Mixed System Research Articles

AsIII-enhanced oxidation by coexisting MnIII-phenolic complexes during arsenic contaminated groundwater treatment by MnO2

Manganese oxides (MnO2) are widely utilized in arsenic(AsIII)-contaminated groundwater remediation; however, As(III) oxidation is greatly affected by co-occurring substances. This study discusses the oxidation pathways of As(III) oxidation-adsorption in presence of co-solutes (e.g., Mn(II), Fe(II), and 2,4-dichlorophenol (DCP). Mn(II) species competed with As(III) for adsorption and oxidation sites at MnO2 surface, resulting in a decrease in As(III) removal. As(III) oxidation in Mn(II) and Mn(II)/MnO2 systems was primarily occurred via electron-transfer with Mn(III) intermediate, however, Mn(III) species were rapidly oxidized into the less reactive oxidant Mn(IV). In the presence of DCP, As(III) oxidation was enhanced due to stabilization of Mn(III) species by complexation with DCP. Fe(II) enhanced the adsorption of Arsenic and DCP by MnO2, as Fe-(hydr)oxides formed, creating extra adsorption sites on MnO2. Three DCP byproducts were also identified by means of LC/MS analysis in the Mn(II)/MnO2-DCP system, with reaction As(III) oxidation pathways are proposed. The enhanced As(III) oxidation by Mn(II)/MnO2 system, in presence of DCP resulted due to a series of chemical reactions with hydroxyl and phenolic radicals generated in system, in addition to electron transfer with DCP-Mn(III) complexes. These results provide new insights into the environmental behavior of As(III) within mixed water systems containing metals (Mn/Fe) and phenolics.

Global Patterns of Constitutional Judicial Review Systems: Two Major Models of Constitutional Judicial Review in the World

Judicial constitutional review is an essential component of upholding constitutionalism, even though it is a relatively new concept outside the United States. The US Supreme Court set a precedent in 1803 in the Marbury v. Madison case by declaring legislative acts unconstitutional, which is widely regarded as the beginning of the principle or doctrine of judicial constitutional review. Since then, judicial constitutional review has become a widely accepted feature of most democratic legal systems. Comparative constitutional law recognizes two well-known models of judicial constitutional review: the American model of dispersed or decentralized review by ordinary courts and the constitutional Kelsen/European model of centralized review by a specialized constitutional court. Additionally, there are mixed or hybrid systems that combine elements of both models. Judicial constitutional review is an essential component of upholding constitutionalism, even though it is a relatively new concept outside the United States. The US Supreme Court set a precedent in 1803 in the Marbury v. Madison case by declaring legislative acts unconstitutional, which is widely regarded as the beginning of the principle or doctrine of judicial constitutional review. Since then, judicial constitutional review has become a widely accepted feature of most democratic legal systems. Comparative constitutional law recognizes two well-known models of judicial constitutional review: the American model of dispersed or decentralized review by ordinary courts and the constitutional Kelsen/European model of centralized review by a specialized constitutional court. Additionally, there are mixed or hybrid systems that combine elements of both models.

Novel technology for synergistic SO2 reduction during the carbonation process via a CaO-Char mixed system

A novel method to effectively achieve synergistic SO2 reduction during the carbonation process by the as-designed CaO-biochar system is developed. Coconut shells and calcined-limestone were used as biochar and calcium sources (denoted as CSC and LS), respectively. The introduced reductant creates the reduction condition making the Ca-based sulfation suppressed and the desulfurization prefers to undertake the reduction pathway during the simultaneous CO2/SO2 removal process. The competition of SO2 and CO2 for the calcium active sites is weakened, effectively alleviating the negative effect of SO2 presence on CO2 carbonation and generating valuable sulfur-product. With the mass ratio of LS and CSC is 3, the carbonation conversion of the LS-CSC(1:3) is 34% higher than that of the LS and the reduced-sulfur ratio of the system reaches about 85% indicating an effective CO2 capture synergistic SO2 reduction. The CO produced via the Boudouard reaction between CO2 and char is sufficient to play an important role in SO2 reduction, which effectively promotes the decarboxylation process in the reduction of SO2. It also facilitates the sulfur transfer from the reduced intermediate on the solid phase to the gas phase as a form of COS, promoting the reduction of SO2 through the Claus reaction.

The synergistic pyrolysis effects of polyethylene terephthalate with the additive of sewage sludge

Pyrolysis could be one of the promising ways for polyethylene terephthalate (PET) waste-based char production, while the adherence environmental persistent free radicals (EPFRs) brought the risks for the wide application. Co-pyrolysis was employed as the potential way to reduce the EPFRs and improve the char quality simultaneously with the introduction of sewage sludge (SS), and the optimization reaction conditions and the relative mechanisms were proposed in this work. EPFRs in PET-based char were found to decrease from 1.07 × 1018–4.84 × 1018 spins·g−1 to 2.17 × 1017–4.90 × 1017 spins·g−1, with 38.86–48.55% reduction at the mass ratio of 1:1 (PET:SS). The corresponding activation energy decreased by 78.83% with 30.93% higher biochar yield rate due to the synergistic effects. Co-pyrolysis facilitated the decomposition of benzoic acid and its derivatives by enhancing the cleavage of oxygen-containing functional groups and led to the binding of nitrogen with more pyrolysis intermediates, resulting in a reduction of precursors for oxygen/oxygenated-carbon centered radicals. More phenyl radicals were polymerized into carbon-centered radicals through hydride transfer and crosslinking in the mixed system. The additive of SS promoted the aromatization degree, enhanced the defect and pore structure of the biochar, and led to a 43.62-fold increase in the surface area of PET-based char at 400 °C. This work provides a potential approach to reduce EPFRs from the pyrolysis of plastic waste and to deal with multiple waste streams in venous industry park under the implementation of zero waste cities construction.

Experimental study on thermal stability and burn-back performance of aqueous film forming foam agent(AFFF) with short-chain fluorocarbon surfactant or flame retardant

Long-chain fluorocarbon surfactant is widely used in aqueous film-forming AFFF due to its excellent interfacial property. It can effectively improve the extinguishing efficiency of foam by improving the stability of foam. However, due to its severity environmental damage, some studies in recent years have focused on using short-chain fluorocarbon surfactants or flame retardants to replace long-chain fluorocarbon surfactants. However, the stability mechanism of foam after adding new additives and its performance in high-temperature thermal radiation environment are still unclear and require further clarification. Therefore, in this work, the effect of different additives on the interfacial properties of foam solution, foaming ability and foam stability, thermal stability and burn-back performance under the heat radiation environment are discussed. The results indicate that the thermal stability and burn-back performance of AFFF mixed with long-chain fluorocarbon surfactant (FS-30) or flame retardant (APP and MCA) was not significantly improved. However, the foam mixed with FS-50 exhibits excellent thermal stability and burn-back performance, it could be a proper substitute for long-chain fluorocarbon surfactants to be used in the AFFF mixed system. Through exploring the adsorption behavior of surfactant molecules on the liquid-air interface of the foam, FS-50 molecules and hydrocarbon surfactant molecules have a strong synergistic effect, which making it more difficult for water molecules to enter the surface of the mixed system. and the stability of foam will be enhanced. Besides, the proper mass concentration will also affect the interfacial properties of foam solution, foaming ability and foam stability, thermal stability and burn-back performance of the foam in fire environment, the mass concentration of additive in the foam solution should be remained at 0.3 wt%.

Adsorption of Hg2+/Cr6+ by metal-binding proteins heterologously expressed in Escherichia coli

BackgroundRemoval of heavy metals from water and soil is a pressing challenge in environmental engineering, and biosorption by microorganisms is considered as one of the most cost-effective methods. In this study, the metal-binding proteins MerR and ChrB derived from Cupriavidus metallidurans were separately expressed in Escherichia coli BL21 to construct adsorption strains. To improve the adsorption performance, surface display and codon optimization were carried out.ResultsIn this study, we constructed 24 adsorption engineering strains for Hg2+ and Cr6+, utilizing different strategies. Among these engineering strains, the M’-002 and B-008 had the strongest heavy metal ion absorption ability. The M’-002 used the flexible linker and INPN to display the merRopt at the surface of the E. coli BL21, whose maximal adsorption capacity reached 658.40 μmol/g cell dry weight under concentrations of 300 μM Hg2+. And the B-008 overexpressed the chrB in the intracellular, its maximal capacity was 46.84 μmol/g cell dry weight under concentrations 500 μM Cr6+. While in the case of mixed ions solution (including Pb2+, Cd2+, Cr6+ and Hg2+), the total amount of ions adsorbed by M’-002 and B-008 showed an increase of up to 1.14- and 4.09-folds, compared to the capacities in the single ion solution.ConclusionThe construction and optimization of heavy metal adsorption strains were carried out in this work. A comparison of the adsorption behavior between single bacteria and mixed bacteria systems was investigated in both a single ion and a mixed ion environment. The Hg2+ absorption capacity is reached the highest reported to date with the engineered strain M’-002, which displayed the merRopt at the surface of chassis cell, indicating the strain’s potential for its application in practical environments.

Effect of M/P ratio, w/c ratio, and additive contents on rheological properties of seawater mixed magnesium phosphate cement system

Rheological properties play a crucial role in determining the grouting effectiveness of magnesium phosphate cement (MPC) slurry. This study aims to investigate the effects of the magnesia-to-phosphate (M/P) ratio, water-to-cement (w/c) ratio, fly ash (FA), and metakaolin (MK) on the rheological properties of seawater-mixed MPC slurries using rheological tests and low-field 1H nuclear magnetic resonance (NMR). Two methods for incorporating FA were explored to modulate the rheological properties of the MPC. The results demonstrated time-dependent viscosity changes with two distinct phases, including a plateau and a subsequent period of sudden change, with the minimum apparent viscosity occurring as hydration progressed. The apparent MPC viscosity was influenced by the MgO-particle content and the theoretical water consumption, with M/P = 3 exhibiting the lowest apparent viscosity within a w/c range of 0.14–0.2. Moreover, the addition of FA increased the minimum apparent viscosity of the MPC slurry. During the pre-hydration stage, using FA as an MPC substitute yielded better rheological properties than using FA as an MgO substitute. The MK increased the apparent MPC viscosity considerably and adversely affected its rheology.

Effect of bacteria-algae ratio on treatment of anaerobic digested wastewater by symbiotic coupling of bacteria and algae under the background of carbon neutralization

Environmental pollution is a growing concern, particularly the impact of sewage treatment gas on the atmosphere's greenhouse effect. Efficient sewage resource recycling is crucial to achieving carbon neutrality. The bacteria-algae symbiotic sewage treatment system combines wastewater treatment, carbon dioxide fixation, and biomass energy recovery to achieve the goal of carbon neutrality, environmental protection, and the transformation of high-value added products. This paper presents the construction of a sequencing batch photobiological reaction system that utilizes a microbial-algae symbiotic relationship. The system was used to analyze the degradation effects of sCOD, TN, AN, and TP in anaerobic digestion wastewater by varying the microbial-algae ratios. Additionally, changes in the microbial community were analyzed to explore the system's potential for reducing carbon emissions. The study's findings indicate that: 1)When the ratio of bacteria to algae was 2:3, the removal rates of TN, AN, sCOD, and TP were 81.38%, 94.28%, 75.33%, and 96.56%. 2)Changing the ratio of bacteria to algae would affect the bacterial concentration in the mixed system, but not the bacterial community structure. The results indicate that a ratio of 2:3 enhances the removal of pollutants by bacteria and algae symbionts.3) Under the context of carbon neutralization, this paper investigates the reduction of carbon emissions in ADE treated by bacteria-algae symbiosis at the optimal bacteria to algae ratio. The experimental process can reduce 177.03 mg CO2 compared to complete nutrient consumption treatment, which is equivalent to a reduction of 355.08 g CO2 per 1 m3 of ADE. For full anaerobic treatment, this experimental process can reduce 228.35 mg of CO2 equivalent CH4, which translates to a reduction of 456.71 g of CO2 equivalent CH4 per 1 m3 of ADE.

Experimental and numerical study for assessment indoor air quality by adopting mixing ventilation with different occupants' density in Iraq hot climates

In this research, thermal of level comfort and air quality indoor were examined for different numbers of persons (occupants’ density) within a (3m × 2.5m × 2.5 m) office room. The office room is equipped with mixing ventilation system, temperature and air speed (17°C) and (2.5 m/s) respectively. The results of experimental experiments and results were compared with computational fluid-dynamics (CFD) analysis utilizing the turbulent (RNG, k-epsilon) model on a thermal manikin that represents a person’s body in a standing and sitting and position. The experimental study focused on measuring the velocity, air temperature, and carbon dioxide (CO2) concentration in different areas indoor the room, in addition to taking measurements around the heat manikins and in the breathing area. When analyzing numerical data, thermal of level comfort was assessed by air diffusion of performance Index (ADPI), predicted of percentage dissatisfied (PPD), and predicted of mean vote (PMV). The results indicate that thermal comfort and indoor air quality decline with more persons. Where the values of (ADPI), (PPD) and (PMV) change from (76.55 %), (6.325 %) and (0.021) to (64.25 %), (10.412 %) and (0.52) respectively, when the number of persons in the room increased from (two persons) to (four persons).

Synergistic Effect of Betaines and Dialkyl Chain Anionic Surfactants on Interfacial Arrangement: A Molecular Dynamics Simulation Study.

Mixed systems of betaines and anionic surfactants can have a significant synergistic effect and greatly reduce the interfacial tension (IFT), which has attracted an extensive amount of attention. However, this synergistic effect requires an anionic surfactant and betaine molecular size matching, which limits the scope of its application. In this work, we studied three mixed systems of sodium dialkyl sulfosuccinate (AOT) and betaines with different sizes by molecular dynamics simulation and an IFT experiment and explored the interfacial behavior and synergistic mechanism of AOT in single and mixed systems. The hydrophobic tail chain center angle, average rising height of carbon atoms, stretch degree and distance between the terminal carbon atoms of AOT, and tilt angles of betaine were calculated and analyzed in detail. Simulation results showed that the hydrophobic tail chain center angle of AOT in the single system was smaller, and it tended to extend into the oil phase. After being mixed with different betaines, AOT can adjust its size according to the interfacial vacancies of different betaine systems by changing the alkyl chain orientation and forming tighter interfacial films. The IFT experiment showed that betaine/AOT mixed systems achieved a lower IFT value compared with that of the single system, indicating that AOT showed a synergistic effect with betaines with different structures. This study will be importantly instructively significant for the design and research of betaine mixed systems in crude oil exploitation.

Design of PLC Electrical Control System

With the continuous expansion and development of factory enterprise scale, the development of automatic batching control system has also been accelerated. Batching mixing control system is a kind of raw materials mixed together according to a certain proportion, processing to produce a certain product process. This paper mainly designs and realizes the batching mixing control system of programmable logic controller (PLC). By precisely controlling the proportion of batching and the mixing time, the system is widely used in chemical, pharmaceutical, food and other fields to improve production efficiency and product quality. PLC system is a flexible, programmable electrical control equipment, because of its powerful, easy to use, high reliability characteristics, often used as the field data acquisition and equipment control. This paper mainly introduces the automatic control of liquid mixing system by Siemens PLC. The control object, hardware composition, software design and system function of the PLC based mixing, automatic mixing and automatic discharging system for two kinds of ingredients can simulate and display the whole working process of the liquid mixing system. The hardware of the system is mainly composed of S7-300 programmable controller, keys, stirring motor, frequency converter, solenoid valve and pump, etc. The programming software adopts Siemens programming software STEP7. The system transmits the collected field data to PLC through the weighing sensor, and after the PLC processes the field data logically, the corresponding control command is issued to complete the automatic control of the system. Finally, the system uses the communication interface to connect with the host computer to realize the communication between PLC and computer. The system has high degree of automation, strong flexibility, and can meet different production process requirements.

The effect of using nano and microbubbles as aeration strategies on the nitrification process, microbial community composition, and growth of Penaeus vannamei in a super-intensive biofloc system

The aim of this study was to evaluate the effect of using nano and microbubbles as aeration strategies on the nitrification process, microbial community composition of water and biofilm, microbial flocs proximate composition, and growth of Penaeus vannamei in a pilot scale super-intensive system with biofloc technology. A grow-out (stocking density: 450 shrimp m−3) was carried out for 74 days in a greenhouse with nine 35 m3 tanks, using the following treatments: T1: nanobubbles, T2: microbubbles, T3: mixed (nano + microbubbles). The nanobubbles were generated by nozzle-type air injectors and the microbubbles were generated by microperforated hoses. Artificial substrates, with an area equivalent to 200% of the lateral surface, were used into the experimental units. Molasses was used as an organic carbon source at a carbon:nitrogen ratio of 15:1. The main morphotypes of bacteria in the water and in the biofilm were analyzed using direct counting and a profile of the bacterial composition of the water was performed using metagenomic analysis. Control of total ammonia nitrogen (TAN) was better in treatments T2 and T3 than in T1. At the end of the experiment, treatment T3 showed a higher total abundance of bacteria in the water than T1 and T2. Bacillus abundance in the biofilm was higher in the T3 treatment than in T1 and T2. The relative abundance of nitrifying bacteria was <1% in all treatments. Treatment T1 had a higher relative abundance of nitrite-oxidizing bacteria than the others. However, the T3 treatment had a better distribution of nitrifying bacteria species. T3 treatment showed a higher diversity and evenness of operational taxonomic units. The microbial flocs in the T2 had a higher crude protein content than in the T1. These results indicate that the use of a mixed aeration system promotes a higher load of microorganisms, which has proven to improve water quality and can influence shrimp growth. The shrimp final weight was higher in T1 (12.57 g) and T3 (12.54 g) than in T2 (11.70 g), survival was higher in T3 (97.17%) than in T1 (80.33%), and yield was higher in T3 (4.61 Kg m−3) than in T1 (4.06 Kg m−3) and T2 (4.21 Kg m−3). The treatment that used nano and microbubble as aeration strategy (T3) proved to be the best as it provided better TAN control, higher abundance of bacillus bacteria in the biofilm, higher diversity and evenness of bacteria, and even higher shrimp growth and survival.

Therapists and patients perceptions of a mixed reality system designed to improve trunk control and upper extremity function

A prototype system aimed at improving arm function and trunk control after stroke has been developed that combines mixed-reality (MR) feedback with a mobile seat system (Holoreach). The purpose of this study was to assess the usability of Holoreach in a rehabilitation setting from both the patient and therapist perspective. Ten therapists (eight physiotherapists and two occupational therapists) used the device in their regular therapy programs for fifteen stroke patients with trunk control issues. Each patient received four individual therapy sessions with the device performed under the supervision of the therapist. Therapists and patients kept therapy diaries and used customized questionnaires. At the end of the study two focus groups were conducted to further assess usability. Generally, the prototype system is suitable for training trunk and arm control. The therapists expressed overall positive views on the impact of Holoreach. They characterized it as new, motivating, fresh, joyful, interesting, and exciting. All therapists and 80% of the patients agreed with the statement that training with Holoreach is beneficial for rehabilitation. Nonetheless, improvements are required in the hardware and software, and design. The prototype system contributes at various levels to the rapidly evolving advances in neurorehabilitation, particularly regarding the practical aspect of exercise delivery.

Citric acid-induced photochemical behavior of Cr(III)-substituted ferrihydrite: Fe and Cr release, mineral transformation and reactive oxygen species generation

Cr(III)-substituted ferrihydrite (Fh-Cr(III)) is widespread in the surrounding environment of mining areas. Fh-Cr(III) is unstable and susceptible to the influence of environmental factors, such as dissolved organic matter (DOM) and light, so Cr species embedded in mineral crystal layers are likely to have more profound negative effects on the environment with the photochemical behaviors of minerals. However, the photochemical behaviors of Fh-Cr(III) in the presence of DOM remains poorly understood. For this reason, citric acid (CA) was chosen as the representative DOM to study its combined effects with visible light irradiation on Fh-Cr(III) dissolution and phase transition. The results showed that CA hindered the agglomeration of Fh-Cr(III) particles, thereby slowing the phase transition of Fh-Cr(III). However, CA exacerbated the release of Fe and Cr by maintaining Fh-Cr(III) under unstable crystal structure. Moreover, due to the occurrence of ligand-metal charge transfer (LMCT) in (CA)n-Fh-Cr(III) formed on the Fh-Cr(III) surface, the synergistic effect between CA and light irradiation greatly promoted the dissolution of Fh-Cr(III). In the mixed system of Fh-Cr(III) (3 g/L) and CA (5 mM) at initial pH 3.0, the maximum concentrations of TFe and TCr were 18.17 and 5.68 mg/L after 6 h of light reaction, which were 1.82 and 3.62 times of those in the corresponding system in the darkness. Meanwhile, the Fe(III)/Fe(II) cycling in solution and solid surfaces was affected by various reactive oxygen species (ROS) generated from the LMCT process, in which the photoproduced Fe(II) further accelerated Cr(III) dissolution under acidic solution. The fast release of Cr(III) may pose greater danger to the environment as the more toxic Cr(VI) can be easily formed through the oxidation of dissolved Cr(III). This work offers fresh insights into the migration and transformation of Cr elements in the natural environment.

Environmental, social and economic sustainability in Lao coffee

Laos has experienced an emergence of coffee cultivation as Loa farmers, many of them women, have been cultivating coffee in the understorey of natural forests. This form of agroforestry produces high-quality specialty coffee, earning farmers a significant income while preserving biodiversity. Farmers’ adoption of agroforestry, in place of traditional shifting agriculture has been supported by initiatives like the Swiss Agency for Development and Cooperation (SDC) project, which establishes agroforestry learning centres and mini-processing centres, in collaboration with companies such as the MX Coffee Company and the Comma Coffee Company. Developments in coffee cultivation have been on the rise in the last three decades in Keoset, a community in Khoun District, where failed development projects were later revived by SDC and improved upon with market-oriented initiatives. The project has assisted in establishing coffee nurseries, providing training, and establishing partnerships with private companies for processing and marketing and as a result, farmers have advanced from selling unprocessed cherries to selling parchment (semi-processed beans), earning them a higher income. Farmers selling green beans are also collecting a premium price from roasting companies and exporters. The ability to generate an income from coffee cultivation is significant, because 90% of the farmers engaged in coffee cultivation are women, who are now able to depend on an independently earned income, granting them a greater voice in household decision-making. Climate change poses potential risk to the future of coffee production, but the protection offered by forests largely shields coffee crops from storms and changes in temperature. The forests' maintenance of biodiversity also protects the predators of pests and disease, ensuring no chemical methods are needed for pest control, including against the coffee cherry borer (Hypothenemus hampei). A variety of challenges remain for which there are recommended responses. Challenges of institutional and legal context require capacity building within the government; world price fluctuations necessitate that farmers practice a mixed farming system to not rely solely on coffee; geographical limitations promote a focus on specialty-grade coffee; and competition from other cash crops requires awareness of the environmental risks associated with other crops and stricter zoning and regulation over different production systems. It is worth heeding these recommendations, as agroforestry coffee systems enhance livelihoods, empower women, promote environmental sustainability and demonstrate resilience to climate change, making it a potential model for countries facing similar challenges in similar agroecological zones.

Shear bond and rebond strengths of four composite systems

which are chemically—cured composite such as Two—past and No—mix systems in whiclthe composite set by chemical reaction; Light—cured composite system, in whicl:composite set by light exposure; and Dual—cured composite system, by which thcomposite cured by chemical reaction and light exposure. Thus it is necessary tt.investigate and compare the commonly used composite bonding systemsThis study was aimed to determine and compare the shear bond and reboncstrength of: Two—past composite system (Concise, 3M, Unitek USA), No—mix composite,system (Right—On, TP Orthodontics UK), Light—cured composite system (Transbond XT.)M Unitek USA), and Dual—cured composite system (Sono—Cem ESPE, Germany3,Fifty six upper premolars were divided into four groups of fourteen, each groupmesh—backed metal advant edge brackets were bonded to the buccal surface ofthe teethusing one of the composite system according to the instruction of manufacturer. Then.bonded samples were thermocycled in an attempt to simulate oral circumstancesThe samples were subjected to shear force using the universal compressionmachine apparatus, then the results were recorded in Megapascal (Mpa). The remainingcomposite on the buccal surface of the tooth was removed by hand sealer and polished, anew bracket was bonded to the buccal surface of the tooth using the same type ofcomposite system. The rebonded samples were tested under shear strength using the.universal compression machine apparatus and the results were again recorded in Mpa,The data were statistically analyzed using descriptive analysis, ANOVA test.Dtu1can’s Multiple Range Test and Student’s t—test at p g 0.0lThe results showed that the Concise had no significant higher bond shear strengththan the Transbond and Sono—Cem composite systems, and there was signilicant increasebond strength of the Concise than the Right—On composite systems. Furthermore, therewere no significant differences in bond shear strength among the Right—On, Transbond.and Sono—Cem composite systems

Impacts of integration of mola with prawn–carp gher farming: An approach to enhance household fish consumption and family income

AbstractThis study investigated the production performance, household fish consumption, and commercial feasibility of prawn–carp–mola mixed gher farming system. Three treatments with different species compositions were compared: prawn + rohu, prawn + mola, and prawn + rohu + mola, each having different stocking densities. The results indicated that the integration of mola improved the utilization of feed protein by prawns. However, mola inclusion did not significantly affect the growth of prawn and rohu or the production system's cost. Mola inclusion led to a significant increase in the gross production, household consumption, and sale of mola, prawn, and rohu. It also increased gross returns, income above variable cost, and net returns to land, family labor, and management. In addition, the inclusion of mola significantly increased household consumption by increasing the intake of nutrient‐rich mola and overall fish consumption. This improvement in food consumption contributed to ensuring the nutritional requirements and food security of impoverished rural farmers, especially women and children. Consequently, the integration of small fish mola in prawn–carp gher farming systems is recommended as a beneficial practice for wider adoption, effectively addressing household nutrition security at the rural level and improving the livelihoods of farmers.

Assessment of water purification by IRMOF-1 based on rGO as a new nanoengineered adsorbent: Insights from adsorption mechanism

The main challenge in the use of synthetic dyes and microplastics is their release into water resources, which has adverse effects on human health and the ecosystem. Hence, adsorption removal has been considered an efficient treatment method for pollution remediation from wastewater and industrial effluents. Metal-organic framework/graphene oxide composites can be effectively used for wastewater treatment. In the present study, the uptake mechanism of the cationic dyes, Methylene Blue (MB) and Rhodamine B (RhB), as well as Polyurethane (PU) microplastic by IRMOF-1 based on reduced graphene oxide (IRMOF-1/rGO) nanocomposite was comprehensively evaluated using molecular dynamics (MD) simulation. The contaminant molecules can be adsorbed on the designed nanocomposite to some extent, and which adsorbent exhibits an obvious preference for removing MB over RhB/PU and selectivity. In the case of cationic dyes, the accumulation of textile molecules is observed near the surface of reduced graphene oxide, whereas the metal-organic framework component illustrates a significant uptake capacity for PU microplastic. The tendency of PU microplastics to form a self-organized pattern is noticed in the PU@IRMOF-1/rGO system, but this tendency is less with the coexistence of MB in the mixed system. Increasing the dispersion of microplastic in the mixed system leads to an enhancement in the solvent-accessible surface area of PU from 40.60 nm2 in the individual system to 46.50 nm2 in the mixed system, respectively. It is found that the π-π conjugation, pore-filling effect, van der Waals, and electrostatic interactions govern the water purification mechanism by designed nanocomposite. This work gives a more detailed insight into the use of IRMOF-1@rGO nanocomposite as an effective technology for the decontamination of toxic dyes and microplastics from wastewater.

Multifunctional asymmetric bi-ligand iron chelating agents towards low-cost, high performance, and stable zinc-iron redox flow battery

Zinc‑iron flow batteries hold great potential as stationary storage due to their attractive cost and abundance of materials; however, they still suffer from precipitation problems. This work demonstrates a novel asymmetric iron complex with bi-ligand from pyridine and disodium 4,5-dihydroxy-1,3-benzenedisulfonate (TIRON) to synergically reduces precipitation, improves the mass transport of the redox-active species, and lowers the electron transfer resistance. The low activation barrier of mixed complexes calculated via the Density Functional Theory (DFT) explains the ease of redox reaction, which is reflected in the low overpotential voltage in the Fe//Fe symmetrical cell. Moreover, no change in Raman and Fourier-transform infrared spectroscopy peaks after symmetrical cell cycling confirms the stability of the mixed complexes catholyte. Contrary to other works, our strategy requires a lower molar ratio of complexes per iron, while still yields a superior capacity of 6.81 Ah/L. From its outstanding capacity utilization, the overall cost of the electrolytes for the mixed complexes system is only $26.3/kWh, which is lower than the non-complex iron system at $42.9/kWh. Additionally, the mixed complexes battery can be operated stably for >200 cycles. Our perspective on eco-friendly and low-cost catholyte design accelerates development towards reliable stationary storage with high performance and stability.

Adsorption Capacity of Carbon-Silica Composites Towards Diclofenac in Poly(acrylic acid) Containing Systems: A Crucial Study on Common Wastewater Contaminants.

Diclofenac is one of the most popular over-the-counter non-steroidal anti-inflammatory drug and poly(acrylic acid) is a frequently used as thickener, filler or stabilizer. For these reasons, they are common organic contaminants in raw wastewater. The purpose of the presented studies was to compare the adsorption capacity of three carbon-silica composites - metal-free C/SiO2 , iron-enriched C/Fe/SiO2 and manganese-enriched C/Mn/SiO2 towards diclofenac. The studies were carried out in single, and mixed systems in the presence of poly(acrylic acid) polymer. Adsorption, desorption and kinetics of the adsorption process were investigated. The concentration of diclofenac in the supernatants was determined using high-performance liquid chromatography. The solids were also characterized with an ASAP apparatus using low-temperature nitrogen desorption adsorption isotherms at liquid nitrogen temperature. In addition, potentiometric titrations and electrophoretic mobility measurements, as well as stability tests of the studied suspensions were carried out. The most efficient composite among investigated ones proved to be C/Fe/SiO2 removing diclofenac at the level of 46.68 mg/g for its initial concentration of 90 ppm. The results obtained clearly demonstrated that the carbon-silica composites are effective in separation of drugs from aqueous solutions and can be successfully used in the future for the removal of organic pollutants from water environment.