Search Results (2,435)

Chloride ions in zinc refining accelerate equipment corrosion and anode and cathode losses, increase lead content, and reduce zinc quality. Therefore, the removal of chloride ions has become a research priority. The existing copper slag dechlorination process has problems such as the solid film barrier leading to impeded mass transfer, product wrapping triggering active site coverage, and incomplete reactions due to insufficient reaction-driving force, leading to low utilization of copper slag, poor dechlorination efficiency, and long reaction times. To address these issues, a new method of deep dechlorination based on the reduction of Cu²⁺ by liquid-phase mass transfer is proposed in this paper. The process utilizes ascorbic acid as a reducing agent, establishes a homogeneous aqueous phase reaction system, breaks through the solid membrane barrier, and avoids the encapsulation of the product layer, achieving efficient dechlorination. The enol structure of ascorbic acid promotes rapid dechlorination through proton-coupled electron transfer (PCET). Thermodynamic calculations show that compared to the current copper slag dechlorination process, this method increases the reaction-driving force by 18.6%, reduces the Gibbs free energy (ΔG^θ) by 59.3%, and increases the equilibrium constant by 6.7 × 10⁹ times, making the reaction more complete and achieving a higher degree of purification. The experimental results show that under optimized conditions, the chloride ion concentration in the solution decreases from 1 g/L to 0.0917 g/L within 20 min, with a removal rate of 90.8%. The main precipitate is CuCl. This process provides a more efficient solution to the chloride ion contamination problem in the hydrometallurgical zinc refining process. Full article

Extreme precipitation events are one of the common hazards in eastern Texas, generating a large amount of storm water. Water running off urban areas may carry non-point source (NPS) pollution to natural resources such as rivers and lakes. Urbanization exacerbates this issue by increasing impervious surfaces that prevent natural infiltration. This study evaluated the efficacy of rain gardens, a nature-based best management practice (BMP), in mitigating NPS pollution from urban stormwater runoff. Stormwater samples were collected at inflow and outflow points of three rain gardens and analyzed for various water quality parameters, including pH, electrical conductivity, fluoride, chloride, nitrate, nitrite, phosphate, sulfate, salts, carbonates, bicarbonates, sodium, potassium, aluminum, boron, calcium, mercury, arsenic, copper iron lead magnesium, manganese and zinc. Removal efficiencies for nitrate, phosphate, and zinc exceeded 70%, while heavy metals such as lead achieved reductions up to 80%. However, certain parameters, such as calcium, magnesium and conductivity, showed increased outflow concentrations, attributed to substrate leaching. These increases resulted in a higher outflow pH. Overall, the pollutants were removed with an efficiency exceeding 50%. These findings demonstrate that rain gardens are an effective and sustainable solution for managing urban stormwater runoff and mitigating NPS pollution in eastern Texas, particularly in regions vulnerable to extreme precipitation events. Full article

To study the chloride transport properties of urban rail transit structures under the action of stray currents, electrochemical tests were employed as part of this paper to investigate the impact of stray currents on cementitious materials and pore structure and further analyze the chloride distribution of specimens in different conditions. Results show that a stray current accelerates calcium ion precipitation in chloride solutions, reducing calcium hydroxide content compared to unelectrified specimens. This dissolution alters the concrete pore structure, increasing porosity by 26.3%, 31.2%, and 36.1% for specimens electrified at 50 mA, 100 mA, and 150 mA, respectively, after 28 days. The effect coefficient k_p of stray currents on the porosity of concrete is given with the test results. Electrified specimens have a higher chloride content compared to unelectrified specimens, with free chloride increasing more than bound chloride as current and time increase. The chloride ion binding capacity of concrete electrified at 150 mA is only 60% that of unelectrified, indicating the significant weakening effect of stray currents on it. Full article

With the continuous development of the potash industry in salt lakes, the preparation of low-natrium salt for the green and environmentally friendly utilization of potassium and sodium resources in salt lakes has become a research hotspot. The primary method involves obtaining potassium brine from salt-lake brine through evaporation and then subjecting this mineral to transformation crystallization to obtain low-natrium salt crystals. In the crystallization vessel, a potassium−sodium-saturated solution is introduced, followed by the addition of an appropriate amount of water and solid magnesium chloride. After a thorough reaction, the solid−liquid separation yields the target product of low-natrium salt. Subsequently, the surface properties of KCl and NaCl crystals were calculated using first-principles methods. The research findings revealed that potassium chloride crystals, when they contained defects, readily adsorbed Na⁺ and NaCl. In a sodium−potassium-saturated system, KCl and NaCl easily formed heterojunctions, leading to embedded crystallization as the Mg²⁺ concentration increased in this saturated system. Feed rate and residence time directly affect the purity of low-natrium salt. A low-natrium salt meeting the requirements can be obtained after a residence time of more than 80 min under the following conditions. Full article

Developing scaffolds with a three-dimensional porous structure and adequate mechanical properties remains a key challenge in tissue engineering of bone. These scaffolds must be biocompatible and biodegradable to effectively support osteoblastic cell attachment, metabolic activity, and differentiation. This study successfully fabricated a chitosan–bacterial cellulose (CS–BC) composite scaffold using the solvent casting/particle leaching (SCPL) technique, with NaOH/urea solution and sodium chloride crystals as the porogen. The scaffold exhibited a well-distributed porous network with pore sizes ranging from 300 to 500 µm. Biodegradation tests in PBS containing lysozyme revealed a continuous degradation process, while in vitro studies with MC3T3-E1 cells (pre-osteoblastic mouse cell line) demonstrated excellent cell attachment, as observed through SEM imaging. The scaffold also promoted increased metabolic activity (OD values) in the MTT assay, and enhanced alkaline phosphatase (ALP) activity and upregulated expression of osteogenic-related genes. These findings suggest that the CS–BC composite scaffold, fabricated using the SCPL method, holds great potential as a candidate for bone tissue engineering applications. Full article

Issues encompassing hazardous waste management face challenges, particularly those involving the manufacture of electronic devices such as PCBs that are in high demand with continual growth. Therefore, upcycling to create new products viable for highly valued markets emphasizes alternative solutions towards the circular economy. This research highlights the advantages of copper sulfate recovery from the cupric chloride etching waste solution from PCB manufacturing, combined with the synthesis of copper nanoparticles for antibacterial application. First, aluminium cementation, sulfuric acid leaching, and crystallization were incorporated in the recovery step to ensure a high purity of 99.95% and a recovery of 94.76%. Aluminium cementation selectively offered copper-containing precipitates suitable for leaching to gain high-purity recovered products. In the second step, copper nanoparticles were synthesized using 0.01–0.20 M copper sulfate precursors via sonochemical reduction. In total, 1–5 mL of hydrazine and 5–30 mL of 0.01 M ethylene glycol were added into a 50 mL precursor as reducing and capping agents, respectively. Hydrazine addition under high pH played a key role in controlling the shape, size, and purity of the copper nanoparticles, required for their antibacterial properties. The optimum condition gave spherical or polygonal copper nanoparticles of 54.54 nm at 99.95% purity and >92% recovery. The antibacterial test of the synthesized copper nanoparticles using E. coli via agar well diffusion exhibited a zone of inhibition (ZOI) of 50 mm at 127 mg/mL, similar to the antibiotic-controlled condition, proving their antibacterial potential. Along with process effectiveness, a feasibility study of the inventing process confirmed the environmental and economic impacts of minimizing energy consumption and processing time, which are competitive with respect to the existing recycling technologies. Full article

This study investigates efficient dehydration and solidification techniques for waste mud generated from loess pile foundations during highway construction in Lanzhou, Northwest China. The waste mud, characterized by high viscosity (85% moisture content) and alkalinity (pH 11.2), poses environmental risks if untreated. Dehydration experiments identified an optimal composite flocculant mixture of 3.5 g polyaluminum chloride (PAC) and 22 mL anionic polyacrylamide (APAM) per 500 mL waste mud, accelerating sedimentation and reducing the supernatant pH to 8.65, compliant with discharge standards. Solidification tests employed a composite curing agent (CG-T1+cement), demonstrating enhanced mechanical properties. The California Bearing Ratio (CBR) of the solidified sediment reached 286%, and the unconfined compressive strength (UCS, 7-day) exceeded 2.0 MPa, meeting roadbed specifications. The combined use of PAC-APAM for dehydration and CG-T1–cement for solidification offers an eco-friendly and economically viable solution for reusing treated waste mud in construction applications, addressing regional challenges in mud disposal and resource recovery. Full article

The optical detection of thioacetamide was investigated using a metalated porphyrin, Mn(III)-5,10,15,20-tetrakis-(3,4-dimethoxyphenyl)-21H,23H-porphyrin chloride (Mn-3,4-diMeOPP), a gold colloid solution (AuNPs), and a complex formed between them (Mn-3,4-diMeOPP–AuNPs) in order to select the most sensitive material and to achieve complementarity between methods. Mn-3,4-diMeOPP, AuNPs, and their complex were synthesized and characterized by means of UV–Vis, FT-IR spectrometry, and AFM investigations. It could be concluded that Mn-3,4-diMeOPP could detect/quantify thioacetamide (TAA) in the range 3.13 × 10⁻⁸ M–7.67 × 10⁻⁷ M in a linear fashion, with a 99.85% confidence coefficient. The gold colloidal particles alone could detect TAA in an extremely narrow concentration domain of 2–9.8 × 10⁻⁷ M, slightly complementary with that of Mn-3,4-diMeOPP. The complex between Mn-3,4-diMeOPP and gold colloid proved to be able to quantify TAA in the trace domain with concentrations of 1.99 × 10⁻⁸ M–1.76 × 10⁻⁷ M in a polynomial fashion, with the method being more difficult. A potential mechanism for TAA detection based on Mn-3,4-diMeOPP is discussed based on computational modeling. The distorted porphyrin conformation and its electronic configuration favor the generation of a grid of electrostatic interactions between porphyrin and TAA. Full article

Due to the lack of skin donors, the short time frame for conducting the procedure, and the increasing demand for tissue specimens, the proper storage conditions for skin fragments have gained critical importance. Therefore, the search for methods for storing skin tissue long-term, ensuring its physiological functions, is a matter of considerable interest. Freezing skin fragments in a cryoprotectant solution, such as dimethylsulfoxide (DMSO), can be a valuable complement to tissues for transplantation and for supplying difficult-to-heal wounds. This study aimed to assess the effect of deep freezing rabbit skin fragments immersed in a 5% DMSO solution on their electrophysiological parameters. Control (n = 23) and defrosted skin specimens were incubated in Ringer (n = 21), amiloride (n = 26), and bumetanide (n = 24) solutions. Then, resistance (R), potential difference (PD), and minimal and maximal PD were measured. The specimens did not show differences in R values compared to controls, which means that the skin subjected to freezing was compact and durable. However, the tissue subjected to freezing in DMSO solution presented increased transport of sodium and chloride ions, which may translate into a change in pain perception, the development of hypersensitivity and/or allergy, and the initiation of repair and regeneration processes. Full article

In this paper, polymer inclusion membranes (PIMs) were created using poly(vinyl chloride)-based alkyl sulfonic acid derivatives as ion carriers and dioctyl terephthalate as a plasticizer for the selective separation of Pb(II), Cu(II), and Cd(II) ions from aqueous nitrate solutions. The ion carriers were dinonylnaphthalenesulfonic acid (DNNSA) and nonylbenzenesulfonic acid (NBSA). The influence of the carrier and the plasticizer concentration in the membrane on the transport efficiency was investigated. For the PIM system, 15% wt. of carrier (DNNSA, NBSA), 20% wt. of plasticizer, and 65% wt. of polymer poly(vinyl chloride) PVC were the optimal proportions, with which the process was the most effective. Research on the transport kinetics has shown that the transport of Pb(II) ions through PIMs containing acidic carriers adheres to a first-order kinetics equation, which is characteristic of a facilitated transport mechanism. The activation parameter for these processes suggests that the high performance of these ion carriers is associated with the immobilization of the carrier within the membrane. It was found that PIMs based on DNNSA facilitate the selective separation of Pb(II)/Cu(II) and Pb(II)/Cd(II) mixtures, achieving high separation factors. Full article

The microencapsulation of bioactive compounds from rapeseed oil using sodium alginate, in the presence and absence of an ultrasonic (US) field, is reported. A Box–Behnken experimental design is used to investigate the influence of process parameters on the microencapsulation yield; then, the response surface methodology is applied, to find their values ensuring its optimum yield. The operating parameters investigated are the ratio of sodium alginate to rapeseed oil, the microencapsulation time and the concentration of the calcium chloride solution. The US bath was used at its nominal power, and the microencapsulation temperature was kept at 20 °C, with a thermostat, for all experiments. A detailed study on the comparison of the two microencapsulation techniques (in the presence and absence of the US field) was carried out. Good results were obtained in the presence of the US field for optimal conditions, when the microencapsulation yield was 90.25 ± 0.02%, higher than the microencapsulation process performed in the absence of the US field, 87.11 ± 0.02%. The results also showed that the use of the US field (optimal conditions) led to an increase in encapsulation efficiency, total phenolic content and antioxidant capacity (76.56 ± 0.02%, 324.85 ± 0.01 mg GAE/g and 57.05 ± 0.12 mg/mL). The physicochemical description of microcapsules was performed using modern characterization methods. These results indicate that by increasing the microencapsulation yield of bioactive compounds through sonication, the process aims to achieve a uniform size distribution of microcapsules. Full article

Potassium chloride (KCl) is the main source of potassium (K) in Brazilian agriculture, but its high import dependency and the need for split applications increase costs and expose the system to supply and efficiency risks. Understanding the availability and release kinetics of potassium (K) from biochar-based fertilizers (K-BBFs) is crucial for optimizing their use as full or partial substitutes for KCl in Brazilian agriculture. This study evaluated biochars derived from banana peel (BP), coffee husk (CH), and chicken manure (CM), both in their pure form and co-pyrolyzed with KCl (composites) at 300 °C and 650 °C, as K sources for corn grown in two contrasting Oxisols. For pure biochars, feedstock type and pyrolysis temperature significantly influenced K content and release kinetics. Higher pyrolysis temperatures increased K content in BP and CH biochars but not in CM, while also slowing K release in CH and CM. Co-pyrolysis with KCl increased biochar yield, ash content, and K availability. Composites released more K than pure biochar but less than KCl, and at a slower rate. Notably, banana peel biochar co-pyrolyzed with KCl at 650 °C (CBP650) exhibited 36% slower K release and reduced KCl use by 82% while maintaining similar K use efficiency and corn growth. All K-BBFs matched KCl in promoting robust corn growth in clay soil, increasing biomass by 5.3 times and K uptake by 9 times compared to unfertilized (no K addition) plants. In sandy Oxisol, K-BBFs boosted biomass by up to 3.5 times compared to unfertilized plants, though some pure biochars were less effective than KCl in supporting full corn growth. Soil texture strongly influenced K availability, with sandier soils exhibiting higher K levels in solution. These findings suggest that kinetic release studies in abiotic systems, such as lysimeters with sand, are not suitable for evaluating K-BBFs as slow-release fertilizers. Due to lower K retention in sandy soil and solution K levels exceeding 1100 mg L⁻¹, split applications of some K-BBFs are recommended to prevent corn cation uptake imbalances and soil K leaching. Additionally, granulating biochar–KCl composites may enhance K retention and regulate its release in sandy Oxisols. Full article

Background/Objectives: The main objective was to evaluate and compare the antifungal efficacy against Candida spp. in commercially available mouthwashes distributed in the European market. Indeed, the solution to emerging infectious diseases may no longer lie in costly new drug development but rather in unlocking the untapped potential of existing substances. Materials and Methods: Eighteen mouthwashes, chosen based on their composition, were tested in vitro against ten Candida strains, including clinical isolates of oral origin and reference strains, in both planktonic and biofilm forms. The antifungal susceptibility testing was conducted using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disc diffusion method and the evaluation of the kinetic growth in planktonic Candida. Biofilm reduction was determined by the evaluation of the minimal biofilm eradication concentration (MBEC). Scanning electron microscopy (SEM) analysis was performed to evaluate potential morphological alterations of Candida biofilms. Results: Most mouthwashes effectively reduced biomass production and colony-forming unit (CFU) count. Parodontax Extra showed the highest efficacy. In the disc diffusion assay, Gum Paroex 0.12% exhibited the largest average inhibition zone diameter. Some unusual trends in the data may be explained by a higher reaction of fungal cells and the release of excess biomass during co-incubation in higher concentration of mouthwashes. SEM images revealed significant morphological alterations. Conclusion: Mouthwashes containing chlorhexidine digluconate, either alone or in combination with cetylpyridinium chloride and other active compounds, emerged as a common factor among the most efficacious formulations. In vivo studies will be essential to validate these findings, but mouthwashes may serve as a valuable adjuvant in the treatment of oral candidiasis. Full article

When testing the output of piezoelectric devices under different pressures, the friction between the pressure platform and the device causes a large amount of frictional electrical signals to be mixed in the output piezoelectric signal, seriously affecting the measurement accuracy of the piezoelectric signal. The current solution is to encapsulate the contact interface with identical materials to suppress triboelectric interference. However, this work has shown that even when contact separation is implemented at the interface of same media, triboelectric signals can still be generated. The heterogeneous potential distribution of the same material in contact separation has been discovered for the first time through the contact interface potential distribution, proving that charge transfer still exists between the same materials. Atomic force microscopy (AFM) was used to analyze the microstructure of the interface, and it was found that the existence of the surface tip structure would enhance the electron loss. Based on this, a new electron transfer model for surface–tip electron cloud interaction is proposed in this work. In addition, by comparing the output voltage characteristics of the triboelectric nanogenerators (TENGs) of seven polymer materials (e.g., polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyimide (PI), and polyethylene terephthalate (PET)), it was found that the open circuit voltage of PP material was only 0.06 V when they friction with each other, which is 2–3 orders of magnitude lower than other materials. When PP materials are applied to the package of piezoelectric devices, the precision of piezoelectric output characterization can be improved significantly, and a new experimental basis for a triboelectric theory system can be provided. Full article

Wastewater from soap production often contains high levels of organic pollutants, exceeding regulatory discharge limits and posing significant environmental concerns. This study investigates a two-stage treatment approach integrating ferric chloride (FeCl₃)-based coagulation–flocculation with membrane filtration to enhance wastewater purification efficiency. This method is one of the appropriate treatment techniques to reduce water pollution. Thus, numerous Jar test trials have been carried out in order to determine the optimal conditions and parameters that make it possible to reduce suspended solids. Key water quality parameters, including chemical oxygen demand (COD), pH, and turbidity, were monitored to assess process performance. Optimization experiments identified optimal coagulation–flocculation conditions, achieving a substantial COD reduction from 9200 mg/L to 351 mg/L significantly improving water quality. However, the treated effluent still failed to meet reuse standards, necessitating further purification. A subsequent membrane filtration stage was implemented, achieving a significant decrease in turbidity to 0.85 Ntu and a turbidity removal efficiency of 99.97%, indicating high treatment efficiency. The final COD of the collected water was 58 mg/L, well below regulatory limits. This hybrid treatment approach offers a highly effective and sustainable solution for soap wastewater management, supporting environmental protection and resource recovery. Full article