Hard Ions Research Articles

Slow Magnetic Relaxation in a Dysprosium Metallocene Complex Bearing Equatorial DyIII−P Bonds

AbstractSingle molecule magnets (SMMs) containing dysprosium‐phosphorus bonding are rare due to great challenges in constructing the bonding between hard lanthanide ions and soft phosphorus donors. Here we successfully isolated a novel mononuclear bis‐Cp* dysprosium compound, Cp*2Dy[η‐CH(PPh2)2]⋅C7H8 (1‐Dy), via the salt metathesis reactions of Cp*2Dy(BPh4) and K[(PPh2)2CH] in THF (Cp*=pentamethylcyclopentadienyl). The magnetic investigations indicate its strong SMM behavior evidenced by the open magnetic hysteresis loops below 6 K and the high effective barrier of 300 cm−1. This could be ascribed to weak dative DyIII−P bonds at equatorial sites in such [Cp2DyX]‐type (X=auxiliary donors) complexes.

A new strategy toward synthesis of novel bifunctional N- and S-bearing sorbent for platinum(IV) removal from aqueous solutions and acidic leaching residue of Pt/Al2O3 catalyst

Strong incentive politics have been elaborated for promoting the recovery of precious metals from secondary resources. Solid leaching generates acidic effluents that can be pre-treated using precipitation steps for partial separation before applying sorption for metal recovery from mild acidic solutions. For this purpose, a new sorbent was designed bearing numerous N- and S-bearing reactive groups with good affinity for platinum (as chloroanionic species). Thiazole precursors were first reacted before being grafted (by free radical reaction) with triallyl cyanurate (to form CTTR sorbent). The material was characterized by a series of analytical tools (SEM, BET, FTIR, XPS, TGA, elemental analysis, and titration). The effect of pH combined with FTIR and XPS spectroscopy analyses allowed identifying the mechanisms involved in metal binding: (a) electrostatic attraction of chloroplatinate anions with protonated amine groups (especially in acidic conditions), (b) while at moderate acidic pH metal sorption proceeds through ligand exchange and chelation onto N-based and S-based groups. Optimum sorption was found at pH close to 4 (near pHpzc value). Under selected experimental conditions, the equilibrium was reached in 25–35 min. The pseudo-first order rate equation fitted well experimental profile (though the resistance to intraparticle diffusion contributes to the kinetic control). The maximum sorption capacity at room temperature reached up to 1.58 mmol Pt g−1 (at pH 4). The sorption isotherm was successfully fitted by the Temkin equation. The sorption is spontaneous and exothermic (with reduction in maximum sorption capacity reaching up to 25 %, when temperature increases to 50 °C). Optimum platinum desorption was obtained with 0.3 M HCl solution (with solid/liquid ratio 1.67 g L−1) for complete desorption and enrichment factor close to 4.6. Complete desorption was maintained over 5 cycles, while the sorption efficiency decreased by less than 3.5 % at the fifth cycle. The sorbent showed remarkable stability for PGMs (Pd(II) in addition to Pt(IV)) against alkali-earth elements or base metals (from equimolar synthetic solutions); the selectivity is driven by the preference of the reactive groups (soft base and intermediary base) for soft PGM metals against hard and borderline metal ions; this selectivity is also affected by metal speciation (formation of chloro-anionic species). The valorization of platinum from non-compliant Pt/Al2O3 catalyst was investigated after leaching with aqua regia. Platinum was precipitated from the leachate with ammonium chloride. In a second step, aluminum was removed by precipitation at pH 5. The residual solution was then treated by adsorption on CTTR: optimum separation between Pt and Al was achieved at pH ≈ 3.

Utilization of Schiff base ligands to chelate Ag+ for highly specific and sensitive Hg2+/Ag+ immunoassay

In this study, a planar benzothiazole Schiff base derivative ZX1 was designed and synthesized to selectively precipitate silver ions, in conjunction with the immunoassay detection of Hg2+ ions. The silver chelation process was highly effective in the pH range of 7–10, with a silver ion precipitation ratio of 99.9 %. The coordination behavior of ZX1 with Ag+ was studied using a series of spectroscopic measurements, topography analysis and DFT calculation. The shortest bond distances were 2.251 and 2.254 Å between nitrogen atom of thiazole and Ag+. Weak interactions were analyzed using the interaction region indicator (IRI) method and VMD. The immunoassay was developed through an anti-Hg2+/Ag+ monoclonal antibody, which showed similar sensitivities for Ag+ and Hg2+. The selectivity and anti-interference ability of the Schiff base ligands were tested for some hard metal ions and several anions. With co-existence of interference ion Ag+, Hg2+ was detected in rice matrix solution with 77 %∼123.5 % recovery by addition of ZX1 as the masking reagent and 90.3 %∼115 % for wheat matrix. This research provides a promising immunoassay strategy for simultaneous detection of silver ions and mercury ions in food matrix by utilization of Schiff base ligands. This novel Schiff base ligand was then used as the pre-treatment reagent to remove silver ions within 5 min for detection of Hg2+ or detection of both Ag+ and Hg2+ based on a novel bi-specific heavy metal antibody.

Optimizing the Structure of a Pt Metal-Chelating Polymer to Reduce Nonspecific Binding for Mass Cytometry.

Mass cytometry is a bioanalytic tool based on atomic mass spectrometry for detecting biomarker expression on individual cells. Current reagents employ metal-chelating polymers binding isotopes of hard metal ions. Polymers bearing chelators for soft metal ions offer the promise for a large increase in multiplexing capabilities, but examples reported so far often have unacceptably high levels of nonspecific binding (NSB). We recently reported a new class of metal-chelating polymers with dipicolylamine (DPA) chelators that could bind Re and Pt. They also showed significant levels of NSB. Here, to reduce the NSB of the Pt-DPA polymer, we grafted water-soluble oligomers to the distal end of the dipicolylamine pendant group. Methoxy(polyethylene glycol) (DP = 24) was effective as was poly(sulfobetaine methacrylate) (DP = 29). Reacting the Pt-Cl bond of the metalated polymer with glutathione was remarkably effective at suppressing NSB. These results open the door to Pt-isotope-based metal-chelating polymers as new mass tags for mass cytometry.

In situ evolution of electrocatalysts for enhanced electrochemical nitrate reduction under realistic conditions

Electrochemical nitrate reduction to ammonia (ENRA) is gaining attention for its potential in water remediation and sustainable ammonia production, offering a greener alternative to the energy-intensive Haber-Bosch process. Current research on ENRA is dedicated to enhancing ammonia selectively and productivity with sophisticated catalysts. However, the performance of ENRA and the change of catalytic activity in more complicated solutions (i.e., nitrate-polluted groundwater) are poorly understood. Here we first explored the influence of Ca2+ and bicarbonate on ENRA using commercial cathodes. We found that the catalytic activity of used Ni or Cu foam cathodes significantly outperforms their pristine ones due to the in situ evolution of new catalytic species on used cathodes during ENRA. In contrast, the nitrate conversion performance with nonactive Ti or Sn cathode is less affected by Ca2+ or bicarbonate because of their original poor activity. In addition, the coexistence of Ca2+ and bicarbonate inhibits nitrate conversion by forming scales (CaCO3) on the in situ-formed active sites. Likewise, ENRA is prone to fast performance deterioration in treating actual groundwater over continuous flow operation due to the presence of hardness ions and possible organic substances that quickly block the active sites toward nitrate reduction. Our work suggests that more work is required to ensure the long-term stability of ENRA in treating natural nitrate-polluted water bodies and to leverage the environmental relevance of ENRA in more realistic conditions.

Three-dimensional alkaline earth metal-organic framework poly[[μ-aqua-aqua-bis-(μ3-carba-moyl-cyano-nitro-somethanido)barium] monohydrate] and its thermal decomposition.

In the structure of the title salt, {[Ba(μ3-C3H2N3O2)2(μ-H2O)(H2O)]·H2O} n , the barium ion and all three oxygen atoms of the water mol-ecules reside on a mirror plane. The hydrogen atoms of the bridging water and the solvate water mol-ecules are arranged across a mirror plane whereas all atoms of the monodentate aqua ligand are situated on this mirror plane. The distorted ninefold coord-ination of the Ba ions is completed with four nitroso-, two carbonyl- and three aqua-O atoms at the distances of 2.763 (3)-2.961 (4) Å and it is best described as tricapped trigonal prism. The three-dimensional framework structure is formed by face-sharing of the trigonal prisms, via μ-nitroso- and μ-aqua-O atoms, and also by the bridging coordination of the anions via carbonyl-O atoms occupying two out of the three cap positions. The solvate water mol-ecules populate the crystal channels and facilitate a set of four directional hydrogen bonds. The principal Ba-carbamoyl-cyano-nitro-somethanido linkage reveals a rare example of the inherently polar binodal six- and three-coordinated bipartite topology (three-letter notation sit). It suggests that small resonance-stabilized cyano-nitroso anions can be utilized as bridging ligands for the supra-molecular synthesis of MOF solids. Such an outcome may be anti-cipated for a broader range of hard Lewis acidic alkaline earth metal ions, which perfectly match the coordination preferences of highly nucleophilic nitroso-O atoms. Thermal analysis reveals two-stage dehydration of the title compound (383 and 473 K) followed by decomposition with release of CO2, HCN and H2O at 558 K.

Deciphering geochemical fingerprints and health implications of groundwater fluoride contamination in mica mining regions using machine learning tactics.

The contribution of mica mining activities to fluoride (F-) contamination in groundwater has been chased in this study. For the purpose, groundwater samples (n = 40, replicated thrice) were collected during the post-monsoons (September-October) from a mica mining area in the Tisri block of Giridih district, Jharkhand. The study has employed a synergy of classical aquifer chemistry, statistical approaches, different indices, Self-Organising Maps (SOM), and Sobol sensitivity index (SSI) to unveil the underlying aquifer chemistry, identify the impacts of mining activities on groundwater quality and its associated health hazard. Fluoride levels varied from 0.34 to 2.8ppm, with 40% of samples exceeding the World Health Organization's permissible limit (1.5ppm). Physicochemical analysis revealed significant differences in electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH) and major ion concentrations (Na+, HCO3-, Ca2+) between fluoride-contaminated (FC) and fluoride-uncontaminated (FU) groups. Higher Na+ and HCO3- associated with F- contaminated samples, were indicative of silicate weathering and carbonate dissolution as primary geogenic sources for this ion. Health risk assessment (HRA) revealed hazard quotient (HQ) values exceeding unity, indicating non-carcinogenic risks, particularly for children in most samples from group FC. The mean Water Quality Index (WQI) of FC group (156.76 ± 7.30) was significantly higher (p < 0.05) than group FU indicating of its unsuitability. SOM could accurately (80%) predict presence of fluoride in water samples based on other major ions. Sobol sensitivity analysis successfully identified fluoride concentration and body weight as most impactful parameters affecting human health. The integration of advanced modelling techniques and geospatial analysis as Inverse Distance Weightage (IDW) maps has provided a robust framework for ongoing groundwater quality monitoring in mining-affected regions and can help proactive intervention in risk-prone areas. Overall, this comprehensive study takes us a step ahead towards ensuring safe drinking water access for the global community.

Hydrogeochemistry and human health risk assessment of heavy metal pollution of groundwater in Tarkwa, a mining community in Ghana

The current study investigated the geochemical characterization and contamination of groundwater quality in Tarkwa, a mining community in Ghana. Total dissolved solids, electrical conductivity, calcium, magnesium, sodium, potassium, total dissolved solids, total hardness, heavy metals, and cyanide (CN) were all assessed in 74 groundwater samples. Other parameters assessed included pH, electrical conductivity, carbonate, bicarbonate, chloride, sulphate, nitrate, and pH. Using the method recommended by the USEPA, a health risk assessment was carried out. Among the parameters which exceeded their WHO recommended threshold were pH (4.9–7.7), Conductivity (150–1082 µS/Cm), Turbidity (1.4–139.5 NTU), Magnesium (1.9–395.5 mg/L), Nitrate (4.5 mg/L–760 mg/L), phosphate (2.3–80 mg/L), Sulphate (10–855.6 mg/L), CN (1.6–16 mg/L), As (0.001–0.015 mg/L), Hg (0.001–0.005 mg/L), Cd (ND-0.009 mg/L), Mn (0.004–1.38 mg/L), Ni (0.002–0.118 mg/L). The study also showed that the groundwater in Tarkwa is naturally hard, making Ca and Mg ions the main ions determining the chemistry of the water. Similar to this, the most significant factors affecting water chemistry were rock dominance and precipitation dominance. Due to high levels of CN, As, and Cd, health risk evaluation revealed that prolonged intake of groundwater from Tarkwa is linked to both carcinogenic and noncarcinogenic health risk. Children were shown to be more vulnerable to both carcinogenic and noncarcinogenic health risks than adults.

An experimental study on the parthenium biosorbents for removals of chlorides and hardness from contaminated water

Among the problems most severe for the environment is the pollution of aqueous solution, specifically the creation of threats connected to hazardous heavy metals. In some rural places, it is hardness and chlorides that make groundwater or surface water dangerous in terms of the level of toxins. The requirement of hardness and chlorides is influenced because, in large quantities, when it comes to the quality of drinking water, it causes disease. Water is hazardous to the eyes because of its alkaline nature, inhalation organs, and skin problems. The more hardness and chlorides and related irritations there are, the larger the share. A naturally occurring physiochemical mechanism called biosorption enables certain biomass to passively adsorb hardness and chlorides into the biomass's cellular structure. In the lab, five distinct biosorbents were created, including parthenium, rice husk, rapeseed straw, sawdust, and egg cells, in that order. The parthenium biosorbents turned out to be the most successful biosorbents, despite the fact that each biosorbents has a different level of effectiveness in eliminating hardness and chlorides from water. By using the plant based biomass of parthenium, 65 % of chloride removal with 80 % of hardness removal was obtained. Having identified the best biosorbents, we optimized their parameters and took water samples from different sources. In chlorides removal over parthenium biosorbents, the optima dosage of biosorbents is 3.8 g, temperature is 35 °C, pH is 7, contact time is 120 min and optima agitation speed is 120 rpm. In hardness removal over parthenium biosorbents, the optima dosage of biosorbent is 5.4 g, temperature is 35 °C, pH is 6.5, contact time is 90 min and agitation speed is 150 rpm. Once the chlorides and hardness ions are removed from the water by the utilized biosorbents, the biosorption process may be homo cost effective through the regeneration and reuse of the biosorbent.

Adsorption studies on synthetic lentil-like mordenite for column and batch removal of cadmium and lead ions: investigating isotherms and kinetics

ABSTRACT The mordenite zeolite adsorbent, with a lentil-like structure, was synthesised using a one-step green hydrothermal method. Its textural, structural, and morphological properties were characterised through X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, and the Brunauer-Emmet-Teller (BET) method. The prepared adsorbent was employed in both continuous and batch adsorption processes to remove toxic Cd(II) and Pb(II) metal ions from aqueous solutions. Operational parameters such as flow rate, initial concentration, and bed height were varied to understand breakthrough time, mass transfer zone, adsorption capacity, and exhaustion time during continuous adsorption, which were investigated and optimised. Additionally, the study explored the influence of solid/liquid ratio, pH, assay time, and initial concentration on batch adsorption. The maximum adsorption capacities of the lentil-like mordenite zeolite in fixed-bed breakthrough experiments were determined to be 78.22 mg/g for Cd (II) ions and 80.82 mg/g for Pb (II) ions. In batch experiments, the capacities were 133.64 mg/g for Cd (II) ions and 239.57 mg/g for Pb (II) ions. Dynamic continuous adsorption isotherms exhibited an excellent fit with the Thomas and Yoon – Nelson models, while batch adsorption isotherms conformed well to the Langmuir model. This study presents a new approach for synthesising high surface area, engineered morphology, reusable, and stable zeolite for effectively adsorbing hard metal ions from wastewaters, contributing to environmental remediation.

Membrane capacitive deionization (MCDI): A flexible and tunable technology for customized water softening

There is a growing demand for water treatment systems for which the quality of feedwater in and product water out are not necessarily fixed with “tunable” technologies essential in many instances to satisfy the unique requirements of particular end-users. For example, in household applications, the optimal water hardness differs for particular end uses of the supplied product (such as water for potable purposes, water for hydration, or water for coffee or tea brewing) with the inclusion of specific minerals enhancing the suitability of the product in each case. However, conventional softening technologies are not dynamically flexible or tunable and, typically, simply remove all hardness ions from the feedwater. Membrane capacitive deionization (MCDI) can potentially fill this gap with its process flexibility and tunability achieved by fine tuning different operational parameters. In this article, we demonstrate that constant-current MCDI can be operated flexibly by increasing or decreasing the current and flow rate simultaneously to achieve the same desalination performance but different productivity whilst maintaining high water recovery. This characteristic can be used to operate MCDI in an energy-efficient manner to produce treated water more slowly at times of normal demand but more rapidly at times of peak demand. We also highlight the “tunability” of MCDI enabling the control of effluent hardness over different desired ranges by correlating the rates of hardness and conductivity removal using a power function model. Using this model, it is possible to either i) soften water to the same hardness level regardless of the fluctuation in hardness of feed waters, or ii) precisely control the effluent hardness at different levels to avoid excessive or insufficient hardness removal.

Investigating the Effect of Water Softening on Polymer Adsorption onto Carbonates through Single-Phase and Two-Phase Experiments

Summary Polymer retention is considered a major challenge in polymer flooding applications, especially in carbonates. This is due to the prevailing conditions of low permeability (&amp;lt;100 md), high temperature (&amp;gt;85°C), and high salinity (&amp;gt;100,000 ppm) generally found in these formations, which limit the effectiveness of commonly used polymers such as hydrolyzed polyacrylamide (HPAM) and xanthan gum. To address these challenges, a polymer based on acrylamide tertiary butyl sulfonate (ATBS) has been used due to its tolerance to high-temperature and -salinity conditions. However, the high cost of manufacturing these polymers, combined with their anionic properties that promote adsorption onto positively charged carbonate rocks, necessitates the exploration of methods to reduce polymer retention. In this study, we aim to determine the sufficient concentration of hardness ions (Ca2+ and Mg2+) required to significantly reduce the adsorption of this polymer. The study is unique in its focus on mitigating polymer retention in carbonate formations using softened brine, as no prior research has investigated this aspect. Four different brines were investigated with a salinity of 8,000 ppm total dissolved salts (TDS) and varying ionic composition designed mainly by eliminating the hardness-causing ions, Ca2+ and Mg2+. A geochemical study was performed using the PHREEQC software to analyze the interaction between these injected brines and the rock. Furthermore, comprehensive rheological and static adsorption studies were performed at a temperature of 25°C using the potential ATBS-based polymer to evaluate the polymer performance and adsorption in these brines. Later, dynamic adsorption studies were conducted in both single-phase and two-phase conditions to further quantify polymer adsorption. The geochemical study showed an anhydrite saturation index (SI) of less than 0.5 for all the brines used when interacting with the rock, indicating a very low tendency for calcium sulfate precipitation. Furthermore, the rheological studies showed that polymer viscosity significantly increased with reduced hardness, where a polymer solution viscosity of 7.5 cp was obtained in zero hardness brine, nearly 1.5 times higher than the polymer viscosity of the base makeup brine of 8,000 ppm. Moreover, it was observed that, by carefully tuning the concentrations of the divalent cations, the polymer concentration consumption for the required target viscosity was reduced by 40–50%. For the single-phase static adsorption experiments, the polymer solution in softened brines resulted in lower adsorption in the range of 37–62 µg/g-rock as opposed to 102 µg/g-rock for the base makeup brine. On the other hand, the single-phase dynamic adsorption results showed an even lowered polymer adsorption of 33 µg/g-rock for the softened brine compared with 45 µg/g-rock for the base makeup brine. Additionally, the single-phase dynamic adsorption studies showed a remarkable improvement in polymer injectivity using softened brine. The polymer retention in wettability-altered cores was further reduced. The study highlights that water softening improves the performance of polymers, specifically in terms of lowering polymer adsorption. It concludes that a threshold hardness level (Ca2+ and Mg2+) of approximately 100 ppm is sufficient to achieve a significant reduction in polymer adsorption for the tested experimental conditions. In this paper, we show that the softened water increases the polymer viscosity and reduces polymer adsorption, which leads to an overall reduction in polymer consumption. Hence, the softened makeup water has the potential to enhance the application envelope of this potential polymer for polymer flood, especially in the case of carbonate reservoirs.

Low-maintenance anti-scaling of nanofiltration pretreated by bipolar-induced electrolysis for decentralized water supply

Nanofiltration (NF) offers an effective solution to ensure a decentralized water supply. However, its reliance on dosing for pre-precipitation and anti-scaling severely complicates its maintenance, adding to its cost and limiting its application, especially in rural areas. In this study, a bipolar-induced electrolysis (BIE) pretreatment method was developed to reduce the NF membrane scaling potential without the need for additional reagents. The water flux of the BIE-NF increased by 24.2 ± 6.5 % compared to traditional NF. This benefits from the synergistic effects of electrocoagulation (EC) and electro-precipitation (EP) of BIE to remove hardness ions (36.8 ± 0.7 g CaCO3 m−2 h−1), 26.2 ± 2.6 % and 16.1 ± 4.7 % faster than that of traditional EP and EC, respectively, exhibiting robust resistance to the interfering ions and organics. The unit energy consumption of BIE was only 18.9 ± 1.0 kWh/(kg CaCO3), 11.8 ± 1.9 % and 67.0 ± 1.4 % lower than that of EP and EC, respectively. After BIE electrolysis, the Ca, humic acid, and Mg contents were dramatically reduced, and a uniformly loose fouling layer formed on the NF membrane, demonstrating alleviated membrane scaling. Remarkably, BIE softening demonstrated its stability and feasibility in sustaining 120.0 m3/d of drinking water to rural populations without requiring additional reagents or manual maintenance, minimizing the operation and maintenance cost to 5.1 US cents/m3 water, 29.0 % lower than the cost of conventional dosing pretreatment. This study offers a low-cost and sustainable method for water supply through decentralized membrane purification.

Bimetal-Organic Frameworks Incorporating Both Hard and Soft Base Active Sites for Heavy Metal Ion Capture.

The design and synthesis of stable porous materials capable of removing both hard and soft metal ions pose a significant challenge. In this study, a novel metal-organic framework (MOF) adsorbent named CdK-m-COTTTB was developed. This MOF material was constructed using sulfur-rich m-cyclooctatetrathiophene-tetrabenzoate (m-H4COTTTB) as the organic ligand and oxygen-rich bimetallic clusters as the inorganic nodes. The incorporation of both soft and hard base units within the MOF structure enables effective removal of various heavy metal ions, including both soft and hard acid species. In single-component experiments, the adsorption capacity of CdK-m-COTTTB for Pb2+, Tb3+, and Zr4+ ions reached levels of 636.94, 432.90, and 357.14 mg·g-1, respectively, which is comparable to specific MOF absorbents. The rapid adsorption process was found to be chemisorption. Furthermore, CdK-m-COTTTB exhibited the capability to remove at least 12 different metal ions in both separate and multicomponent solutions. The material demonstrated excellent acid-base stability and renewability, which are advantageous for practical applications. CdK-m-COTTTB represents the first reported pristine MOF material for the removal of both hard and soft acid metal ions. This work serves as inspiration for the design and synthesis of porous crystalline materials that can efficiently remove diverse heavy metal pollutants.

A novel membrane-free electrochemical separation-filtering crystallization coupling process for treating circulating cooling water

The traditional electrochemical descaling process exhibits drawbacks, including low OH− utilization efficiency, constrained cathode deposition area, and protracted homogeneous precipitation time. Consequently, this study introduces a novel membrane-free electrochemical separation-filtering crystallization (MFES-FC) coupling process to treat circulating cooling water (CCW). In the membrane-free electrochemical separation (MFES) system, OH− is rapidly extracted by pump suction from the porous cathode boundary layer solution, preventing neutralization with H+, thereby enhancing the removal of Ca2+ and Mg2+. Experimental results indicate that the pH of the pump suction water can swiftly increase from 8.13 to 11.42 within 10 min. Owing to the high supersaturation of the pump suction water, this study couples the MFES with a filtration crystallization (FC) system that employs activated carbon as the medium. This approach captures scale particles to enhance water quality and expedites the homogeneous precipitation of hardness ions, shortening the treatment time while further augmenting the removal rate. After the MFES-FC treatment, the single-pass removal rates for total hardness, Ca2+ hardness, Mg2+ hardness, and alkalinity in the effluent reached 92 %, 97 %, 64 %, and 67 %, respectively, with turbidity of 3 NTU, current efficiency of 86.6 %, and energy consumption of 7.19 kWh·kg−1 CaCO3. This coupling process facilitates an effective removal of hardness and alkalinity at a comparatively low cost, offering a new reference and inspiration for advancements in electrochemical descaling technology.

تقييم جودة المياه في سد سماقولي للشرب والري و تربية الاسماك

لقد أجريت هذه الدراسة لمعرقة نوعية المياه وملائمته لمختلف الاغراض كالشرب والري وتربية السمك في سد سماقولي وذلك بالاعتماد على مقياس نوعية وجودة المياه (WQI) بدلالة رقم مقياسى لاى استخدام مطلوب ، جمعت عينات المياه من ثمانية مواقع خلال فتره امتدت من شهر ايلول 2021 لغاية تموز 2022، حيث تم تحديد معيار جودة او نوعية المياه (WQI) لأغراض الشرب ، وذلك بالاعتماد على أهم خمسە عشر معيارًا فيزيائيًا وكيميائيًا بما في ذلك: الأس الهيدروجين(PH)،التوصيل الكهربائي EC))، التعكرTurbidity)) ، الأكسجين المذاب DO))، الأكسجين الكيميائي الحيوي المطلوب ، القاعدية الكلية TA))، العسرة الكلية TH))، أيونات الكالسيوم والمغنيسيوم Ca &amp; Mg ions))، الصوديومNa) )، البوتاسيوم K))، الكلوريد Cl))، النتريتNO2) )، النترات NO3)) والكبريتاتSO4) ). كما إعطيت الوزن النسبي لكل متغيراو معيار تراوحت من 1 إلى 5 بناءً على أهم متغيراو معيار ضروري واساسى للحياة المائية والاستخدام اليومى و المنزلي. أشارت النتائج الدراسة إلى أن مياه سد سماقولي بمدخله ومخرجه صالحة للشرب بعد اجراء المعالجة التقليدية، اذ تراوحت نتائج (DWQI) لجميع المواقع بين ( 68.11إلى 83.93)، اما بالنسبة لمؤشر جودة او نوعية مياه الري (IWQI)، تم تحليل العينات المدروسة لمحتويات EC ونسبة امتصاص الصوديوم (SAR) والصوديوم (Na + 1) والكلوريد (Cl-1) وبيكربونات(HCO3).كما تراوحت نتائج (IWQI) من (68.84 إلى 70.20)، وهذا يدل الى أن عينات المياه تقع ضمن فئة الحصر المنخفض (LR) والمتوسط (MR) لأغراض الري. واخيرا سبع معايير استعملت شملت: الأس الهيدروجيني(PH)، التعكر (Turbidity) ، المواد الصلبة الذائبة (TDS)، الأكسجين المذاب (DO) ، القاعدية الكليةTH) ) والنتراتNO3) ). لتقييم نوعية وملائمة مياه سد سماقولى لتربية الاسماك بالاعتماد على محدودية المعيارى لكل وحدة من تلك المعاييرز أشارت النتائج لتلك المعايير فى جميع المواقع إلى أن المياه ملائمة ضمن محدودية المعايير لتربية الاسماك باستثناء معيارالعسرة الكلية TH..

Behavioral and Biochemical Variations in Unio tigridis After Exposure to Lead Nitrate

This study was carried out with the freshwater mussel Unio tigridis exposed to lead nitrate. The samples of water and mussels were collected from Qandil water resources situated in Qandil village at 36° 37' 39.55" north latitude and 44° 10' 51.80" east longitude, and it is 322 meters above sea level. In January 2022, rivers and aquariums water were tested for temperature, pH, EC, TDS, DO, total alkalinity, total hardness, and calcium and magnesium ions. Studied organisms were exposed to variable concentrations of lead nitrate ranging from 0 to 900 ppm. The 96-h median lethal concentration (LC50) was measured and a comparison was made between the behavioural responses of the control and treatment groups. Also, the concentrations of lead in the experimental media, shell, and soft tissue of mussels were measured. A sample of mussels collected from aquarium was tested for biochemical markers, including acetylcholinesterase (AChE), Glutathione S-Transferase (GST), Catalase (CAT) and malondialdehyde (MDA). After 96 hours, the LC50 was estimated to be 782.7 ppm. The findings on behaviours revealed that lead slows down species' activities. Lead concentratiom increased within the mussel body as the water lead level decreased. The value of AChE was inversely related to lead concentration. However, GST, CAT and MDA increased with lead exposure.

Research Progress on Novel Electrochemical Descaling Technology for Enhanced Hardness Ion Removal

In recent years, electrochemical descaling technology has gained widespread attention due to its environmental friendliness and ease of operation. However, its single-pass removal efficiency could be higher, severely limiting its practical application. To overcome the limitations of traditional electrochemical descaling processes, this paper first focuses on the separation efficiency of H+ and OH− in the scale removal process based on numerous recent research papers. It mainly emphasizes how innovative cathode design can enhance the efficiency and stability of electrochemical descaling. Furthermore, this paper explores the coupling of electrochemical processes with different water treatment technologies, such as the combination of electrodeposition with electrocoagulation, filtration crystallization, microfiltration, and electrodialysis, and how these methods synergistically enhance descaling effects. Additionally, this paper discusses potential future directions for electrochemical descaling technology, including innovations in scale expansion, material updates, process optimization, system integration, and automation. Finally, this paper analyzes the practical challenges of electrochemical descaling technology, such as cost, energy consumption, equipment durability, and environmental impact, and proposes solutions. The implementation of these strategies is expected to promote the commercialization of electrochemical descaling technology, making it more aligned with the sustainability requirements of industry and the environment.

Electrochemical Conversion of CO2 into Formate Boosted by In Situ Reconstruction of Bi-MOF to Bi2O2CO3 Ultrathin Nanosheets.

Substantial emissions of CO2 have presented formidable challenges for global climate dynamics. Electrochemical reduction of CO2 to produce formic acid (HCOOH) is considered to be a promising approach for achieving carbon neutrality. Nevertheless, the development of a catalyst exhibiting both high catalytic activity and selectivity toward desired products remains an arduous task. Herein, we report the synthesis of a unique porous bismuth-based MOF (Bi-BTC) through microwave-assisted agitation. The Bi-BTC MOF has a good catalytic performance in electrochemical CO2RR to formate products. At -0.9 V (vs RHE) potential, the Faradaic efficiency of formate can reach 96%, and the current density of the CO2RR is 25 mA/cm2. Bi-BTC also exhibits good electrochemical stability. FEformate and current density were maintained for 24 h with almost no attenuation. It was found that Bi-BTC was reconstructed in the CO2RR process. The shape of nanocolumn before electrolysis is transformed into an ultrathin nanosheet. The soft and hard acid-base theory (HSAB) proves that the reason for the reconfiguration is that the hard base ions (HCO3-) and the intermediate acid (Bi3+) break in the Bi-O bond in Bi-MOF, resulting in the transition of the original column structure of Bi-BTC to Bi2O2CO3 ultrathin nanosheeets. The DFT calculation shows that the restructured Bi2O2CO3 nanosheet exposes a crystal surface structure, which is conducive to lower the activation energy barrier of the electrochemical CO2RR intermediate *OCHO and stabilizing the reaction intermediate. Therefore, it is more beneficial to improve the selectivity of the electrochemical CO2RR to formate formation. This result proves that irreversible reconfiguration of catalyst is beneficial to electrochemical CO2RR. In addition, coupling a Bi-BTC cathode with a stable anode (IrO2) enables battery-driven high-activity CO2RR and an OER with good activity and efficiency.

Brackish groundwater desalination by constant current membrane capacitive deionization (MCDI): Results of a long-term field trial in Central Australia

A long-term field trial of membrane capacitive deionization (MCDI) was conducted in a remote community in the Northern Territory of Australia, with the aim of producing safe palatable drinking water from groundwater that contains high concentrations of salt and hardness ions and other contaminants. This trial lasted for 1.5 years, which, to our knowledge, is one of the longest reported studies of pilot-scale MCDI field trials. The 8-module MCDI pilot unit reduced salt concentration to below the Australian Drinking Water Guideline value of 600 mg/L total dissolved solids (TDS) concentration with a relatively high water recovery of 71.6 ± 8.7 %. During continuous constant current operation and electrode discharging at near zero volts, a rapid performance deterioration occurred that was primarily attributed to insufficient desorption of multivalent ions from the porous carbon electrodes. Performance could be temporarily recovered using chemical cleaning and modified operating procedures however these approaches could not fundamentally resolve the issue of insufficient electrode performance regeneration. Constant current discharging of the electrodes to a negative cell cut-off voltage was hence employed to enhance the stability and overall performance of the MCDI unit during the continuous operation. An increase in selectivity of monovalent ions over divalent ions was also attained by implementing negative voltage discharging. The energy consumption of an MCDI system with a capacity of 1000 m3/day was projected to be 0.40∼0.53 kWh/m3, which is comparable to the energy consumption of electrodialysis reversal (EDR) and brackish water reverse osmosis (BWRO) systems of the same capacity. The relatively low maintenance requirements of the MCDI system rendered it the most cost-efficient water treatment technology for deployment in remote locations. The LCOW of an MCDI system with a capacity of 1000 m3/day was projected to be AU$1.059/m3 and AU$1.146/m3 under two operational modes, respectively. Further investigation of particular water-energy trade-offs amongst MCDI performance metrics is required to facilitate broader application of this promising water treatment technology.