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1.
Angew Chem Int Ed Engl ; : e202410210, 2024 Jul 18.
Article in English | MEDLINE | ID: mdl-39023074

ABSTRACT

Zn metal suffers from severe zinc dendrites, anion-related side reactions, hydrogen evolution reaction (HER) and narrow electrochemical stable window (ESW). Herein, an"anions-in-colloid" hydrated deep eutectic electrolyte (ACDE-3) is designed to improve the stability of zinc anode. The ACDE-3 reconfigures the hydrogen-bond (HB) network and regulates the solvation shell. More importantly, the hydroxyl-rich ß-cyclodextrins (ß-CDs) in ACDE-3 self-assemble into micelles, in which the steric effect between the adjacent ß-CDs restricts the movement of anions. This unique "anions-in-colloid" structure enables the eutectic system with a high Zn2+ transference number (tZn2+) of 0.84.  Thus, ACDE-3 inhibits the formation of dendrite, prevents the anion-involved side reactions, suppresses the HER, and enlarges the ESW to 2.32 V. The Zn//Zn symmetric cell delivers a long lifespan of 900 hours at 0.5 mAh cm-2, and the Zn//Cu half cells have a high average columbic efficiency (ACE) of 97.9% at 0.5 mAh cm-2 with a uniform and compact zinc deposition. When matched with a poly(1,5-naphthalenediamine) cathode, the full battery with a low negative/positive capacity ratio of 2 can still cycle steadily for 200 cycles at a current density of 1.0 A g-1. Additionally, this electrolyte can operative over a wide temperature range from -40 °C to 40 °C.

2.
J Colloid Interface Sci ; 675: 848-856, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-39002235

ABSTRACT

HYPOTHESIS: The scaling laws of drop pinch-off are known to be affected by drop compositions including dissolved polymers and non-Brownian particles. When the size of the particles is comparable to the characteristic length scale of the polymer network, these particles may interact strongly with the polymer environment, leading to new types of scaling behaviors not reported before. EXPERIMENTS: Using high-speed imaging, we experimentally studied the time evolution of the neck diameter hmin of drops composed of silica nanoparticles dispersed in PEO solution when extruded from a nozzle. FINDINGS: After initial Newtonian necking with hmin âˆ¼ t2/3, the subsequent stage may exhibit scaling variation, characterized by either exponential or power-law decay, depending on the nanoparticle volume fraction ϕ. The exponential decay hmin âˆ¼ e-t/τ signifies the coil-stretch transition in typical viscoelastic suspensions. We conducted an analysis of the power-law scenario hmin âˆ¼ tα at high ϕ, categorizing the entire process into three distinct regimes based on the exponents α. The dependences of critical thicknesses at transition points and exponents on polymer concentration offer initial insights into the potential transition from heterogeneous to homogeneous thinning in the mixture. This novel scaling variation bears implications for accurately predicting and controlling droplet fragmentation in industrial applications.

3.
ACG Case Rep J ; 11(7): e01415, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39006053

ABSTRACT

Patients with Lynch syndrome, most commonly associated with colorectal cancer, have an increased risk of developing other tumors including pancreatic ductal adenocarcinoma and precursor lesions, such as intraductal papillary mucinous neoplasms. Here, we present a case of a man in his early 20s who presented with a retroperitoneal mass involving the head of the pancreas. Following a pancreaticoduodenectomy combined with para-aortic lymphadenectomy, a pathologic diagnosis of colloid carcinoma, also known as mucinous noncystic carcinoma, of the pancreas was reported. Further testing established the diagnosis of Lynch syndrome. This case is unique because colloid carcinoma of the pancreas is rare and has never been reported as an initial presentation of Lynch syndrome.

4.
Angew Chem Int Ed Engl ; : e202410046, 2024 Jul 20.
Article in English | MEDLINE | ID: mdl-39032152

ABSTRACT

Fast-charging capability and calendar life are critical metrics in rechargeable batteries, especially in silicon-based batteries that are susceptible to sluggish Li+ desolvation kinetics and HF-induced corrosion. No existing electrolyte simultaneously tackles both these pivotal challenges. Here we report a microscopically heterogeneous covalent organic nanosheet (CON) colloid electrolyte for extremely fast-charging and long-calendar-life Si-based lithium-ion batteries. Theoretical calculations and operando Raman spectroscopy reveal the fundamental mechanism of the multiscale noncovalent interaction, which involves the mesoscopic CON attenuating the microscopic Li+-solvent coordination, thereby expediting the Li+ desolvation kinetics. This electrolyte design enables extremely fast-charging capabilities of the full cell, both at 8C (83.1% state of charge) and 10C (81.3% state of charge). Remarkably, the colloid electrolyte demonstrates record-breaking cycling performance at 10C (capacity retention of 92.39% after 400 cycles). Moreover, benefiting from the robust adsorption capability of mesoporous CON towards HF and water, a notable improvement is observed in the calendar life of the full cell. This study highlights the role of microscopically heterogeneous colloid electrolytes in enhancing the fast-charging capability and calendar life of Si-based Li-ion batteries. Our work offers fresh perspectives on electrolyte design with multiscale interactions, providing insightful guidance for the development of alkali-ion/metal batteries operating under harsh environments.

5.
Turk J Surg ; 40(1): 28-35, 2024 Mar.
Article in English | MEDLINE | ID: mdl-39036009

ABSTRACT

Objectives: Topical silver treatments and silver dressings are increasingly being utilized for the local treatment of wounds; nevertheless, the evidence for their usefulness is unclear. The aim of this study was to investigate the impact of conventional dressings and silver colloid dressing on diabetic foot ulcers (DFU) with and without compression therapy. Material and Methods: This prospective, double-blind experiment included 50 patients with non-ischemic DFUs, split into two groups of 25 patients each. The study was conducted for a period of six months. The primary endpoint was to evaluate the entire epithelialization (total healing) of all ulcers on the study leg. Results: The ulcer area significantly decreased in the colloidal silver group (67.77 ± 17.82%) compared to the conventional saline group (21.70 ± 23.52%). When compared to the conventional group, the colloidal silver group required considerably fewer days to reach the endpoint (23.15 ± 8.15 days vs. 48.35 ± 18.07 days), and by day 14, ulcer area reduction (from 100%) was greater (48% in the silver group vs. 89.69% in the conventional group). Conclusion: In managing DFUs, unstructured hydrogel wound dressings using silver colloids based on ionic silver are more effective than regular saline dressings since they heal wounds more quickly in fewer days while also drastically reducing ulcer areas over time.

6.
World Neurosurg ; 189: 211, 2024 Jun 19.
Article in English | MEDLINE | ID: mdl-38906468

ABSTRACT

Colloid cysts are nonneoplastic epithelial lesions arising from the roof of the third ventricle near the foramen of Monro. They comprise approximately 0.5% to 2% of all brain lesions.1-3 Surgical resection is the definitive treatment when indicated. The microsurgical approach is generally considered the "gold standard," but the endoscopic approach has been gaining popularity.4-6 The choice is usually based on a surgeon's preference and key image findings such as the presence of hydrocephalus. The advantage of an endoscopic approach is shorter operative time, faster recovery, and a more anterolateral approach to avoid manipulation on the fornix. The major drawback of the endoscopic approach was previously reported as a higher recurrence rate due to incomplete removal of the cyst capsule. However, it has been shown that the rate of capsule excision may be similar to that of microsurgery, ranging from 80 to 100%.7-14 The authors demonstrate an endoscopic resection of a recurrent colloid cyst with bimanual technique through parallel channels in a ventriculoscope. Video 1 highlights the critical steps involved in preserving both vascular and neural structures during the procedure.

7.
Angew Chem Int Ed Engl ; : e202408586, 2024 Jun 09.
Article in English | MEDLINE | ID: mdl-38853460

ABSTRACT

Understanding the properties of the precursor can provide deeper insight into the crystallization and nucleation mechanisms of perovskites, which is vital for the solution-process device performance. Herein, we conducted a detailed investigation into the photophysics properties of CsPbBr3 precursors in a broad concentration and various solvents. The precursor transformed from the solution state into the colloidal state and exhibited aggregation-induced emission character as the concentration increased. The aggregative luminescence from the precursors originates from the polybromide plumbous that is formed through the coordination of solvent molecules to the lead metal center. Two adducts with monodentate (PbBr2 ⋅ solvent) and bidentate (PbBr2 ⋅ 2solvent) ligands can be obtained, accompanied by emission with photoluminescence at 610 and 565 nm, respectively. Furthermore, the aggregative luminescence intensity and color could be regulated by changing the solvent and precursor ratio. Besides, we discussed the difference between the molecular aggregate in the organic system and the ionic aggregate in the inorganic system: the ionic aggregate is composed of solvated ions rather than individual molecules as in organic systems, which could possess properties that ions do not have. The fluorescence that is sensitive to Pb2+ coordination reported here could be applied to screen perovskite additives and judge the precursor aging.

8.
Carbohydr Polym ; 340: 122244, 2024 Sep 15.
Article in English | MEDLINE | ID: mdl-38858017

ABSTRACT

This study introduces a novel multi-functional double-layer intelligent packaging. It focuses on developing a dual-function system capable of real-time monitoring and freshness preservation. Specifically, cellulose nanocrystalline (CNC) was obtained through acid hydrolysis, and then CNC/soybean protein isolate (CNC/SPI) complex colloid particles were prepared via antisolvent method. These particles served as stabilizers to prepare oil-in-water (O/W) cinnamon essential oil Pickering emulsion (CSCEO). The CSCEO was then integrated into the emulsified hydrophobic layer of a konjac glucomannan (Kgm) matrix through intermolecular hydrogen bonding. Finally, alginate (Alg) matrix containing alizarin (Al) as an indicator was added to construct the bilayer structure using a layer-by-layer casting strategy. The inner layer Alg/Al was the pH/NH3-responsive indicator layer, while the outer layer Kgm/CSCEO acted as the high-barrier bacteriostatic layer. The obtained dual-function, double-layer film (Alg/Al-Kgm/CSCEO), which possesses a sensitive, reversible and rapid response towards pH/NH3, shows exceptional antibacterial and antioxidant properties, as well as excellent mechanical property, light-blocking capability and hydrophobicity. For monitoring and maintaining the actual freshness of shrimp, such a bilayer packaging displays smallest change of ∆E and TVB-N (18.65 mg/100 g) even after 72 h, which further highlighting its potential in enhancing food safety and extending shelf life.


Subject(s)
Alginates , Anti-Bacterial Agents , Food Packaging , Mannans , Seafood , Alginates/chemistry , Food Packaging/methods , Mannans/chemistry , Anti-Bacterial Agents/chemistry , Animals , Antioxidants/chemistry , Food Preservation/methods , Hydrophobic and Hydrophilic Interactions , Penaeidae/chemistry , Soybean Proteins/chemistry , Hydrogen-Ion Concentration , Escherichia coli/drug effects
9.
Surg Neurol Int ; 15: 179, 2024.
Article in English | MEDLINE | ID: mdl-38840593

ABSTRACT

Background: Colloid cysts are intracranial lesions originating from abnormalities in the primitive neuroepithelium folding of the third ventricle. Various surgical approaches have been explored for the management of colloid cysts, each carrying its own set of advantages and limitations. Tubular retractors developed recently alleviate retraction pressure through radial distribution, potentially offering benefits for colloid cyst resection. This study aims to introduce and assess a modified microsurgical method utilizing the tubular retractor for addressing colloid cysts. Methods: The study included a retrospective assessment of patients who had colloid cysts and who were treated between 2015 and 2023 by one experienced surgeon. The demographic, clinical, radiological, histological, and surgical data regarding these patients were evaluated. The patients were assessed using the colloid cyst risk score, indicating a risk for obstructive hydrocephalus. Results: The minimally invasive microsurgical approach was successfully applied to all 22 identified patients. No postoperative surgical complications were reported. Gross total resection was achieved in 21 (95.5%) patients. The early complication rate was 22.7% (n = 5). There were no postoperative seizures, permanent neurological deficits, or venous injuries. The average hospital stay was 3 days. There was no evidence of recurrence at an average follow-up length of 25.9 months. Conclusion: The transtubular approach is an effective, safe method for treating colloid cysts. It achieves complete cyst removal with minimal complications, offering the benefits of less invasiveness, improved visualization, and reduced tissue disruption, strengthening its role in colloid cyst surgery.

10.
Small ; : e2402920, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38864391

ABSTRACT

The controlled self-assembly of nanomaterials has been a great challenge in nanosynthesis, especially for hierarchical architectures with high complexity. Particularly, the structural design of Prussian blue (PB) series materials with robustness and fast nucleation is even more difficult. Herein, a self-sustained-release strategy based on the slow release of metal ions from coordination ions is proposed to guide the assembly of PB crystals. The key to this strategy is the slow release by ligand, which can create ultra-low concentrations of metal ions so as to provide the possibility to realize the surface charge manipulation of PB primary colloids. By adding electrolyte or changing the polarity of the solution, the surface charge regulation of PB colloid is realized, and the PB hierarchical structures with branch fractal structure (PB-BS), octahedral fractal structure, and spherical fractal structure are effectively constructed. This work not only achieves the designability of the PB structure, but also synchronizes the functionalization during the PB assembly growth process by in situ encapsulation of the effective catalytic active component L-Ascorbic acid. As a result, the assembled PB-BS exhibits greatly enhanced catalytic activity and selectivity in styrene oxidation with the selectivity of oxidized styrene increasing from 35.6% (PB) to 80.5% (PB-BS).

11.
Sci Total Environ ; 946: 174147, 2024 Oct 10.
Article in English | MEDLINE | ID: mdl-38909800

ABSTRACT

Environmental behaviors of heavy metal in soil are strongly influenced by seasonal freeze-thaw events at the mid-high altitudes. However, the potential impact mechanisms of freeze-thaw cycles on the vertical migration of heavy metal are still poor understood. This study aimed to explore how exogenous cadmium (Cd) migrated and remained in soil during the in-situ seasonal freeze-thaw action using rare earth elements (REEs) as tracers. As a comparison, soil which was incubated in the controlled laboratory (25 °C) was employed. Although there was no statistically significant difference in the Cd levels of different soil depths under different treatments, the original aggregate sources of Cd in the 5-10 cm and 10-15 cm soil layers differed. From the distributions of REEs in soil profile, it can be known that Cd in the subsurface of field incubated soil was mainly from the breakdown of >0.50 mm aggregates, while it was mainly from the <0.106 mm aggregates for the laboratory incubated soil. Furthermore, the dissolved and colloidal Cd concentrations were 0.47 µg L-1 and 0.62 µg L-1 in the leachates from field incubated soil than those from control soil (0.21 µg L-1 and 0.43 µg L-1). Additionally, the colloid-associated Cd in the leachate under field condition was mainly from the breakdown of >0.25 mm aggregates and the direct migration of <0.106 mm aggregates, while it was the breakdown of >0.50 mm and the direct migration of <0.106 mm aggregates for the soil under laboratory condition. Our results for the first time provided insights into the fate of exogenous contaminants in seasonal frozen regions using the rare earth element tracing method.

12.
Adv Sci (Weinh) ; 11(26): e2400147, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38704677

ABSTRACT

Crystallization of alloys from a molten state is a fundamental process underpinning metallurgy. Here the direct imaging of an intermetallic precipitation reaction at equilibrium in a liquid-metal environment is demonstrated. It is shown that the outer layers of a solidified intermetallic are surprisingly unstable to the depths of several nanometers, fluctuating between a crystalline and a liquid state. This effect, referred to herein as crystal interface liquefaction, is observed at remarkably low temperatures and results in highly unstable crystal interfaces at temperatures exceeding 200 K below the bulk melting point of the solid. In general, any liquefaction process would occur at or close to the formal melting point of a solid, thus differentiating the observed liquefaction phenomenon from other processes such as surface pre-melting or conventional bulk melting. Crystal interface liquefaction is observed in a variety of binary alloy systems and as such, the findings may impact the understanding of crystallization and solidification processes in metallic systems and alloys more generally.

13.
Adv Colloid Interface Sci ; 329: 103162, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38761601

ABSTRACT

This paper reviews the recent progress of small angle scattering (SAS) techniques, mainly including X-ray small angle scattering technique (SAXS) and neutron small angle scattering (SANS) technique, in the study of metal-organic framework (MOF) colloidal materials (CMOFs). First, we introduce the application research of SAXS technique in pristine MOFs materials, and review the studies on synthesis mechanism of MOF materials, the pore structures and fractal characteristics, as well as the spatial distribution and morphological evolution of foreign molecules in MOF composites and MOF-derived materials. Then, the applications of SANS technique in MOFs are summarized, with emphasis on SANS data processing method, structure modeling and quantitative structural information extraction. Finally, the characteristics and developments of SAS techniques are commented and prospected. It can be found that most studies on MOF materials with SAS techniques focus mainly on nanoporous structure characterization and the evolution of pore structures, or the spatial distribution of other foreign molecules loaded in MOFs. Indeed, SAS techniques take an irreplaceable role in revealing the structure and evolution of nanopores in CMOFs. We expect that this paper will help to understand the research status of SAS techniques on MOF materials and better to apply SAS techniques to conduct further research on MOF and related materials.

14.
J Contam Hydrol ; 264: 104369, 2024 May.
Article in English | MEDLINE | ID: mdl-38810412

ABSTRACT

A conceptual equilibrium-based mathematical model for colloid-associated contaminant transport has been developed to study the impact of the subsurface environment on contaminant transport through a three-dimensional, saturated, and homogeneous groundwater flow system with uniform flow. The kinetic model's critical limitation is dealing with the more significant number of parameters utilized upon application to larger scales in three-dimensional regions when a series of transport mechanisms are incorporated. Therefore, the present study is the first attempt to study the equilibrium approach in three-dimensional regions to avoid complexities in the model. The current study, however, shows that the mere existence of colloids does not indicate that contaminants will move more quickly; rather, it also depends on how the aqueous phase interacts with the static solid matrix, captured colloid particles, and mobile colloids as well as how colloids interact with stationary solid matrix phase. We noticed that the affinity of contaminants to immobile sorbents (stationary solid matrix and captured colloids) can reduce the transport even in the presence of colloids. Three-dimensional numerical experiments reveal that contaminants infiltrate more in the downward direction in the absence of colloids and can be distributed more in the longitudinal direction and less in the downward direction when colloids are present. The dual nature of colloids is espied here: first, colloids can remove pollutants from a specific area more quickly, and second, in a similar manner, colloids can pollute a specific region more quickly.


Subject(s)
Colloids , Groundwater , Models, Theoretical , Water Movements , Water Pollutants, Chemical , Colloids/chemistry , Groundwater/chemistry , Adsorption , Water Pollutants, Chemical/chemistry , Kinetics , Models, Chemical
15.
Intensive Care Med ; 50(6): 813-831, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38771364

ABSTRACT

PURPOSE: This is the first of three parts of the clinical practice guideline from the European Society of Intensive Care Medicine (ESICM) on resuscitation fluids in adult critically ill patients. This part addresses fluid choice and the other two will separately address fluid amount and fluid removal. METHODS: This guideline was formulated by an international panel of clinical experts and methodologists. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was applied to evaluate the certainty of evidence and to move from evidence to decision. RESULTS: For volume expansion, the guideline provides conditional recommendations for using crystalloids rather than albumin in critically ill patients in general (moderate certainty of evidence), in patients with sepsis (moderate certainty of evidence), in patients with acute respiratory failure (very low certainty of evidence) and in patients in the perioperative period and patients at risk for bleeding (very low certainty of evidence). There is a conditional recommendation for using isotonic saline rather than albumin in patients with traumatic brain injury (very low certainty of evidence). There is a conditional recommendation for using albumin rather than crystalloids in patients with cirrhosis (very low certainty of evidence). The guideline provides conditional recommendations for using balanced crystalloids rather than isotonic saline in critically ill patients in general (low certainty of evidence), in patients with sepsis (low certainty of evidence) and in patients with kidney injury (very low certainty of evidence). There is a conditional recommendation for using isotonic saline rather than balanced crystalloids in patients with traumatic brain injury (very low certainty of evidence). There is a conditional recommendation for using isotonic crystalloids rather than small-volume hypertonic crystalloids in critically ill patients in general (very low certainty of evidence). CONCLUSIONS: This guideline provides eleven recommendations to inform clinicians on resuscitation fluid choice in critically ill patients.


Subject(s)
Critical Care , Critical Illness , Crystalloid Solutions , Fluid Therapy , Resuscitation , Humans , Fluid Therapy/methods , Fluid Therapy/standards , Critical Illness/therapy , Adult , Critical Care/methods , Critical Care/standards , Crystalloid Solutions/administration & dosage , Crystalloid Solutions/therapeutic use , Resuscitation/methods , Resuscitation/standards , Europe , Albumins/therapeutic use , Albumins/administration & dosage , Sepsis/therapy
16.
Small ; : e2402531, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38727180

ABSTRACT

The efficacy of electron transport layers (ETLs) is pivotal for optimizing the device performance of perovskite photovoltaic applications. However, colloidal dispersions of SnO2 are prone to aggregation and possess structural defects, such as terminal-hydroxyls (OHT) and oxygen vacancies (VOs), which can degrade the quality of ETLs, impede charge extraction and transport, and affect the nucleation and growth processes of the perovskite layer. In this study, the Sb(OH)4 - ions hydrolyzed from SbCl3 in colloidal dispersion can bind to defect sites and effectively stabilize the SnO2 nanocrystals are demonstrated. Upon oxidative annealing, a Sb2O5@SnO2 composite film is formed, in which the Sb2O5 not only mitigates the aforementioned defects but also broadens the energy range of unoccupied states through its dispersed conduction band. The increased electron affinity (EA) facilitates more efficient capture of photoexcited electrons from the perovskite layer, thus augmenting electron extraction and minimizing electron-hole recombination. As a result, a significant improvement in power conversion efficiency (PCE) from 22.60% to 24.54% is achieved, with an open circuit voltage (VOC) of up to 1.195 V, along with excellent stability of unsealed devices under various conditions. This study provides valuable insights for the understanding and design of ETLs in perovskite photovoltaic applications.

17.
J Colloid Interface Sci ; 668: 599-606, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-38691968

ABSTRACT

HYPOTHESIS: The formation of soft colloidal crystals, which are nonclose-packed ordered arrays of colloidal particles suspended in a solvent, is dictated by a single physical factor that yields a fixed threshold at order-disorder boundaries for different experimental conditions such as ion concentration, solvent type, and particle size. Identifying the determinant factor and its threshold value should enable the prediction of the critical concentrations of colloidal particles to form soft colloidal crystals. EXPERIMENTS: Soft colloidal crystals were fabricated using a series of monohydric alcohols as dispersion media and reflectance spectra were measured to locate order-disorder boundaries. The interaction forces acting between particles were also measured by employing atomic force microscopy. FINDINGS: The interparticle forces at the order-disorder boundaries exhibited a universal threshold that was independent of the solvent types including alcohols and water. Therefore, the determinant factor for the formation of soft colloidal crystals was determined to be the force acting between the particles. Furthermore, a priori calculation of this critical force and consequently the critical particle concentration in colloidal systems was demonstrated by referring to the pressure at the liquid-to-solid transition in a hard sphere system (Alder transition).

18.
Materials (Basel) ; 17(9)2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38730840

ABSTRACT

Attapulgite (APT) is widely used in wastewater treatment due to its exceptional adsorption and colloidal properties, as well as its cost-effectiveness and eco-friendliness. However, low-grade APT generally limits its performance. Here, a colloid mill-assisted ultrasonic-fractional centrifugal purification method was developed to refine low-grade APT. This process successfully separated and removed impurity minerals such as quartz and dolomite from the raw ore, resulting in a refined APT purity increase from 16.9% to 60% with a specific surface area of 135.5 m2∙g-1. Further modifying of the refined APT was carried out through the hydrothermal method using varying dosages of cetyltrimethylammonium chloride (CTAC), resulting in the production of four different APT adsorbents denoted as QAPT-n (n = CTAC mole number) ranging from 0.5 to 5 mmol. Using Congo red (CR) as the target pollutant, the QAPT-5 sample exhibited the best adsorption capacity with the maximum quantity of 1652.2 mg∙g-1 in a neutral solution at 30 °C due to the highest surface charge (zeta potential = 8.25 mV). Moreover, the QAPT-5 pellets (~2.0 g adsorbent) shaped by the alginate-assisted molding method removed more than 96% of 200 mL aqueous solution containing 200 mg∙L-1 CR and maintained this efficiency in 10 adsorption-elution cycles, which exhibited the promising practical application.

20.
Chemosphere ; 359: 142200, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38697565

ABSTRACT

Mg(OH)2 dissolves slowly and can provide a long-term source of alkalinity, thus a promising alternative reagent for the in situ remediation of heavy metal polluted groundwater. Unfortunately, it exhibits a relatively poor stabilization effect on heavy metal Cd due to the higher solubility of the resulting stabilized product, Cd(OH)2. To overcome this limitation, we investigated the use of MgCO3/Mg(OH)2 colloid modified by sodium polyacrylate (PAAS) to remove Cd from groundwater. Through ultrasonic dispersion, the molecular chains of PAAS are broken, causing a transformation from flocculation to surface modification, resulting in the production of a stable colloid. The colloidal particles of MgCO3/Mg(OH)2 have a smaller size and a negatively charged surface, which significantly enhances their migration ability in aquifers. The combination of MgCO3 and Mg(OH)2 provides a complementary effect, where MgCO3 effectively precipitates Cd in the aquifer while Mg(OH)2 maintains the required pH level for stabilization. The optimal compounding ratio of MgCO3 to Mg(OH)2 for achieving the best stabilization effect on Cd is found to be 1:1. Column experiments demonstrate that the injection of MgCO3/Mg(OH)2 colloid substantially enhances Cd stability, reducing the exchangeable fraction of Cd in aquifer media from 88.61% to a range of 22.50-34.38%. Based on these results, the MgCO3/Mg(OH)2 colloid shows great potential as a reactive medium for remediating Cd-contaminated groundwater.


Subject(s)
Cadmium , Colloids , Environmental Restoration and Remediation , Groundwater , Water Pollutants, Chemical , Groundwater/chemistry , Water Pollutants, Chemical/chemistry , Cadmium/chemistry , Colloids/chemistry , Environmental Restoration and Remediation/methods , Hydrogen-Ion Concentration , Flocculation , Acrylic Resins/chemistry
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