Initial Concentration Research Articles

Leveling Up Learning: Game Based Learning Initiatives in Canadian Higher Education

Game based learning (GBL), the use of game design elements within non-game contexts such as education, became increasingly popular in the early 2000s, yet empirical evidence about the benefit of games on student learning remains inconclusive. The potential impact of GBL can be influenced, for example, by design elements, context, and discipline. In Canadian higher education, GBL may be housed within departments, the library, or centres for teaching and learning. At our institution, GBL initiatives have only recently begun to surface; for example, the Department of English and Drama has recently launched a games studies minor for undergraduate students, the library has an extensive collection of video games available to borrow, and the academic skills centre has a large collection of board games that are used primarily for social game cafés. While opportunities for curricular connections may exist, our academic skills centre currently lacks staff who have both capacity and expertise in GBL pedagogy. Exploring possibilities for expansion, we aimed to understand the landscape of GBL initiatives across Canadian post-secondary institutions. To achieve this aim, we conducted an environmental scan of over 100 Canadian post-secondary institutions, gathering data such as the existence of GBL programs, category and level of programming (curricular, co-curricular, or research), initiative types, research development, faculty involvement, and availability of additional resources. Findings indicate inconsistencies in definitions used to promote GBL and a concentration of GBL initiatives at the curricular and research levels. The majority of GBL in Canada is led by faculty through course and degree-level programs at both undergraduate and graduate levels. This research gives us insight into GBL program development, challenges, and opportunities for higher education in Canada and globally.

Fabrication of coconut shell activated carbon filter system for removal of colour and pollutants in textile dye effluent

The present study evaluates the Decolorization and pollutant removal efficiency of chemically impregnated coconut shell-activated carbon using textile dye effluent in the filtration system. The coconut shell zinc chloride activated carbon (CSZAC) was used as a filtering media in wastewater treatment due to its wider pore space with better surface area (590.80 m2 g−1) and higher adsorption capacity. The SEM micrograph revealed that the activated carbon had networks of parallel running pores with internal microstructure and more active sites. The designed activated carbon filter system has dimensions of 90 x 60 x 30 cm; the sections included are the holding tank (50 liters capacity), filtration tank and storage tank with the optimized flow rate of 5 x 10−4 m3 min−1. The Color, pH, EC, TDS, TSS, BOD and COD of textile dyeing wastewater were significantly reduced, after the treatment through the CSZAC filtration system. The initial color concentration of textile dye effluent was 7021 HU and after treatment, the color was fully reduced and became colorless. CSZAC treatment reduced the BOD from 600 mg L−1 to 89.7 mg L−1 (80.6 per cent) and COD from 2500 mg L−1 to 205 mg L−1 (90.5 per cent). Therefore, CSZAC can be used as an effective adsorbent material to remove different dye compounds and pollutants from textile wastewater.

Solidification precipitation behaviour and growth kinetics of AlN inclusions in FeCrAl alloys

AlN inclusions are the major inclusions in FeCrAl alloys and precipitate during solidification. The precipitation behaviour and growth kinetics of AlN inclusions in FeCrAl alloys were theoretically calculated based on the Clyne–Kurz model and a diffusion-controlled growth model. The results indicated that AlN inclusions precipitated at a solid fraction of 0.45. Following precipitation, the Al concentration exhibited a slight decrease compared to scenarios where AlN inclusion precipitation was not considered, although it still showed an increasing trend. Conversely, the N concentration exhibited a significant turnaround, gradually dropping below its initial value. In addition, varying the cooling rate to 0.17, 0.83, 1.67, and 16.67 K/s, the final sizes of AlN inclusions were 46.5, 21.1, 14.8, and 4.7 μm, respectively. Fixing other factors, the solid fractions for AlN precipitation at initial Al concentrations of 4.19, 4.69, and 5.19 wt% were 0.535, 0.45, and 0.365, respectively, and the final sizes of AlN inclusions were 16.2, 14.8, and 13.6 μm, respectively. Similarly fixing the other factors and varying the initial N concentrations to 0.0045, 0.0053, and 0.0060 wt%, the solid fractions of AlN were 0.515, 0.45, and 0.40, respectively, and the final sizes of AlN inclusions were 14.6, 14.8, and 15.0 μm, respectively. This indicates that increasing the cooling rate, increasing the initial Al concentration, and decreasing the initial N concentration could effectively reduce the precipitation size of AlN inclusions. This work provides guidance for the investigation of the precipitation and growth kinetics of AlN inclusions in FeCrAl alloys.

Treatment of Reactive Orange 16 Dye-Bearing Wastewater by Electro-Fenton Process with Stainless-Steel Electrodes: Statistical Optimization and Operational Analysis

Abstract: In the current work, the Electro-Fenton (EF) based Reactive Orange 16 (RO16) dye treatment was studied and compared with central composite (CC) and Taguchi design (TD) statistical optimization tools. Color removal (RC) and COD decay (RCOD) were chosen responses for the effect of pH (A), electrolysis time (B), initial dye concentration (C), and current density (D). The facecentred CC design and L16 orthogonal array were used in the experimental procedures. At optimal conditions, the coefficient of determination (R2) values of 0.99 for CC and 0.97 for TD suggest statistical significance and good model agreement. The results of the ANOVA and Prob. > F values supported the model’s successful experimental data fitting. Taguchi method was found as an appropriate methodology for parameter percentage contributions with fewer experimental runs. Moreover, the S/N ratio charts proved to be a successful CC design replacement. The current density and pH were found to be the most important factors for the EF process. A higher biodegradability (BOD5/COD) and minimum iron concentration (0.45 mg/L) in the effluent sludge demonstrated good environmental disposal suitability. In the last, the effect of various inhibitors/scavengers (SO4 −2, PO4 −3, EDTA, etc.) on the EF process performance was also carried out.

Monocomponent Biosorption of Copper Ions (II) onto Nanocrystalline Cellulose from Coconut Husk Fibers

Introduction: Nanocrystalline cellulose (NCC) is one of the most suitable cellulose derivatives for the treatment of wastewater. Various agricultural wastes have been used for the extraction of NCC. Coconut wastes have been widely studied as potential adsorbents for the removal of pollutants, including dyes and heavy metals. Methods: In this work, nanocrystalline cellulose (NCC) was successfully isolated from coconut husk fibers through alkaline pretreatment accompanied by sulfuric acid hydrolysis. Then, the ability of NCC to adsorb Cu2+ from aqueous solution in batch studies was investigated. Results: Results indicated that the optimal hydrolysis parameters were achieved at 50° C for 45 min with 64% sulfuric acid to extract NCC as rod-like particles with diameters between 4-10 nm. The potential of NCC as a biosorbent to remove copper ions (Cu2+) from aqueous solution was investigated in terms of batch mode and maximum adsorption capacity (qm) of 79.491 mg/g of Cu2+. The adsorption efficiency of Cu2+ions increased with an increase in the adsorbent dosage, decreased with an increase in the initial concentration of contaminant, and increased with the contact time. Under optimal conditions, adsorption kinetic followed a pseudo-second-order kinetic model and the adsorption isotherm fitted most closely with the Langmuir model. Conclusion: According to a literature review, NCC from coconut husk fibers has not been used for the adsorption of heavy metals, mainly copper ions. This study shows that NCC from coconut husk fibers can be used as a low-cost and environmentally friendly adsorbent for the removal of Cu2+ from aqueous solutions.

Adsorptive Sequestration of Methylene Blue Dye from Aqueous Solution Using Novel Roystonea regia fruit Pericarp: Isotherm, Kinetics, and Thermodynamics

The batch adsorptive sequestration of methylene blue from an aqueous solution using unripe Roystonea regia fruit pericarp biomass was investigated in this study. The characteristic nature of the biosorbent was studied using various analytical instruments including Fourier Transform Infra-red spectrophotometer, Scanning Electron Microscope, Energy Dispersive X-ray, X-ray diffractometer, and the Brunauer-Emmett Teller. The adsorption study was perfomed at different experimental conditions including pH, contact time, initial dye concentration, temperature, agitation speed, and biosobent dose. From the results of this study, the optimum biosorption of MB was achieved at 120 min contact time, pH 10, room temperature (298 K), 150 rpm agitation speed and dosage of 100 mg/150 mL dye solution. With 132.30 mgg-1 maximum sorption capacity, the Langmuir isotherm best describes the biosorption equilibrium data. At all initial concentrations, the biosorption kinetics of methylene blue onto the biosorbent fitted best to the pseudo-second order kinetics model, with R2 values ≥ 0.999 and qcal being similar to the qexp. The kinetics study also showed the involvement of intra-particle diffusion in the rate-determining step; although not as the sole limiting step of the sorption process. The results of the thermodynamics study showed the high feasibility, spontaneity, and exothermic nature of the biosorption of methylene blue onto the biosorbent. This study concludes that Roystnea regia fruit pericarp would make an economically viable and renewable biosorbent for practical eco-friendly sequestration of MB dye from wastewaters.

Sorption Efficacy of Weathered Basalt Rock for Metal Ions of Nuclear Importance

Background:: A safe and long-term isolation of radionuclides is crucial for efficient waste management in the nuclear fuel cycle. Clay minerals of geological origin are considered candidate barrier materials for the sequestration of nuclear waste for geological disposal applications. Objective:: The present study encompasses a systematic characterization of weathered basalt rock and the influence of its constituent clay minerals (formed mainly due to the weathering process) in the uptake of metal ions of nuclear importance, such as cesium (Cs+) and strontium (Sr2+). Methods: The structural profile of the weathered basalt has been investigated using different analytical techniques, including polarizing microscope, XRD, FTIR and EDXRF. The sorption behaviour of the rock sample for Cs+ and Sr2+ has been investigated in a comprehensive batch mode by varying the experimental conditions. The analytical findings for structure and batch sorption performance of the material have been further correlated to understand the influence of different parameters on the uptake of metal ions and the underlying mechanism. Results:: Structural analyses confirmed the presence of clay minerals viz., kaolinite, illite and montmorillonite in the sample. A comprehensive sorption performance assessment carried out in batch mode at different experimental conditions revealed that the uptake of both the metal ions was rapid and dependent on initial metal ion concentration and solution pH. The uptake of Cs+ ions was found to be higher as compared to the Sr2+ ions. EDXRF analysis confirmed the loading of Cs+ and Sr2+ on the weathered basalt. Experimental batch sorption data presented a better agreement with the theoretical Freundlich isotherm pertaining to the heterogeneous nature of the sorbent. Conclusion:: The studies highlight that the clay minerals formed by structural alteration of basalt rock upon intense weathering could be very useful in fixing the nuclear fission waste components such as Cs+ and Sr2+.

Adsorption Performance of Acidic Modified Fly Ash: Box–Behnken design

Fly ash (FA) and modified fly ash (mFA) were used as adsorbents to remove methylene blue (MB) dye from aqueous solutions. The adsorbents were characterized using crystal structures with XRD, surface functional groups with FTIR, and surface morphologies with SEM. Response surface methodology (RSM) with Box-Behnken design (BBD) was used to optimize adsorption parameters such as MB dye concentration (A: 10-20 mg/L), solution pH (B: 3-11), and contact time (C: 30-180 min). ANOVA analysis shows the significant inter-actions between initial concentration, solution pH value, and solution pH value, contact time was found to be significant in the removal of MB (p-value=< 0.0001, 0.0040), whereas between the effect of initial concen-tration and contact time was not significant (p-value = 0.0881). The adsorption kinetics followed the pseudo-second-order (PSO) kinetic model and the adsorption isotherm followed the Langmuir model. At 28°C, the adsorption capacity of fly ash-HNO3 for MB was found to be 7.67 mg/g.

Facile synthesis of an acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid copolymer / polyvinylpyrrolidone semi-IPN hydrogel with excellent swelling and anti-leakage properties

Water scarcity becomes an increasingly serious problem for humankind due to climate change and population growth, especially the water leakage in arid and semi-arid areas. Hydrogel polymers show increasingly important roles on water resources utilization. A novel hydrogel copolymer, acrylic acid-co-2-acrylamide-2-methylpropanesulfonic acid copolymer / polyvinylpyrrolidone (P(AA-co-AMPS)/PVP) semi-interpenetrating network (semi-IPN) hydrogel, was designed and successfully synthesized via a facile one-pot free radical copolymerization method. The main parameters during the synthesis process were optimized, including relative contents of polymer monomers, cross-linking agent, initiator and neutralization agent. Physical characterizations demonstrate that, P(AA-co-AMPS)/PVP hydrogel shows porous three-dimensional network structure, including a crosslinked network structure in P(AA-co-AMPS) copolymers and their intermolecular hydrogen bonding interactions with linear PVP. The as-synthesized P(AA-co-AMPS)/PVP hydrogel not only can deliver superior water absorbing capability (up to 1689.95 g g−1) and good reswelling performance, but also shows excellent water anti-leakage performance when being composed with red clay, demonstrating its multi-role applications in future sustainable agriculture.

Effects affecting ammonia removal in synthetic wastewater by locally isolated Rhodobacter sp strain A1

This research focused on the effects affecting ammonia removal in synthetic wastewater by Rhodobacter sp. strain A1 using one factor at a time method (OFAT). Rhodobacter sp. strain A1 are able to remove ammonia from synthetic wastewater due to its ability to assimilate ammonia. The ammonia removal experiment was conducted under different factors; Rhodobacter sp. strain A1 inoculum size (2%, 4%, 6%), incubation temperature (20°C, 25°C, 30°C, 37°C, 40°C), initial pH of synthetic wastewater (5,6,7,8,9) and initial NH4Cl concentration (5 mg/L, 10 mg/L, 15 mg/L) for four days of incubation period. Then, the solution was tested using Nessler reagent which will produce yellow colour when it reacts with ammonia. The intensity of colour is proportional to the ammonia concentration. This experiment was followed by ammonia quantitative analysis via spectrophotometer at 425 nm. The results obtained were then calculated to get the percentage of ammonia removal by PNSB. The result revealed that the bacterium can achieved 97.90 % efficiency of total ammonia removal at optimum growth condition with 6% of inoculum size, incubation temperature at 30°C and initial pH 7. As a conclusion, this Rhodobacter sp. strain A1 can therefore serve as a good candidate in wastewater treatment for ammonia removal.

Mn3O4/ZnO-Al2O3-CeO2 mixed oxide catalyst derived from Mn-doped Zn-(Al/Ce)-LDHs: efficient visible light photodegradation of clofibric acid in water.

Mn3O4/ZnO-Al2O3-CeO2 catalyst was synthesized through a solid-state process from a 3% Mn-doped Zn-(Al/Ce) layered double hydroxide structure. Detailed structural and optical characterization using XRD, FTIR, UV-visible DRS, and TEM was conducted. By investigating clofibric acid (CA) degradation in aqueous solution, Mn3O4/ZnO-Al2O3-CeO2 photocatalytic activity was evaluated. The results show that the heterostructure mixed oxide catalyst has excellent CA photodegradation performance. Further, the characterization reveals that such photocatalytic efficiency can be attributed to two facts that are summarized in the optical properties and the synergic effect between Mn and Ce elements. The sample demonstrated a narrow band gap of 2.34 eV based on DRS. According to the experimental results of the photodegradation, after 120 min of irradiation, the photocatalyst exhibited the highest photocatalytic activity, with a degradation efficiency of 93.6%. Optimization outcomes indicated that maximum degradation efficiency was attained under the following optimum conditions: catalyst dose of 0.3 g/L, initial dye concentration of 20 mg/L, pH 3.86, and 120 min of reaction time. The quenching test demonstrates that photogenerated electrons and superoxide radicals are the most powerful reactive species. The catalyst could be useful in decreasing the photogenerated charges recombination, which offers more redox cycles simultaneously during the catalytic process. The strong Ce-Mn interaction and the formation of their different oxidation states offer a high degradation efficiency by facilitating electron-hole transfer. The introduction of Mn3O4 in the catalyst can effectively improve the visible absorption properties, which are beneficial in the photocatalytic process by reaching a high catalytic efficiency at a low cost.

In English

Purifying aqueous solutions from radioactive contamination is an extremely relevant scientific topic today. Many organic and inorganic adsorbents can be recommended for the adsorption of heavy metal ions and radionuclides from aqueous solutions, or as carriers for storage and disposal of radioactive waste. Since radionuclides are sources of ionizing radiation, the radiation resistance of the adsorbent is an important characteristic. These studies aim to investigate the titanium silicate behavior and its adsorption properties' changes or their invariability in the field of intense β-radiation. Experimental techniques describe the synthesis of titanium silicate adsorbent by sol-gel method and the study of its adsorption capacity toward Ba2+ cations. The adsorption of Ba2+ cations was investigated under batch conditions with neutral pH of the solution. Initial and residual concentrations of Ba2+ cations were controlled by direct complexometric titration with Na-EDTA with Eriochrom Black T as an indicator. The study of the radiation resistance of the adsorbent to high-energy β-radiation was performed using a 90Sr-90Y β- - source “Sirius” installed in the Microtron Laboratory of the Uzhhorod National University. The distance from the source to the adsorbent samples was 20 cm. The flux of electrons at this distance was 108 el/cm2‧per second. The maximum energy of beta particles was 0.456 MeV for 90Sr and 2.28 MeV for 90Y. The maximum duration of exposure was 21 days, which corresponds to 1310 Gy. Raman spectroscopy of irradiated and nonirradiated samples of TiSi was performed using a Raman spectrometer XploRA PLUS installed in the Center for Collective Use of Scientific Equipment “Laboratory of Experimental and Applied Physics” of Uzhhorod National University. Results consist of kinetic of Ba2+ adsorption by titanium silicate and irradiated titanium silicate; isotherm of Ba2+ adsorption and Raman spectrum of nonirradiated, irradiated titanium silicate (TiSi) and TiSi after Ba2+ adsorption. Results showed that the value of the maximal adsorption was 140.5±9.2 mg/g (6.55 %) under a confidence level of 95 %. The adsorption values of barium ions by irradiated and non-irradiated titanium silicate coincide. This indicates that the adsorption properties of this adsorbent do not change under the influence of such a radiation dose. The Raman spectra of irradiated and non-irradiated titanium silicate coincide, while they do not identify free radicals, or ionic formations, which would indicate a change in the properties of the adsorbent under the influence of beta radiation. It can be argued that this adsorbent is radiation-resistant to beta-radioactivity, with a radiation dose of 1310 Gy. The main conclusion of the present work is that the studied sample of titanium silicate is radiation-resistant. It can withstand a radiation dose of 1310 Gy without changing its adsorption properties. Titanium silicate can be used for the adsorption of strontium radionuclides, it can be a carrier for the disposal of radioactive waste.

Investigation and Optimization of Biosorbent Capacities of Some Plants Used in Daily Life

In this study, sage, chamomile, and tarragon leaves, which are used as spices and consumed as beverages in daily life, were considered as different biosorbents that can be used in water purification by biosorption. At the same time, the effects of the parameters of initial dye concentration (10-200 mg/L), temperature (20-50 ⁰C) and contact time (0-120 min) on biosorption capacity were investigated. The biosorption processes were found to follow Freundlich isotherm and pseudo-second order (PSO) reaction kinetics. In the study, the process was also modeled using multi-tree evolutionary computation based automatic programming (AP) methods. The methods used initial dye concentration, temperature, and contact time as variables. According to the simulation results, these methods obtained nonlinear mathematical models of the processes with R^2 values as high as 0.99 for each biosorbent. By providing the most accurate models to accurately predict biosorption capacity, this study will make a significant contribution to the field of water treatment using experimental and AP methods.

Blood Kinetics of Lipophilic and Proteinophilic Pollutants during Two Types of Long-Term Fast in King Penguins.

In vertebrates, fasting is an intricate physiological process associated with strong metabolic changes, yet its effect on pollutant residue variation is poorly understood. Here, we quantified long-term changes in plasma concentrations of 20 organochlorine and 16 perfluoroalkyl pollutants in king penguins Aptenodytes patagonicus during the breeding and molting fasts, which are marked by low and high levels of protein catabolism, respectively, and by strong lipid use. The profile of measured pollutants in plasma was dominated by perfluorooctanesulfonic acid (PFOS, initial relative contribution of 60%). Initial total pollutant concentrations were similar in molting (3.3-5.7 ng g-1 ww) and breeding penguins (range of 4.2-7.3 ng g-1 wet weight, ww). Long-term fasting (25 days) for molting and breeding led, respectively, to a 1.8- and 2.2-fold increase in total plasma pollutant concentrations, although the rate and direction of change were compound-specific. Hexachlorbenzene (HCB) and PFOS concentrations increased in plasma (net mobilization) during both types of fasting, likely due to lipid use. Plasma perfluoroundecanoate (PFUnDA) and perfluorotridecanoate (PFTrDA) concentrations increased in breeders (net mobilization) but decreased in molting individuals (net excretion), suggesting a significant incorporation of these pollutants into feathers. This study is a key contribution to our understanding of pollutant variation in blood during long-term fasting in wildlife.

A synergistic integration of life cycle assessment and response surface methodology to optimize grape stalk waste-based biosorption for effective Cd(II) removal

In order to remove Cd(II) ions from aqueous solutions, this research suggests an in-depth study on a laboratory scale for the efficient and sustainable removal of Cd(II) in aqueous solution using wine industry grape stalk waste. The maximum biosorption capacity that was achieved was 84.74 mg/g for the Langmuir isotherm model. The kinetic studies revealed that the biosorption data were better explained by a pseudo-second order model. By using the response surface method with desirability functions, the optimal variables were determined for three optimization scenarios. The first optimization scenario yielded the highest percentage of cadmium removal, reaching 87.75%. The goal of that scenario was intended to obtain the maximum percentage of cadmium removal while minimizing the cost of the process. In this scenario, the greatest environmental impact was on the marine aquatic ecotoxicity (2.685 kg 1.4 DB eq.) with a power consumption of 27.05 W. Furthermore, the values for the input variables were an initial cadmium concentration of 0.6 mg/l, pH of 7.5, stirring time of 10 min, stirring speed of 100 rpm, a process temperature of 15 °C, and a dose of grape stalk of 0.50 g. The experimental and predicted findings agree. This suggests that grape stalk waste has potential applications as a biosorbent for the removal of Cd(II) ions from aqueous solution.

Biodegradation of a complex hydrocarbon mixture and biosurfactant production by Burkholderia thailandensis E264 and an adapted microbial consortium.

Bioremediation is considered to be an effective treatment for hydrocarbon removal from polluted soils. However, the effectiveness of this treatment is often limited by the low availability of targeted contaminants. Biosurfactants produced by some microorganisms can increase organic compound solubility and might then overcome this limitation. Two different inocula producers of biosurfactants (Burkholderia thailandensis E264 and SHEMS1 microbial consortium isolated from a hydrocarbon-contaminated soil) were incubated in Bushnell-Haas medium supplemented with hydrocarbons to investigate their biodegradation potential. Experimental results showed their ability to degrade 9.1 and 6.1% of hydrocarbons respectively after 65 days of incubation with an initial total hydrocarbon concentration of 16 g L-1. The biodegradation was more effective for the light and medium fractions (C10 to C36). B. thailandensis and SHEMS1 consortium produced surfactants after 14 days of culture during the stationary phase with hydrocarbons as the sole carbon and energy source. However, biosurfactant production did not appear to directly increase hydrocarbon degradation efficiency. The complexity and recalcitrance of hydrocarbon mixture used in this study appeared to continue to limit its biodegradation even in the presence of biosurfactants. In conclusion, B. thailandensis and SHEMS1 consortium can degrade recalcitrant hydrocarbon compounds and are therefore good candidates for the bioremediation of environments polluted by total hydrocarbons.

CdS QDs interspersed onto MOF-808 as adsorptive photocatalyst for efficient visible-light driven degradation of ciprofloxacin

CdS Quantum dots (QDs) anchored onto the surface of MOF-808 (hereafter designated as CdS QDs@MOF-808) were constructed by solvothermal method and applied for degradation of ciprofloxacin (CIP) under visible light irradiation. The impacts of pH values and initial concentrations of CIP on adsorption and photocatalytic activity were explored in detail. The as-prepared CdS QDs@MOF-808 composites showed enhanced synergistic adsorption capacity and photocatalytic properties, especially for the CM-20 sample with 20 % CdS QDs loading exhibiting about 5.2 times adsorption capacity (130 mg/g) and approximately 5.5 times photocatalytic removal rate ( 82 %) for CIP compared with the pristine CdS and MOF-808. Various techniques such as XPS, UV‐vis DRS, Zeta potential, EIS, PL as well as transient photocurrent responses have demonstrated that the synergistic effect of CdS QDs and MOF-808 is ascribed to the enhanced electrostatic interactions and Zr-S forces, improving the utilization of visible light and effectively photogenerated electrons transported from the conduction band of CdS to that of MOF-808. Gas chromatography-mass spectroscopy (GC-MS) was used to detect the possible intermediates in the degradation process of CIP.

Temperature/pH/reduction-sensitive multiple stimulus-responsive nanogels synthesized by one-pot method for design as curcumin carriers

Curcumin (Cur) is of interest due to its widely reported pharmacology, which is limited by its low water solubility and low bioavailability of clinical use. Here, we report the characterization and application of a multiple stimulus-responsive nanogel loaded with Cur. Sensitive P(AM-co-NIPAM) nanogels for pH, temperature, and reduction stimuli were prepared by reflux precipitation polymerization method using AM and NIPAM as raw materials. DLS and SEM analyses showed that the fabricated nanogels had a uniform size distribution with spherical and nucleated-shell structures. By adjusting the feeding amounts of reactive monomers, cross-linkers, and initiators, a series of monodisperse nanogels with different particle sizes could be obtained. The representative nanogels have different Cur-loaded behaviors at different temperatures, times, and initial concentrations of the drug, as well as a sensitive release to changes in pH, temperature, or reducing conditions. Cur-P(AM-co-NIPAM) nanogels showed superior antioxidant activity over the free Cur in vitro. Meanwhile, it inhibited LPS and H2O2-induced oxidative stress, which could effectively inhibit the cellular production of excessive reactive oxygen species and had a protective effect against LPS-induced cellular damage. This nanogel controlled release system significantly improved the safety limit of Cur without hemolytic behavior and had good cytocompatibility. The successful development of such Cur nanogels will lead to advanced materials that can be functionalized and optimized for the controlled delivery of small molecules or biomolecules for targeted therapeutic and biomedical applications.

Uranium accumulation in environmentally relevant microplastics and agricultural soil at acidic and circumneutral pH

The co-occurrence of microplastics (MPs) with potentially toxic metals in the environment stresses the need to address their physicochemical interactions and the potential ecological and human health implications. Here, we investigated the reaction of aqueous U with agricultural soil and high-density polyethylene (HDPE) through the integration of batch experiments, microscopy, and spectroscopy. The aqueous initial concentration of U (100 μM) decreased between 98.6 and 99.2 % at pH 5 and between 86.2 and 98.9 % at pH 7.5 following the first half hour of reaction with 10 g of soil. In similar experimental conditions but with added HDPE, aqueous U decreased between 98.6 and 99.7 % at pH 5 and between 76.1 and 95.2 % at pH 7.5, suggesting that HDPE modified the accumulation of U in soil as a function of pH. Uranium-bearing precipitates on the cracked surface of HDPE were identified by SEM/EDS after two weeks of agitation in water at both pH 5 and 7.5. Accumulation of U on the near-surface region of reacted HDPE was confirmed by XPS. Our findings suggest that the precipitation of U was facilitated by the weathering of the surface of HDPE. These results provide insights about surface-mediated reactions of aqueous metals with MPs, contributing relevant information about the mobility of metals and MPs at co-contaminated agricultural sites.

Removal of Methyl Violet 2B and Direct Black 22 from Single and Binary System Using a Magnetic Zeolite/MgO/Starch/Fe3O4 Nanocomposite

This study focuses on the preparation and characterization of magnetic zeolite (FSM-Zeo) using starch, magnesium oxide, and Fe3O4. Various analyses, including BET, FTIR, SEM, EDS, XRD, Zeta potential, and VSM, were conducted to assess the properties of FSM-Zeo. The adsorption capacity of FSM-Zeo was investigated for methyl violet (MV-2B) and direct black 22 (DB-22) in both single and binary dye solutions. Key parameters such as adsorbent amount, initial dye concentration, contact time, temperature, initial pH, and ionic strength were examined in the single system. Kinetic and isotherm studies revealed that DB-22 and MV-2B adsorption followed the pseudo-second-order model. Moreover, Freundlich and Langmuir models were confirmed for MV-2B and DB-22 adsorption on FSM-Zeo, respectively. In the binary system, the presence of MV-2B enhanced the adsorption of DB-22, resulting in higher removal compared to the single dye solution. A synergistic effect was observed due to the interaction between DB-22 and MV-2B, promoting the adsorption of DB-22 on FSM-Zeo.