Search Results (213)

Understanding indoor and outdoor airborne organic mixtures, including semi-volatile organic compounds (sVOCs), remains challenging as quantitative monitoring is often costly and difficult to scale across buildings and individuals. Here we present a low-cost, miniaturised passive sampler-based methodology for static and wearable deployment to generate time-integrated chemical fingerprints and source prioritisation. New sampler devices containing replicate 9 mm sorbent discs (Tenax^® TA and/or polydimethylsiloxane) were deployed for 28 days in indoor (kitchen, bedroom) and outdoor (roadside) environments and worn by five participants; extracts were analysed by liquid extraction and gas chromatography–mass spectrometry (GC-MS) using conservative, transparent criteria for tentative compound identification. Across the household deployments, 52 compounds met inclusion criteria and distinct room-specific and outdoor chemical signatures were observed. Wearable deployments also produced differentiable chemical profiles, with greater similarity among co-inhabitants, but still could differentiate co-habitant activities based on exposure. These results demonstrate the feasibility of using miniature passive samplers to obtain reproducible, information-rich profiles that can help discriminate environments and exposure scenarios. Full article

Cellulose-based materials have been widely investigated as sustainable sorbents for oil spill remediation due to their renewability, biodegradability, low density, and structural diversity. However, reported performance varies substantially across material classes, modification strategies, and testing conditions, making direct comparison difficult. This review summarizes recent progress in cellulose-based sorbents for oil removal, with emphasis on the relationships between processing methods, pore architecture, surface wettability, and sorption behavior. Native cellulose materials, chemically modified cellulose, aerogels, nanocellulose-based systems, and carbonized cellulose are comparatively discussed in terms of oil uptake, selectivity, sorption kinetics, retention stability, reusability, and mechanical performance. The analysis indicates that sorption efficiency is controlled by the combined effects of hierarchical porosity, surface characteristics, and structural integrity. Native materials provide low cost and rapid uptake but limited selectivity, whereas chemically modified systems show improved hydrophobicity and oil retention. Aerogels generally exhibit some of the highest reported absorption capacities but often suffer from low mechanical durability. Nanocellulose-based materials generally offer a balanced combination of sorption capacity and stability, while carbonized materials typically provide enhanced retention at the expense of transport rate. Current limitations, including scalability, durability, and realistic operating conditions, are also discussed to outline future directions for the design of efficient cellulose-based oil sorbents. Full article

Contamination of water bodies by emulsified gasoline hydrocarbons, particularly BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), represents a critical environmental challenge due to their toxicity and resistance to conventional treatment methods. In this study, carbonized biosorbents derived from rice husk (CRH) and walnut shell (CWS) were developed for efficient removal of emulsified gasoline from water. The materials were prepared via carbonization under CO₂ atmosphere (300–800 °C), enabling simultaneous carbonization and activation. Structural and surface properties were characterized using Brunauer–Emmett–Teller (BET) analysis, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray fluorescence spectroscopy (XRF). The results demonstrated a strong dependence of adsorption performance on carbonization temperature, with maximum removal efficiencies of 90.2% (CRH-600) and 96.5% (CWS-700). The superior performance of CWS-700 was associated with its highly developed hierarchical pore structure (up to 670 m² g⁻¹), increased carbon content, and enhanced hydrophobicity. Kinetic studies revealed pseudo-second-order behavior, with equilibrium achieved within 25–30 min at near-neutral pH. Gas chromatographic analysis confirmed the complete removal of BTEX and light hydrocarbons (C1–C9) using CWS-700, highlighting its high selectivity toward aromatic compounds. The adsorption mechanism was attributed to the synergistic effect of micropore filling, hydrophobic interactions, and π-π interactions with aromatic hydrocarbons. The obtained results demonstrate that biomass-derived carbon materials, particularly walnut shell-based sorbents, are promising low-cost candidates for the treatment of complex water systems contaminated with emulsified petroleum hydrocarbons. Full article

The rapid increase in atmospheric ${\mathrm{CO}}_2$ concentration has made carbon capture an essential strategy for mitigating climate change. This review systematically summarizes ${\mathrm{CO}}_2$ capture technologies following the complete process chain. First, three major routes based on combustion stages are introduced: pre-combustion (e.g., coal gasification, biomass co-firing), combustion-based (oxy-fuel combustion and chemical looping combustion), and post-combustion capture. For post-combustion capture, which is the most widely applicable to existing emission sources, three core separation methods are further elaborated: absorption (amine blends, ionic liquids, deep eutectic solvents), adsorption (zeolites, activated carbon, MOFs, COFs, solid amine sorbents), and membrane separation (polymeric, inorganic, and mixed matrix membranes). Key strategies for performance enhancement—such as functionalization, pore engineering, and composite systems—are highlighted. Despite significant advances, large-scale deployment remains challenged by high costs, high energy consumption, and inadequate material stability. Future research should prioritize low-cost, energy-efficient, and robust capture materials and processes to enable net-zero and negative carbon emissions. Full article

The pollution of water, including salt and fresh water, has become an emergency problem. Pollutants come from different sources and have various characteristics, starting from industry and fertilizers used in agriculture, sewage related to human living, and other sources. Diverse sources of pollution require a comprehensive approach to water purification. One possible approach may be the use of appropriate sorbents. Currently, one of the most promising materials used is zeolites. This is because they can come from various sources, including waste raw materials such as fly ash, and, therefore, allow for the use of a circular economy approach. Moreover, these materials can be modified, which enables their selective use for selected types of pollutants. Eventually, these materials become economically viable options. The main aim of this article is to present and analyze possible solutions to water pollution based on zeolite materials. For this purpose, a critical literature review was prepared. The review reveals that zeolites perform particularly well in ion-exchange-driven removal of inorganic contaminants, while their effectiveness for organic micropollutants under realistic conditions is often limited. The identified trade-offs between removal efficiency, regeneration stability, and scalability indicate that zeolites are best applied as function-specific rather than universal sorbents. From a sustainability perspective, this targeted applicability is supported by advantages, such as low material cost, long service life, and the possibility of using naturally occurring or waste-derived precursors, which, together, enable resource-efficient water treatment processes, reduced reliance on energy-intensive technologies, and the valorization of industrial byproducts within circular economy frameworks. Full article

Repurposing mineral processing waste offers both environmental and economic benefits, reducing the disposal burden while enabling mineral resource recovery. A magnetic adsorbent, with an Fe₃O₄ content of 71.0%, collected from waste copper converter slag was utilized to recover gold (Au³⁺) from chloride solution. The adsorbent was separated from the slag samples by crushing, grinding to an average particle size of 30 μm, and magnetic separation. Batch adsorption experiments were performed to evaluate the effects of pH, contact time, chloride concentration, and initial gold concentration on gold uptake amount. The material recovered over 99% of gold from chloride solution under acidic conditions and in the near-neutral pH range. The gold sorption rate was also relatively fast and over 98% recovery was achieved after just 15 min of contact time. Increasing chloride concentration did not influence gold uptake. Parameter studies and spectrometric analyses suggest that chalcocite (Cu₂S) and metallic copper present in magnetite slag reduced the gold chloride complex to metallic gold. These results suggest that converter magnetite slag is a potentially effective sorbent to recover gold from secondary sources due to its selectivity and low cost. Moreover, gold-loaded magnetite slag can be easily separated from the solution by magnetic separation and then recirculated to the smelting stage of copper processing to recover the deposited gold and other precious metals. Overall, this work highlights a pathway to transform waste into opportunity, reinforcing sustainability in mineral processing operations. Full article

This review analyzes the advances over a five-year period in the development of polymeric sorbents for the purification of aqueous media from key classes of pollutants: hydrocarbons (crude oil, diesel fuel), organic dyes, pharmaceuticals (antibiotics), pesticides, herbicides, volatile organic compounds, and polycyclic aromatic hydrocarbons. Attention is paid to the analysis of structure-property-performance relationships, with an emphasis on comparing materials derived from renewable natural feedstocks (such as cellulose, chitosan, terpenes, vegetable oils, and aloe vera) with synthetic polymers. The analysis reveals that biopolymer-based sorbents exhibit comparable or superior sorption capacities combined with environmental safety, biodegradability, and low cost. The key sorption mechanisms include physical adsorption, hydrophobic interactions, and electrostatic interactions. Despite persisting challenges related to scalability, stability in real-world environments, and the need for efficient regeneration protocols, a convergent approach that combines the advantages of modified natural polymers and functional synthetic components appears to be the most promising strategy for developing cost-effective and sustainable technologies for the restoration of water quality. Full article

The aim of this study was to produce and characterize a magnetic biocomposite based on aspen biochar, sodium alginate, and Phaffia rhodozyma yeast biomass, as well as to evaluate its suitability for removing methylene blue (MB) from aqueous solutions. The sorbent structure was confirmed by FTIR, XRD, and SEM, demonstrating successful immobilization of biotic components in an amorphous polymer matrix. Kinetic studies demonstrated a rapid process, with dynamic equilibrium established after 180 min. Experimental data from equilibrium studies (3 h and 24 h) were analyzed using the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models. The theoretical maximum sorption capacity (q_d) determined was 39.31 mg/g, with higher sorption values observed for 24 h confirming the contribution of intrapore diffusion and yeast biosorption activity. In temperature-effect studies, the highest process efficiency (q_e = 1.43 mg/g) was observed at 25 °C, while its decrease at 35 °C indicated the exothermic nature of the phenomenon and the thermal sensitivity of the biological structure. VSM analysis revealed superparamagnetic properties of the composite (Ms = 9.3 A·m²/kg), which enabled full phase separation. Regeneration studies demonstrated that despite the high efficiency of mineral acids, the use of ethanol as an eluent allows for maintaining the structural integrity of the sorbent and its effective use in at least four cycles. The results indicate that the developed biocomposite is a promising, low-cost, and easily recoverable alternative to conventional sorbents in industrial wastewater treatment technologies. Full article

Ammonium nitrogen (NH₄⁺-N) is a key biogenic pollutant in aquatic systems. This study evaluated natural diatomite (Aktobe region) and zeolite (Shankhanai, Zhetysu region) as low-cost, environmentally benign sorbents for NH₄⁺-N removal, and examined the effects of thermal (200–750 °C; 450 °C selected) and alkaline (0.5 M NaOH) treatments on their structural, textural and adsorption properties. Materials were characterized by XRD, XRF, FTIR, SEM-EDX and adsorption performance was assessed by kinetic and equilibrium experiments. Specific surface area and pore characteristics were determined from low-temperature nitrogen adsorption–desorption measurements, and the specific surface area was calculated using the Brunauer–Emmett–Teller (BET) method. Thermal treatment at 450 °C increased the specific surface area of diatomite (46.3 m²/g) and pore volume, and subsequent alkaline activation further enhanced adsorption activity. The modified diatomite achieved up to 84.6% removal of NH₄⁺-N with an equilibrium capacity q_max = 1.758 mg/g. Adsorption kinetics were best described by the pseudo-second-order (PSO) model, which may indicate a substantive role of surface chemical interactions. Equilibrium data were fitted with Langmuir and Freundlich models: the modified diatomite fitted Langmuir best (R² = 0.999), which may suggest predominance of a monolayer adsorption mechanism under the studied conditions, whereas natural samples and the zeolite were better described by the Freundlich model, reflecting likely surface energetic heterogeneity. Separation factor values (R_L = 0.068–0.643) indicate favorable adsorption within the investigated concentration range. The point of zero charge (pHpzc) was determined for all sorbents (5.3–6.3), confirming that at pH 7 the surface carries a negative charge favorable for electrostatic attraction of NH₄⁺ cations. Reusability tests over five consecutive adsorption–desorption cycles showed that modified diatomite and modified zeolite retained 93.4% and 92.3% of their initial removal efficiency, respectively, indicating acceptable stability under the applied regeneration conditions. These results demonstrate the potential of alkaline-modified diatomite and zeolite as effective sorbents for ammonium removal from wastewaters, contributing to the mitigation of eutrophication risks. Full article

Pharmaceutical residues in aquatic environments represent a significant pollution concern, particularly in regions experiencing rapid healthcare and industrial growth. This study presents a sensitive and environmentally sustainable analytical method for monitoring paracetamol (PAR), ibuprofen (IBU), and diclofenac sodium (DIC) in pharmaceutical wastewater from Al-Kharj Governorate, Saudi Arabia. The method integrates off-line solid-phase extraction (SPE) with field-amplified sample stacking (FASS) prior to capillary electrophoresis (CE), enabling effective dual preconcentration and enhanced detection sensitivity. Key parameters affecting separation and enrichment, including background electrolyte composition, pH, injection conditions, stacking efficiency, and SPE sorbent selection, were systematically optimized. Under optimal conditions, the SPE–CE–FASS method demonstrated excellent linearity (r² ≥ 0.997) over the concentration range of 10–1000 ng L⁻¹, with strong precision (intra- and inter-day RSD ≤ 6%) and high recoveries (91.8–98.5%) in pharmaceutical wastewater samples. Matrix-based limits of detection were 4.0 ng L⁻¹ for PAR, 3.5 ng L⁻¹ for IBU, and 3.0 ng L⁻¹ for DIC. The method was successfully applied to real wastewater samples, where all target analytes were detected at environmentally relevant concentrations. Owing to its low solvent consumption, reduced waste generation, and high sensitivity, the proposed SPE–CE–FASS method offers a reliable, cost-effective, and environmentally friendly approach for routine monitoring of pharmaceutical residues in complex wastewater matrices. Full article

The release of CO₂ gas into the atmosphere is one of the most prolific causes of global climate change. To solve this problem, cost-effective technologies are being sought. Polymer membranes are innovative materials that can be widely used in the process of capturing and separating CO₂ gas. In this work, an amine impregnated and amidated solid sorbent (AISS) containing a copolymer (PMMA-co-AA), which consists of acrylic acid (AA) and methyl methacrylate (MMA), and PEPA (polyethylene polyamine), was synthesized. For the first time, sorbents based on homopolymers and copolymers of acrylic acid and methyl methacrylate were compared for their ability to capture CO₂ gas. Other than the synthesis of low swelling AISS, a calculation of its energy consumption, and a comparison of its cyclic capacity with 30% water solutions of monoethanolamine and methyldiethanolamine (MEA and MDEA) were performed. The solid sorbent PMMA-co-AAS showed a higher cyclic capacity than others, corresponding to the order PMMA-co-AAS (23 mg/g) > PAAS (16 mg/g) > MDEA (10 mg/g) > MEA (6 mg/g). The average absorption rate for these sorbents was in the sequence of MEA > PMMA-co-AAS > PAAS > MDEA at 40 °C, and the desorption rates were PMMA-co-AAS > PAAS > MDEA > MEA for these sorbents at 70 °C, correspondingly. When the amount of acrylic acid in the copolymer was varied from 0 to 100%, the copolymer’s water absorption capacity ranged from 0.2 to 1359.63%. Among them, the swelling ability of the chosen sorbent prepared from the 10% AA-containing copolymer and PEPA was 0.64%. Full article

This study investigated the application of apricot stone, an agro-industrial by-product, as a sustainable biosorbent for the removal of Zn ions from aqueous solutions and industrial galvanic wastewater. The equilibrium data conformed well to the Sips isotherm model, indicating heterogeneous sorption behavior, and revealed a maximum sorption capacity of 58.2 mg/g. The biosorbent exhibited a high initial removal efficiency of 95% in aqueous Zn solutions, while its performance in real industrial wastewater was reduced to 55%, due to matrix interference. Ecotoxicological test using seed germination assays revealed no phytotoxic effects from the Zn-loaded sorbent. These findings demonstrate that apricot stone is an effective, low-cost, and environmentally friendly sorbent with significant potential for application in Zn-contaminated water treatment systems, contributing to circular economy and waste valorization initiatives. Full article

Methane (CH₄) is the second-largest contributor to climate change after carbon dioxide (CO₂) and has a global warming potential about 72 times greater than CO₂ over a 20-year timescale. A possible solution to mitigate CH₄ emissions from diluted sources is direct removal of CH₄ through tailored sorbents. In this work, ion-exchanged zeolites have been investigated, owing to their low cost, excellent chemical stability, and ease of production. The impact of barium, lithium, and nickel exchange was investigated, along with one, three, and five ion-exchange sequences. XRD analysis confirmed that the structure remained intact after ion exchange. However, nitrogen physisorption revealed that nickel- and barium-exchanged zeolites had reduced pore volume and surface area compared to the parent zeolite, possibly due to mesopore formation from lattice strain relaxation. ICP-OES and SEM-EDX confirmed the successful incorporation of metals into the zeolite. Finally, breakthrough experiments were carried out to assess the saturation capacity of the synthesized sample. The results demonstrated that the lithium-exchanged samples provided the highest saturation capacity, namely 1.58 ± 0.05 mmol g⁻¹ for the Li-13X-3 and 1.76 ± 0.07 mmol g⁻¹ for the Li-SAPO34-5 over 10 adsorption cycles. Furthermore, the stability of the Li-SAPO34-5 was confirmed over 100 adsorption cycles. Full article

One of the major current societal challenges concerns the reuse of waste materials and valuable substances to mitigate the environmental impact of human activities, which has led to the increasing release of pollutants, from plastics to pharmaceuticals. In this study, we report a simple recycling strategy for surgical masks to obtain an activated carbon-like material, suitable for the solid-phase extraction (SPE) of Phthalic acid esters (PAEss) from plastic bottled water. The sorbent was produced by high-temperature calcination after sulfuric acid treatment to enhance the thermal stability of polypropylene. The sorbent was characterized by thermal analysis, Raman spectroscopy, FTIR and scanning electron microscopy. SPE was used to preconcentrate the analytes, and the main parameters affecting the extraction, such as pH, sorbent amount, organic modifier percentage, ionic strength and elution volume, were optimized. PAEs were determined by UHPLC-PDA under gradient elution. The developed method was linear in the range 0.25–1000 ng/mL, with LOQs between 0.25 and 0.10 ng/mL and LODs between 0.008 and 0.003 ng/mL. Recovery ranged from 95.9 to 104.7%, the precision expressed as RSD% was below 7.32, and the accuracy expressed as BIAS% ranged from −5.75 to 5.93. The proposed approach provides a simple and low-cost valorization route for PPE waste, while enabling reliable PAEs analysis in drinking water. Full article

Heavy metal pollution remains a global environmental challenge, calling for sustainable and low-cost sorbents. Here, we upcycle coir fiber into a bioinspired adsorbent by depositing a polydopamine (PDA) coating (PDA/Coir fiber) for efficient Cu(II) and Cd(II) removal from water while improving effluent safety. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA) confirm successful PDA functionalization and associated structural changes. Compared with pristine coir fiber, PDA/Coir fiber shows 6.84-fold and 12.86-fold higher adsorption capacities for Cu(II) and Cd(II), respectively. Adsorption is well described by the Langmuir isotherm, indicating monolayer-dominated binding. Kinetic analysis shows that the adsorption of both ions follows the pseudo-second-order model. The fiber also exhibits good reusability over four adsorption–desorption cycles. Importantly, cytotoxicity assays of the treated solutions show substantially reduced biotoxicity after metal removal. Overall, PDA/Coir fiber offers a sustainable and low-cost platform for heavy metal removal by integrating efficient adsorption capabilities and safety implications. Full article