Search Results (5,896)

Forward osmosis (FO) technology, known for its minimal energy requirements, excellent resistance to fouling, and significant commercial potential, shows enormous promise in the development of sustainable technologies, especially with regard to seawater desalination and wastewater. In this study, we improved the performance of the FO membrane in terms of its mechanical strength and hydrophilic properties. Generally, the water flux (J_w) of polyisophenylbenzamide (PMIA) thin-film composite (TFC)-FO membranes is still inadequate for industrial applications. Here, hydrophilic polydopamine (PDA)@ zeolitic imidazolate frameworks-8 (ZIF-8) nanomaterials and their integration into PMIA membranes using the interfacial polymerization (IP) method were investigated. The impact of PDA@ZIF-8 on membrane performance in both pressure-retarded osmosis (PRO) and forward osmosis (FO) modes was analyzed. The durability and fouling resistance of these membranes were evaluated over the long term. When the amount of ZIF-8@PDA incorporated in the membrane reached 0.05 wt% in the aqueous phase in the IP reaction, the J_w values for the PRO mode and FO mode were 12.09 LMH and 11.10 LMH, respectively. The reverse salt flux (J_s)/J_w values for both modes decreased from 0.75 and 0.80 to 0.33 and 0.35, respectively. At the same time, the PRO and FO modes’ properties were stable in a 15 h test. The incorporation of PDA@ZIF-8 facilitated the formation of water channels within the nanoparticle pores. Furthermore, the J_s/J_w ratio decreased significantly, and the FO membranes containing PDA@ZIF-8 exhibited high flux recovery rates and superior resistance to membrane fouling. Therefore, PDA@ZIF-8-modified FO membranes have the potential for use in industrial applications in seawater desalination. Full article

Integrating circular economy (CE) principles into mining practices offers a promising path toward reducing environmental harm while promoting sustainable resource management. This shift boosts the industry’s efficiency and profitability and aligns it with global sustainability goals. This paper delves into strategies for closing material loops, such as waste valorization, resource recovery from mine tailings, and water reuse in mining processes. Additionally, this study highlights innovative technologies and their potential to transform traditional linear practices into sustainable, circular systems. This paper emphasizes the importance of strong collaboration among industry stakeholders and policymakers, including mining companies, researchers, and local communities, for the implementation of CE principles. This paper also discusses the role of emerging digital tools, automation, and artificial intelligence in advancing circular practices and improving operational efficiency. By exploring the economic, environmental, and social benefits of the CE, this paper demonstrates how these practices can contribute to sustainable mining. It addresses key challenges, including technological, economic, and regulatory hurdles, and offers recommendations for overcoming them to pave the way for a more sustainable and resilient mining industry. Full article

The direct discharge of cationic surfactants into environmental matrices has exponentially increased due to their wide application in many products. These compounds and their degraded products disrupt microbial dynamics, hinder plant survival, and affect human health. Therefore, there is an urgent need to develop electroanalytical assessment techniques for their identification, determination, and monitoring. In our study, ZnO-PANI nanocomposites were electrodeposited on a glassy carbon electrode (GCE), followed by the immobilization of laccase enzymes and the electrodeposition of polypyrrole (PPy), to form a biosensor that was used for the detection of CTAB. A UV-Vis analysis showed bands corresponding to the π-π* transition of benzenoid and quinoid rings, π-polaron band transition and n-π*polaronic transitions associated with the extended coil chain conformation of PANI, and the presence and interaction of ZnO with PANI and type 3 copper in the laccase enzymes. The FTIR analysis exhibited peaks corresponding to N-H and C-N stretches and bends for amine, C=C stretches for conjugated alkenes, and a C-H bend for aromatic compounds. A high-resolution scanning electron microscopy (HRSEM) analysis proved that PANI and ZnO-PANI were deposited as fibres with hairy topography resulting from covalent bonding with the laccase enzymes. The modified electrode (PPy-6/GCE) was used as a platform for the detection of CTAB with three linear ranges of 0.5–100 µM, 200–500 µM, and 700–1900 µM. The sensor displayed a high sensitivity of 0.935 μA μM⁻¹ cm⁻², a detection limit of 0.0116 µM, and acceptable recoveries of 95.02% and 87.84% for tap water and wastewater, respectively. Full article

Methylene blue is a cationic organic dye commonly found in wastewater, groundwater, and surface water due to industrial discharge into the environment. This emerging pollutant is notably persistent and can pose risks to both human health and the environment. In this study, we developed a Surface Plasmon Resonance Biosensor employing a BK7 prism coated with 3 nm chromium and 50 nm of gold in the Kretschmann configuration, specifically for the detection of methylene blue. For the first time, laccases immobilized on a gold surface were utilized as bio-receptors for this organic dye. The enzyme was immobilized using carbodiimide bonds with EDC/NHS crosslinkers, allowing for the analysis of samples with minimal preparation. The method demonstrated validation with a limit of detection (LOD) of 4.61 mg L⁻¹ and a limit of quantification (LOQ) of 15.37 mg L⁻¹, a working range of 0–100 mg L⁻¹, and an R² value of 0.9614 during real-time analysis. A rainwater sample spiked with methylene blue yielded a recovery rate of 122.46 ± 4.41%. The biosensor maintained a stable signal over 17 cycles and remained effective for 30 days at room temperature. Full article

In the process of oilfield development, the surfactant–polymer (SP) composite system has shown significant effects in enhancing oil recovery (EOR) due to its excellent interfacial activity and viscoelastic properties. However, with the continuous increase in the volume of composite flooding injection, a decline in injection–production capacity (I/P capacity) has been observed. Through the observation of frozen core slices, it was found that during the secondary composite flooding (SCF) process, a large amount of residual oil in the form of intergranular adsorption remained in the core pores. This phenomenon suggests that the displacement efficiency of the composite flooding may be affected. Research has shown that polymers undergo flocculation reactions with clay minerals (such as kaolinite, Kln) in the reservoir, leading to the formation of high-viscosity mixtures of migrating particles and crude oil (CO). These high-viscosity mixtures accumulate in local pores, making it difficult to further displace them, which causes oil trapping and negatively affects the overall displacement efficiency of secondary composite flooding (SCF). To explore this mechanism, this study used a microscopic visualization displacement model (MVDM) and microscopy techniques to observe the migration of particles during secondary composite flooding. By using kaolinite water suspension (Kln-WS) to simulate migrating particles in the reservoir, the displacement effects of the composite flooding system on the kaolinite water suspension, crude oil, and their mixtures were observed. Experimental results showed that the polymer, acting as a flocculant, promoted the flocculation of kaolinite during the displacement process, thereby increasing the viscosity of crude oil and affecting the displacement efficiency of secondary composite flooding. Full article

A convenient, rapid, and environmentally friendly method, emulsive liquid–liquid microextraction combined with high-performance liquid chromatography, was established to determine phthalic acid esters in tap, river, lake, and sea water. After the method’s optimization, we obtained the appropriate volume of the extractant and pure water, the number of strokes, the separation methods, the mass volume fraction of the demulsifier, the demulsifier volume, the sample volume, the salt amount, and the pH conditions. This method requires only 200 μL of heptanoic acid (fatty acid) as the extractant and 75 mg of sodium acetate as demulsifiers for fast microextraction and separation, respectively, avoiding the use of further equipment. Emulsive liquid–liquid microextraction offers substantial advantages over dispersive liquid–liquid microextraction by eliminating the need for toxic dispersants, thereby preventing any influences of dispersants on the partition coefficients. The linear range of detection ranged from 0.5 to 50 μg L⁻¹, with a limit of detection of 0.2 μg L⁻¹ and a limit of quantitation of 0.5 μg L⁻¹. The recoveries ranged from 80.2% to 106.3%, and the relative standard deviations ranged between 0.5% and 6.7%. Five greenness metrics confirmed that this method is environmentally friendly and aligns with the principles of green analytical chemistry. The proposed method achieved a greenness score of 8.42, surpassing that of other methods as evaluated using the SPMS. The novel method may well be a valuable technique for determining phthalic acid esters in water samples. Full article

This study investigates the reactivity of municipal solid waste incineration residues to aqueous carbonation, focusing on CO₂ absorption rates, uptakes, and heavy metal (HM) leachability. Various combinations of boiler, electrofilter, and bag filter residues were assessed under typical incineration conditions. Bag filter residues from lime-sorbent plants exhibited the highest CO₂ uptake (244.5 gCO₂/kg), while bottom ash (BA) fine fraction, boiler/electrofilter fly ash (FA), and other mixed air pollution control residue (APCr) demonstrated uptakes of 101, 0, 93, and 167 gCO₂/kg, respectively. Carbonation kinetics revealed that high calcium content FA and APCr, followed similar CO₂ absorption trends. Notably, BA carbonation was predominantly driven by Ca-aluminates rather than lime. Carbonation reduces leaching of Al, As, Cd, Co, Cu, Ni, Pb and Zn compared to water washing, though significant concerns arise with anions such as Sb and Cr. In BA, critical behaviours of Cr, Mn, and Fe were observed, with Cr leaching likely controlled by Fe-Mn-Cr oxide particle dissolution. These findings highlight the potential of integrating enhanced metal recovery (EMR) through density or magnetic separation in BA prior to carbonation to reduce HM leaching and recycle critical metals (Ag, Cu, Cr, Ni, Mn, etc). Full article

The present work focuses on the recovery of cellulose from mixed fabrics containing polyester and cotton through the use of different chemical and hydrothermal treatment methods. Through the application of various analytical techniques, such as thermogravimetry (TG) and infrared spectroscopy (IR), we seek to determine the effectiveness of the methods used. The results indicate that different treatments with NaOH and distilled water at high temperatures and pressures are particularly effective for the extraction of the cellulose fraction. Furthermore, these methods were compared with previous studies to evaluate their feasibility and sustainability. The findings underline the importance of selecting appropriate experimental conditions to maximize the purity of the cellulose obtained and minimize fiber degradation, thus promoting more efficient and sustainable textile recycling processes. These results have significant implications for industrial applications by enabling the development of scalable recycling methods and contribute to reducing the environmental impact of textile waste. Full article

Dredged material is a common environmental and economic issue worldwide. Tons of highly contaminated material, derived from cleaning the bottoms of bays and harbours, are stored until depuration. These volumes occupy huge extensions and require costly treatments. The Ria of Huelva (southwest Spain) receives additionally high metal contamination inputs from the Odiel and Tinto Rivers which are strongly affected by acid mine drainage (acid lixiviates with high metal content and sulphates). These two circumstances convert the port of Huelva into an acceptor/accumulator of contamination. The current study proposes an alternative active treatment of dredged material and mining residues using ASEC (Adiabatic Sonic Evaporation and Crystallization) technology to obtain distilled water and valuable solid conglomerates. Different samples were depurated and the efficiency of the technology was tested. The results show a complete recovery of the treated volumes with high-quality water (pH~7, EC < 56 µS/cm, complete removal of dissolved elements). Also, the characterization of the dried solids enable the calculation of approximate revenues from the valorization of some potentially exploitable elements (Rio Tinto: 4 M, Tharsis: 3.7 M, dredged material: 2.5 M USD/yr). The avoidance of residue discharge plus the aggregated value would promote a circular economy in sectors such as mining and dredging activities. Full article

This study explores the numerical modeling of CO₂ injection in water within a lab-scale domain, where the dimensions are in the order of centimeters, highlighting its diverse applications and significant environmental and economic benefits. The investigation focuses on the impacts of heterogeneity, capillary pressure, and CO₂ viscosification on water production. Findings reveal that increasing CO₂ viscosity by a factor of 5 drastically influences water production, while further increasing it to a factor of 10 yields minimal additional effect. Capillary pressure notably delays breakthrough and reduces sweeping efficiency (effectiveness of the injected CO₂ in displacing water), with a more pronounced impact in slim cores (1 cm) compared to thick cores (3.8 cm). The numerical modeling of CO₂ injection in water within a lab-scale domain provides valuable insights into enhanced oil recovery (EOR) techniques. These optimized strategies can improve the efficiency and effectiveness of CO₂-EOR, leading to increased oil and gas recovery from reservoirs. Full article

Electrodialysis (ED) has already been applied to recover nickel in galvanizing processes, allowing nickel recovery and the production of a treated effluent with demineralized water quality. However, the growth in ED use is still limited by the production and commercialization of ion-selective membranes, currently limited to a few large companies. Therefore, this paper presents the development of homogeneous cationic and anionic membranes made from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) for ED use. Cationic membranes were prepared by the sulfonation reaction of PPO under different experimental conditions (PPO:H₂SO₄ molar ratio and reaction time). Anionic membranes were prepared by the bromination reaction of PPO, followed by the amination reaction. The membranes were characterized for their chemical and electrochemical properties, including ion exchange capacity, conductivity, thermal stability, and surface morphology. The optimal conditions for cationic membrane sulfonation were achieved with a 1:4.4 PPO:H₂SO₄ molar ratio, and a reaction time of 0.5 h. For anionic membranes, the best results were obtained with bromination, with a PPO:NBS (N-Bromosuccinimide) molar ratio of 1:0.5, followed by 14 days of amination. Overall, 91.8% chloride, 90.9% sulfate, and 85.5% nickel ion extraction was achieved, highlighting PPO as a promising polymer for the development of anionic and cationic ion-selective membranes for ED. Full article

The High-Density Sludge (HDS) process is widely used for the treatment of acid mine water as it produces a sludge of high density. The aim of this study was the development of a process where iron in mine water can be removed as magnetite, to assist with rapid settling of sludge. It was concluded that Fe²⁺ can be removed as Fe₃O₄ (magnetite) by forming Fe(OH)₂ and Fe(OH)₃ in the mole ratio of 1:2. Magnetite can form in the absence or presence of gypsum. The settling rate of magnetite-rich sludge is substantially faster than that of ferric hydroxide-rich sludge. It is recommended that further studies be carried out on the separation of magnetite gypsum through magnetic separation. Full article

Pinus yunnanensis has high economic and ecological value. The survival of P. yunnanensis has been greatly affected by global warming. This study examines the response of P. yunnanensis seedlings to drought stress and their recovery following rewatering, focusing on growth metrics and C:N:P stoichiometry. This experiment included the four following treatments: CK (water content was 90% ± 5%); LS (water content was 75% ± 5%); MS (water content was 60% ± 5%); and SS (water content was 45% ± 5%). This experiment also included a continuous drought period of 30 days followed by 7 days of rewatering. This study found that drought limited the growth of seedlings, and seedlings could recover rapidly from the damage caused by LS and MS treatments after rewatering, and the recovery of seedlings was greater following LS and MS treatments than following SS. After the drought, the C content in the leaves and stems of P. yunnanensis seedlings could recover to CK levels after rewatering. The N content of each organ and the P content of fine roots of P. yunnanensis seedlings showed an upward trend after rewatering. In summary, the growth of P. yunnanensis seedlings was significantly affected by drought stress, and the recovery mechanism of rewatering varied depending on the degree of drought. Combining the phenotypic plasticity index and principal component analysis, the stem biomass, thin root biomass, root/shoot ratio, leaf C:P, leaf N:P, leaf P, stem C:P, thin root N, thin root P, coarse root N, coarse root P, and coarse root C were the most important indexes for adaptation to drought and rewatering. Full article

When a comparison is made between production methods, it will be seen that a significant amount of energy is consumed in machining processes and a large part of this energy is lost as waste heat. This is an important risk factor for both energy efficiency and environmental protection. During metalworking, a very high level of heat is generated at the cutting tool–workpiece interface. We have conducted a comprehensive literature study on this subject, but so far, no study has been found on the recovery of the heat generated in machining processes. Therefore, the aim and motivation of this study is to recover this waste heat to a certain extent. For this purpose, a comprehensive coolant temperature control and heat recovery system has been developed. This system, which was produced as a prototype, can be easily integrated into the machine tool and automatically adjust the coolant temperature to a certain constant temperature level and maintain this temperature value throughout the process. More importantly, it recovers the heat energy taken from the coolant and makes it useful. On the other hand, although it is not the subject of this study, cutting performance increases, coolant consumption decreases and tool life is extended with the cooling of the coolant. Thus, environmental risks are also reduced. Also, the efficiency and economic feasibility of the developed system were also examined. For this purpose, the energy amount consumed by the developed system and the machine tool were measured separately, and the total energy consumed was determined. Then, the consumed and recovered energy amounts were compared, and it was seen that the amount of energy recovered was more than the total amount of energy consumed. When the decrease in coolant and cutting-tool consumption is also taken into account compared to the classical cooling system, it is understood that the amortization period of the developed system is quite low. On the other hand, optimum conditions were investigated in order to provide maximum energy recovery. For this purpose, experiments were carried out by drilling 2592 holes on 27 samples, 96 holes in each sample, by taking the coolant solution ratio, cutting speed, and feed rate as variable parameters. The experimental results were evaluated using the Taguchi method. It has been observed that the system can be easily adapted to other machining processes, such as turning and milling, and that it has a high potential to increase energy efficiency and prevent environmental risks in this area. Full article

Aquifer Storage and Recovery (ASR) can involve injecting available surface water into an unconfined aquifer and then extracting it to provide secondary water for irrigation. This study demonstrates a method for evaluating the appropriateness of steady injection versus unsteady injection for an assumed situation. In design, it can be important to affect the transient: the proportion of the injected water that would be subsequently extracted (versus that remaining in the aquifer) and the proportion within the extracted water that would be an injectate (versus ambient groundwater). These proportions can be predicted from the predicted value of an ASR well’s Recovery Effectiveness (REN)—the time-varying proportion of injectate that is extracted subsequently from the same fully penetrating well. Applying the demonstrated procedure with appropriately detailed data and simulation models can predict the REN values resulting from steady versus unsteady injection, followed by steady extraction. For convenience in displaying and computing REN, the injectate was assumed to have a 100 ppm conservative solute concentration. For this demonstration, a homogenous isotropic unconfined one-layer aquifer was assumed. The scenarios involved steady or unsteady injection for 61 days via a fully penetrating ASR well. Then, 91 days of steady pumping led to the extraction of a total volume equal to that injected. For the assumed hydrogeologic data—31 years of Salt Lake City, Utah, rainfall data and estimated captured runoff—the results show that steady injection is more likely to cause a predictable REN but might not cause a higher REN than daily varying injection of the same total volume. Assuming different runoff or hydrogeologic flows would lead to different REN values. Steady injection causes a predictable groundwater mound and can assure a sufficient vadose zone thickness for overlying plants. Augmentation and storage of captured rainwater can help to provide a steady injection rate. For a situation that requires REN management, appropriate simulations can help water managers design ASR systems that will achieve REN goals and increase sustainable groundwater availability. Full article