatment. In the current work, LDH-containing composites were utilized as adsorbents for the purpose of purifying water. The adsorbents investigated are Zn–Co–Fe/LDH/Chitosan-in situ sample preparation (LDH/CS1) and Zn–Co–Fe/LDH/Chitosan-ex situ sample preparation (LDH/CS2). Furthermore, LDH/CS1 and LDH/CS2 were investigated for wastewater treatment from methyl orange dye (MO) with various adsorption conditions. When the initial MO concentration was 20 mg/L and the amount of adsorbent was 0.1 g, the removal efficiency reached 72.8 and 91.7% for LDH/CS1 and LDH/CS2, respectively. The MO’s maximum adsorption capabilities are 160.78 and 165.89 mg/g for LDH/CS1 and LDH/CS2, respectively, which is much greater than that of comparable commercial adsorbents. MO adsorption onto LDH/CS1 and LDH/CS2 was best characterized by the pseudo-second-order kinetic model. The equilibrium adsorption data was followed by the Freundlich and Langmuir models. The adsorption is favorable as evidenced by the equilibrium parameter RL values for MO adsorption onto LDH/CS1 and LDH/CS2, which were 0.227 and 0.144, respectively. Using the free volume distribution method and the positron annihilation lifetime technique, the nanostructure of the materials was examined.

In English

Fullerenes are interesting objects of research in view of their promising use as a nano-sized additive to coatings, films, adsorbents, as well as active components in medicine, pharmacy, cosmetology. This paper considers the possibility of modifying commercial adsorbents - silica gel and cation-exchanger based on activated carbon with available and inexpensive linear carbon radicals. Behentrimonium chloride (C22H45(CH3)3N+Cl-) and cetyl alcohol (C16H33OН) were chosen as the latter. The obtained adsorbents were compared with a commercial sample of silica gel modified with a linear hydrocarbon radical –C18Н37. The adsorbents were described by the methods of IR spectroscopy, thermogravimetry, the main characteristics of the porous structure were determined by the method of low-temperature adsorption-desorption of nitrogen. Modification of adsorbents based on silica gel leads to a decrease in the specific surface area to 202.4 and 236.5 m2/g and the total pore volume to 0.32 and 0.39 cm3/g, which is almost 2 half source material. Increasing the fraction of micropores contributes to better separation rates of large molecules. Treatment of cation-exchanger based on activated carbon by cation modifier leads to a significant decrease in the specific surface area, as well as to an increase in the size of pores with the predominant formation of mesopores. It is shown that the modification of silica gel is carried out both through silanol and siloxane groups, in contrast to the commercial sample of silica gel. The approximate number of modifier groups on the surface of the original SiO2 matrix was estimated, which is one modifier group ~ per 11 SiO2 molecules. To study the behavior of adsorption of C60, C70 fullerenes and their mixtures on adsorbents, column experiments were carried out with changes in the geometrical parameters of the column and the initial concentrations of the solutions. The results showed that the modified silica gels are potential adsorbents for the separation of a mixture of fullerenes with a ratio of 65/25. Silica gel modified with cetyl alcohol C16H33OH showed the best separation efficiency. By the help of an adsorbent, it is possible to separate C60 - 90.52 % from a less concentrated solution and 87.26 % from a more concentrated solution. To increase the purity of the product, it is necessary to pass the solution through the sorbent 2–3 times. The competitive capability of the proposed modified silica gels, together with economic efficiency, ease of modification, and the possibility of fullerene separation characterize the proposed adsorbents as potential materials for practical application. Due to the significantly lower cost and simpler manufacturing methods, the proposed adsorbents can be used for separation at a large scale.

Bionanocomposite MIL-100(Fe)/Cellulose as a high-performance adsorbent for the adsorption of methylene blue

World production of dyes is estimated at more than 800,000 t·yr−1. The purpose of this research falls within the scope of the choice of an effective, local, and inexpensive adsorbent to remove dyes from wastewater. Adsorptive elimination of dyes by commonly accessible adsorbents is inefficient. The metal–organic frameworks (MOFs) are an important class of porous materials offering exceptional properties as adsorbents by improving separation efficiency compared to existing commercial adsorbents. However, its powder form limits its applications. One way to overcome this problem is to trap them in a flexible matrix to form a hierarchical porous composite. Therefore, in this work, we prepared MIL-100 (Fe) embedded in a cellulose matrix named MIL-100(Fe)/Cell, and used it as an adsorbent of methylene blue (MB) dye. According to the BET analysis, the specific surface area of the synthesized MOF is 294 m2/g which is related to the presence of the cellulose as efficient and green support. The structure of this composite is approximately hexagonal. Adsorption was studied as a function of contact time, adsorbent mass and pollutant load (concentration), and pH, and the effect of each of them on absorption efficiency was optimized. The MIL-100(Fe)/Cell was capable of removing 98.94% of MB dye with an initial concentration of 150 mg/L within 10 min at pH = 6.5 and room temperature. The obtained maximum adsorption capacity was 384.615 mg/g. The adsorption isotherm is consistent with the Langmuir models. The mechanism of MB adsorption proceeds through п-п and electrostatic interactions.

Strychnos potatorum seeds derived magnetic graphene oxide nanocomposite for removal of nickel from wastewater: Adsorption performance, isotherm, kinetic and desorption behavior

In the present study investigates the adsorption of nickel ions by Strychnos potatorum seeds derived magnetic graphene oxide (SP-MGO). The fitness of the derived material was analyzed using BET and zeta seizer which proves the suitability of this adsorbent for adsorption process. The surface area, pore size and pore volume were obtained through BET analysis and the results were 51.798 (m2/g), 16.795 nm and 0.217 (cm3/g) respectively. And the size of the nanoparticle was measured using zeta seizer. For achieving maximum adsorption capacity, the following optimized conditions were; 60 min of contact time, under pH of 8, with 10 mg of SP-MGO dose, for the concentration of 10 mg/l, at the temperature of 35 °C. Freundlich isotherm (R2 =0.999) and pseudo second order (R2 =0.997) was well described the adsorption process. According to the isotherm model the adsorption of nickel ions occurs by multilayer of adsorption on heterogeneous surface of SP-MGO nanoadsorbent and also by chemisorption according to kinetic model. The Langmuir monolayer adsorption capacity (Q max) obtained by SP-MGO was 6.66 mg/g. The regeneration ability of SP-MGO was only reduced 17.1 % even after five cycles of adsorption runs. Overall, the SP-MGO can be a potential option for develop into a commercial adsorbent for industrial use to eliminate the pollutants from waste water.

Characterizing Macroporous Ion Exchange Membrane Adsorbers for Natural Organic Matter (NOM) Removal-Adsorption and Regeneration Behavior.

Addressing the characterization of Natural Organic Matter (NOM) removal by functionalized membranes in water treatment, this study evaluates the effectiveness of two commercial ion-exchange membrane adsorbers: Sartobind® Q (with quaternary amines) and D (with tertiary amines). Using Suwannee River NOM (SRNOM) as a surrogate, Langmuir adsorption isotherms revealed maximum capacities (Qmax) of 2966 ± 153 mg C/m2 and 2888 ± 112 mg C/m2, respectively. Variations in flux from 50 to 500 LMH had a minimal impact on breakthrough times, proving low diffusion limitations. The macroporous (3-5 µm) functionalized cellulose-based membranes exhibited high permeabilities of 10,800 L/(h m2 bar). Q maintained positive zeta potential vs. pH, while D's zeta potential decreased above pH 7 due to amine deprotonation and turning negative above an isoelectric point of 9.1. Regeneration with 0.01 M NaOH achieved over 95% DOC regeneration for Sartobind® D, characterizing reversibility through a pH-swing. Cyclic adsorption showed that Q maintained its capacity with over 99% DOC regeneration, while D required acidic conditioning after the first regeneration cycle to mitigate capacity reduction and re-deprotonate the adsorber. These results have demonstrated the potential suitability of adsorber membranes, designed originally for biotechnological purposes, for the possible removal of disinfection byproduct precursors in drinking water treatment.

Investigating the zeolite performance in soil and water conservation after prescribed fires in degraded rangelands

Since the last decades, soil erosion and wildfires are significant threats to most societies and results in the loss of fertile layers and, consequently, in productivity. Changes in soil moisture and stability of soil grains, both in the short- and long-terms after a wildfire occurs, should be also considered as a parameter because they play a key role in plant growth and nutrition too. Adding conditioners to soil also helps to reduce runoff and nutrient losses, which is necessary for the sustainable use of water and ecosystem services. Therefore, the current research was conducted to assess the impacts of zeolite (microporous, crystalline aluminosilicate material commonly applied as commercial adsorbent and catalysts) conservation treatment with diverse amounts (0, 250, 500 and 750 g m−2; Z0 Z1, Z2 and Z3, respectively) on changes of runoff and sediment yield in burned soils with different amounts (250, 500, 750 and 1000 g m−2; F1, F2, F3 and F4, respectively) under laboratory conditions. The experiments were conducted using rainfall simulations with an intensity of 50 mm h−1. The results showed that the highest changes percent of time to runoff (s), runoff volume (l), and soil loss (g) variables after zeolite application at different rates of fire was observed in F4Z3 treatment with 114.94, 76.61 and 82.60%, respectively. We conclude that these results can be useful for a better understanding of the relationships between the fire effects on runoff and sediment considering innovative application of control measures nin-tested to date.

Carbonized polymer dots-based molecular imprinting: An adsorbent with enhanced selectivity for highly efficient recognition and removal of ceftiofur sodium from complex samples

Highly selective removal of residual cephalosporin antibiotics from complex systems is crucial for human health and ecological environment protection. Herein, a newly molecularly imprinted polymer adsorbent (CPDs-NH2@MIP) with enhanced selectivity for ceftiofur sodium (CTFS) was developed by using the special carbonized polymer dots (CPDs-NH2) as functional monomer. The CPDs-NH2 has a nano-spherical structure and functionalized groups (CC, −NH2) via the incomplete carbonization polymerization of citric acid, acrylamide and ethylenediamine, which can accurately interact with CTFS by overcoming steric hindrance, resulting in more precisely imprinted sites and reducing non-imprinted regions in MIP. The presented CPDs-NH2@MIP exhibited excellent adsorption capacity for CTFS (68.62 mg g−1), achieving equilibrium within 10 min, and highly selectivity in mixed solution containing five coexisting substances, with an imprinted factor (5.61). Compared with commercial adsorbents and MIPs prepared with traditional chain functional monomers, the CPDs-NH2@MIP showed significant advantage in selective recognition and separation of target. Analysis of microstructure and mechanism proved that usage of the spherical functional monomer generated precise imprinting sites and dense structure in CPDs-NH2@MIP, which effectively enhanced the selectivity in complex system combined with hydrogen bonding interaction. The idea of designing and using spherical functional monomer will promote the practicality of molecularly imprinted polymer adsorbents.

Isotherm-kinetic equilibrium investigations on absorption remediation potential for COD and ammoniacal nitrogen from leachate by the utilization of paper waste sludge as an eco-friendly composite filler

The paper industry is a major environmental polluter due to paper waste sludge (PWS), often disposed of in hazardous ways. The techniques are employed to disposing of PWS are posing significant environmental hazards and risks to well-being. This study aims to evaluate PWS as a potential replacement for commercial adsorbents like AC and ZEO in treating stabilized leachate. Contact angle analysis of PWS was 92.60°, reveals that PWS to be hydrophobic. Batch adsorption experiments were conducted with parameters set at 200 rpm stirring speed, 120 min contact time, and pH 7. Optimal conditions for COD and NH3–N removal were identified at 120 min contact time, 200 rpm stirring speed, pH 7, and 2.0 g PWS ratio. Removal percentages for COD and NH3–N were 62% and 52%, respectively. Based on the results of the isotherm and kinetic studies, it was observed that the Langmuir and Pseudo second order (PSO) model exhibited greater suitability compared to the Freundlich and Pseudo first order (PFO) model, as indicated by higher values of R-squared (R2). The R-squared of Langmuir for COD and NH3–N were 0.9949 and 0.9919 and for Freundlich model were 0.9855 and 0.9828 respectively. Whereas the R-squared of PFO for COD and NH3–N were 0.9875 and 0.8883 and for PSO were 0.9987 and 0.9909 respectively.

A Study on the Ability of Nanomaterials to Adsorb NO and SO2 from Combustion Gases and the Effectiveness of Their Separation.

Climate neutrality for the year 2050 is the goal assumed at the level of the EU27+UK. As Romania is no exception, it has assumed the gradual mitigation of pollution generated by the energy sector, and by 2030, according to 'Fit for 55', the share of energy from renewable sources must reach 42.5% from total energy consumption. For the rest of the energy produced from traditional sources, natural gas and/or coal, modern technologies will be used to retain the gaseous noxes. Even if they are not greenhouse gases, NO and SO2, generated from fossil fuel combustion, cause negative effects on the environment and biodiversity. The adsorption capacity of different materials, three nanomaterials developed in-house and three commercial adsorbents, both for NO and SO2, was tackled through gas chromatography, elemental analysis, and Fourier-transform infrared spectroscopy. Fe-BTC has proven to be an excellent material for separation efficiency and adsorption capacity under studied conditions, and is shown to be versatile both in the case of NO (80.00 cm3/g) and SO2 (63.07 cm3/g). All the developed nanomaterials generated superior results in comparison to the commercial adsorbents. The increase in pressure enhanced the performance of the absorption process, while temperature showed an opposite influence, by blocking the active centers on the surface.