Removal of Cu(II) by sodium hexametaphosphate and nano zero-valent iron modified calcium bentonite: characteristic, adsorption performance and mechanism.

Cu (II) is a toxic heavy metal commonly identified in groundwater contaminants. Bentonite-based cutoff wall is the most used method in isolating and adsorbing contaminants, while the bentonite in it easily to fail due to Cu(II) exchange. This study synthesized a novel material through the modification of calcium bentonite (CaB) utilizing sodium hexametaphosphate (SHMP) and nano zero-valent iron (NZVI). The characteristics, adsorption performance, and mechanism of the NZVI/SHMP-CaB were investigated comprehensively. The results showed that SHMP can disperse CaB and reduce flocculation, while NZVI can be further stabilized without agglomeration. The best adsorption performance of NZVI/SHMP-CaB could be obtained at the dosage of 2% SHMP and 4% NZVI. The NZVI/SHMP-CaB exhibited an outstanding removal efficiency of over 60% and 90% at a high Cu(II) concentration (pH = 6, Cu(II) = 300 mg/L) and acidic conditions (pH = 3-6, Cu(II) = 50 mg/L), respectively. The adsorption of Cu(II) by NZVI/SHMP-CaB followed a pseudo-second-order kinetic model, and fitting results from the Freundlich isothermal model suggested that the adsorption process occurred spontaneously. Besides the rapid surface adsorption on the NZVI/SHMP-CaB and ion exchange with interlayer ions in bentonite, the removal mechanism of Cu(II) also involved the chemical reduction to insoluble forms such as Cu0 and Cu2O. The generated FePO4 covered the surface of the homogenized NZVI particles, enhancing the resistance of NZVI/SHMP-CaB to acidic and oxidative environments. This study indicates that NZVI/SHMP-CaB is a promising alternative material which can be used for heavy metal removal from contaminated soil and water.

Remediation of oily-produced water from high-salinity oilfield using a low-cost, high-alumina calcium bentonite hollow fiber membrane.

Discharging improperly treated oily-produced water (OPW) into the environment can have significant negative impacts on environmental sustainability. It can lead to pollution of water sources, damage to aquatic ecosystems and potential health hazards for individuals living in the affected areas. Ceramic hollow fiber membrane (CHFM) technology is one of the most effective OPW treatment methods for achieving high oil removal efficiency while maintaining membrane water permeability. In this study, low-cost calcium bentonite hollow fiber membranes (CaB-HFMs) were prepared from high-alumina calcium bentonite clay with various preparation parameters, including calcium bentonite content, sintering temperature, air gap distance and bore fluid rate. The prepared CaB-HFMs were then subjected to characterization using scanning electron microscopy (SEM), a three-point bending test, porosity, average pore size, hydraulic resistance and flux recovery ratio (FRR) analysis. Statistical analysis employing central composite design (CCD) assessed the interaction between the parameters and their effect on CaB-HFM water permeability and oil removal efficiency. Higher ceramic content and sintering temperature led to reduced porosity, smaller pore size and higher mechanical strength. In contrast, increasing the air gap distance and bore fluid rate exhibit different trends, resulting in higher porosity and pore size, along with weaker mechanical strength. Other than that, all of the CaB-HFMs displayed low hydraulic resistance (<0.01 m2 h.bar/L) and high FRR value (up to 95.2%). Based on CCD, optimal conditions for CaB-HFM were determined as follows: a calcium bentonite content of 50 wt.%, a sintering temperature of 1096 °C, an air gap distance of 5 cm and a bore fluid rate of 10 mL/min, with the desirability value of 0.937. Notably, the optimized CaB-HFMs demonstrated high oil removal efficiency of up to 99.7% with exceptional water permeability up to 535.2 L/m2.h.bar. The long-term permeation study also revealed it was capable of achieving a high average water permeation and a stable oil rejection performance of 522.15 L/m2.h.bar and 99.8%, respectively, due to their inherent hydrophilic and antifouling characteristics, making it practical for OPW treatment application.

Removal of cadmium and cobalt from water by Slovak bentonites: efficiency, isotherms, and kinetic study.

Slovak bentonite was used as an effective natural adsorbent for the removal of Cd(II) and Co(II). Characterization of the samples was conducted using X-ray diffraction (XRD), high-resolution scanning electron microscopy with an X-ray energy dispersion spectrometer (SEM-EDS), and infrared spectroscopy (FT-IR). Adsorption experiments were carried out for pure water and artificial seawater, each containing cobalt and cadmium cations within the concentration range of 5-60 mg/L. The highest bentonite adsorption capacities of the tested bentonites were 23.5 (Cd) and 32.2 (Co) mg g-1. The kinetics data revealed that, in addition to chemisorption, intraparticle diffusion contributes to metal removal. The physical and structural properties of bentonites play an important role in adsorption. Bentonite P 135 from the Lieskovec deposit showed the highest efficiency for removing both ions, with removal percentages exceeding 90% and 77.5% for pure water and artificial seawater, respectively. The results indicate the suitability of using Slovak bentonites as an alternative sorbent for both metal extractions. The mechanism of metal ion adsorption on bentonite clay can be understood through surface complexation and ion exchange. The examined bentonite deposits show potential as promising natural sorbents for the removal of cobalt and cadmium cations from polluted waters.

Design of saccharide based organic binder for low-grade iron ore pelletization using atomistic simulations and machine learning methods.

Inorganic binders like bentonite, used for pelletization of low-grade iron ore, generate iron ore slimes with comparatively high silica and alumina content necessitating extra steps for their removal during iron making process. This demands the usage of organic binders as full or partial replacement of bentonite for iron ore pelletization. In this work, adsorption of organic binders with saccharides skeleton and -H, -OH, -CH2OH and -CH2CH2OH as polar substituents, on goethite surface was studied using density functional theory, molecular dynamics and machine learning. It was observed that adsorption energy of binders on goethite surface had weak dependence on number of hydrogen bonds between them. With this favorable interaction in mind, a library containing 64 organic binders was constructed and adsorption energy of 30 of these binders was computed using molecular dynamics, followed by training of a linear regression model, which was then used to predict the adsorption energy of rest of the binders in the library. It was found that the introduction of -CH2CH2OH at R2 position resulted in statistically significant higher adsorption energy. Binder34 and Binder44 were identified as viable candidates for both goethite and hematite ore pelletization and adsorption of their n-mers on goethite and hematite surfaces was also quantified.

Recent advances in natural nanoclay for diagnosis and therapy of cancer: A review.

Cancer is still one of the deadliest diseases, and diagnosing and treating it effectively remains difficult. As a result, advancements in earlier detection and better therapies are urgently needed. Conventional chemotherapy induces chemoresistance, has non-specific toxicity, and has a meager efficacy. Natural materials like nanosized clay mineral formations of various shapes (platy, tubular, spherical, and fibrous) with tunable physicochemical, morphological, and structural features serve as potential templates for these. As multifunctional biocompatible nanocarriers with numerous applications in cancer research, diagnosis, and therapy, their submicron size, individual morphology, high specific surface area, enhanced adsorption ability, cation exchange capacity, and multilayered organization of 0.7-1 nm thick single sheets have attracted significant interest. Kaolinite, halloysite, montmorillonite, laponite, bentonite, sepiolite, palygorskite, and allophane are the most typical nanoclay minerals explored for cancer. These multilayered minerals can function as nanocarriers to effectively carry a variety of anticancer medications to the tumor site and improve their stability, dispersibility, sustained release, and transport. Proteins and DNA/RNA can be transported using nanoclays with positive and negative surfaces. The platform for phototherapeutic agents can be nanoclays. Clays with bio-functionality have been developed using various surface engineering techniques, which could help treat cancer. The promise of nanoclays as distinctive crystalline materials with applications in cancer research, diagnostics, and therapy are examined in this review.

Dissolved organic matter promoted hydroxyl radical formation and phenanthrene attenuation during oxygenation of iron-pillared montmorillonites.

The oxygenation of Fe(II)-bearing minerals for hydroxyl radicals (HO•) formation and contaminant attenuation receives increasing attentions. However, information on dissolved organic matter (DOM) with different types, concentrations, and molecular weights (MWs) in manipulating HO• formation and contaminant attenuation during mineral oxygenation remain unclear. In this study, four iron-pillared montmorillonites (IPMs) and two DOM samples [e.g., humic acids (HA) and fulvic acids (FA)] were prepared to explore the HO• formation and phenanthrene attenuation during the oxygenation of IPMs in the presence or absence of DOMs. Results showed that iron-pillared and high-temperature calcination procedures extended the interlayer domain of IPMs, which provided favorable conditions for a high HO• production from 1293 to 14537 µmol kg-1. The surface-absorbed/low crystalline Fe(Ⅱ) was the predominant Fe(Ⅱ) fractionations for HO• production, and presence of DOMs significantly enhanced the HO• production and phenanthrene attenuation. Moreover, regardless of the types and concentrations, the low MW (LMW, <1 kDa) fraction within DOM pool contributed highest to HO• production and phenanthrene attenuation, followed by the bulk and high MW (HMW-, 1 kDa∼0.45 µm) fractions, and FA exhibited more efficient effects in promoting HO• production and phenanthrene attenuation than HA. The fluorescent spectral analysis further revealed that phenolic-like fluorophores in LMW-fraction were the main substances responsible for the enhanced HO• production and phenanthrene attenuation. The results deepen our understandings toward the behaviors and fate of aquatic HO• and contaminants, and also provide technical guidance for the remediation of contaminated environments.

Polypyrrole-decorated bentonite magnetic nanocomposite: A green approach for adsorption of anionic methyl orange and cationic crystal violet dyes from contaminated water.

In the presented study, a novel polypyrrole-decorated bentonite magnetic nanocomposite (MBnPPy) was synthesized for efficient removal of both anionic methyl orange (MO) and cationic crystal violet (CV) dyes from contaminated water. The synthesis of this novel adsorbent involved a two-step process: the magnetization of bentonite followed by its modification through in-situ chemical polymerization. The adsorbent was characterized by SEM/EDX, TEM/SAED, BET, TGA/DTA-DTG, FTIR, VSM, and XRD studies. The investigation of the adsorption properties of MBnPPy was focused on optimizing various parameters, such as dye concentration, medium pH, dosage, contact time, and temperature. The optimal conditions were established as follows: dye concentration of Co (CV/MO) at 100 mg/L, MBnPPy dosage at 2.0 g/L, equilibrium time set at 105 min for MO and 120 min for CV, medium pH adjusted to 5.0 for MO dye and 8.0 for CV dye, and a constant temperature of 303.15 K. The different kinetic and isotherm models were applied to fit the experimental results, and it was observed that the Pseudo-2nd-order kinetics and Langmuir adsorption isotherm were the best-fitted models. The maximal monolayer adsorption capacities of the adsorbent were found to be 78.74 mg/g and 98.04 mg/g (at 303.15 K) for CV and MO, respectively. The adsorption process for both dyes was exothermic and spontaneous. Furthermore, a reasonably good regeneration ability of MBnPPy (>83.45%/82.65% for CV/MO) was noted for up to 5 adsorption-desorption cycles with little degradation. The advantages of facile synthesis, cost-effectiveness, non-toxicity, strong adsorption capabilities for both anionic and cationic dyes, and easy separability with an external magnetic field make MBnPPy novel.

pH-responsive bentonite nanoclay carriers control the release of benzothiazolinone to restrain bacterial wilt disease.

Ralstonia solanacearum (R. solanacearum) is one of the most devastating pathogens in terms of losses in agricultural production. Bentonite (Bent) is a promising synergistic agent used in development of effective and environmentally friendly pesticides against plant disease. However, the synergistic mechanism of Bent nanoclays with benzothiazolinone (BIT) against R. solanacearum is unknown. In this work, acid-functionalized porous Bent and cetyltrimethylammonium bromide (CTAB) were employed as the core nanoclays, and BIT was loaded into the clay to form BIT-loaded CT-Bent (BIT@CT-Bent) for the control of bacterial wilt disease. BIT@CT-Bent exhibited pH-responsive release behavior that fit the Fickian diffusion model, rapidly releasing BIT in an acidic environment (pH = 5.5). The antibacterial effect of BIT@CT-Bent was approximately 4 times greater than that of the commercial product BIT, and its biotoxicity was much lower than that of BIT under the same conditions. Interestingly, R. solanacearum attracted BIT@CT-Bent into the nanocomposites and induced cytoplasmic leakage and changes in membrane permeability, indicating an efficient and synergistic bactericidal effect that rapidly reduced bacterial density. In addition, BIT@CT-Bent significantly inhibited R. solanacearum biofilm formation and swimming activity, by suppressing the expression of phcA, solR and vsrC. Indeed, exogenous application of BIT@CT-Bent significantly suppressed the virulence of R. solanacearum on tobacco plants, with control effect of 75.48%, 72.08% and 66.08% at 9, 11 and 13 days after inoculation, respectively. This study highlights the potential of using BIT@CT-Bent as an effective, eco-friendly bactericide to control bacterial wilt diseases and for the development of sustainable crop protection strategies.

Exploring the Potential of Montmorillonite as an Antiproliferative Nanoagent against MDA-MB-231 and MCF-7 Human Breast Cancer Cells.

Unlike MCF-7 cells, MDA-MB-231 cells are unresponsive to hormone therapy and often show resistance to chemotherapy and radiotherapy. Here, the antiproliferative effect of biocompatible montmorillonite (Mt) nanosheets on MDA-MB-231 and MCF-7 human breast cancer cells was evaluated by MTT assay, flow cytometry, and qRT-PCR. The results showed that the Mt IC50 for MDA-MB-231 and MCF-7 cells in a fetal bovine serum (FBS)-free medium was ~50 and ~200 µg/mL, and in 10% FBS medium ~400 and ~2000 µg/mL, respectively. Mt caused apoptosis in both cells by regulating related genes including Cas-3, P53, and P62 in MDA-MB-231 cells and Bcl-2, Cas-8, Cas-9, P53, and P62 in MCF-7 cells. Also, Mt arrested MCF-7 cells in the G0/G1 phase by altering Cyclin-D1 and P21 expression, and caused sub-G1 arrest and necrosis in both cells, possibly through damaging the mitochondria. However, fewer gene expression changes and more sub-G1 arrest and necrosis were observed in MDA-MB-231 cells, confirming the higher vulnerability of MDA-MB-231 cells to Mt. Furthermore, MDA-MB-231 cells appeared to be much more vulnerable to Mt compared to other cell types, including normal lung fibroblast (MRC-5), colon cancer (HT-29), and liver cancer (HepG2) cells. The higher vulnerability of MDA-MB-231 cells to Mt was inferred to be due to their higher proliferation rate. Notably, Mt cytotoxicity was highly dependent on both the Mt concentration and serum level, which favors Mt for the local treatment of MDA-MB-231 cells. Based on these results, Mt can be considered as an antiproliferative nanoagent against MDA-MB-231 cells and may be useful in the development of local nanoparticle-based therapies.

Immobilization of recombinant Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) with montmorillonite for absorption and in situ degradation of aflatoxin B1.

Aflatoxin B1 is a highly carcinogenic and teratogenic substance mainly produced by toxin-producing strains such as Aspergillus flavus and Aspergillus parasitic. The efficient decomposition of aflatoxin is an important means to reduce its harm to humans and livestock. In this study, Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) was recombinantly expressed in Bacillus subtilis (B. subtilis) 168. MMT-CTAB-AFB1D complex was prepared by the immobilization of TV-AFB1D and montmorillonite (MMT) by cross-linking glutaraldehyde. The results indicated that TV-AFB1D could recombinantly express in engineered B. subtilis 168 with a size of approximately 77 kDa. The immobilization efficiency of MMT-CTAB-AFB1D reached 98.63% when the concentration of glutaraldehyde was 5% (v/v). The relative activity of TV-AFB1D decreased to 72.36% after reusing for 10 times. The content of AFB1 in MMT-CTAB-AFB1D-AFB1 decreased to 1.1 µg/g from the initial 5.6 µg/g after incubation at 50 °C for 6 h. The amount of 80.4% AFB1 in the MMT-CTAB-AFB1D-AFB1 complex was degraded by in situ catalytic degradation. Thus, the strategy of combining adsorption and in situ degradation could effectively reduce the content of AFB1 residue in the MMT-CTAB-AFB1D complex.

Engineered Clay-Polymer Composite for Biomedical Drug Delivery and Future Challenges: A Survey.

Clay materials are widely used in drug delivery systems due to their unique characteristics. Montmorillonite is a major component of bentonite and it has a large surface area, better swelling capacity, and high adsorption capacity. The modification of natural bentonite could improve its sorption ability for new emerging applications. Recent advancements in the polymer-silicate composite have novel biomedical applications in drug delivery, tissue regeneration, wound healing, cancer therapy, enzyme immobilization, diagnostic and therapeutic devices, etc. Perspective view of the montmorillonite- polymer composite as a pharmaceutical carrier in drug delivery systems has been discussed in this review. Different types of modification of montmorillonite for the development of pharmaceutical formulations have also been documented. Many challenges in clay nanocomposite systems of polymer of natural/synthetic origin are yet to be explored in improving antimicrobial properties, mechanical strength, stimuli responsiveness, resistance to hydrolysis, etc. Drug interaction and binding capability, swelling of clay may be carried out for finding possible applications in monitoring delivery systems. Pharmaceutical properties of active drugs in the formulation could also be improved along with dissolution rate, solubility, and adsorption. The clay-incorporated polymeric drug delivery systems may be examined for a possible increase in swelling capacity and residence time after mucosal administration.

Effect of alkali pretreatment time on kitchen waste anaerobic digestion performance enhanced by alkali pretreatment combined with bentonite: performance enhancement, microbial community structure, and functional gene analysis.

Kitchen waste was mainly composed of carbohydrates, lipids, and proteins. Anaerobic digestion (AD) of kitchen waste usually occurred acidification and further deteriorated. In our previous study, alkali pretreatment combined with bentonite (AP/Be) treatment was proved to enhance high solid AD of kitchen waste. However, effects of AP time on AP/Be were not yet studied. This study investigated the effects of AP time on AP/Be treatment on enhancing high solid AD. The results showed that compared with the control group, the cumulative methane production rate could be increased by 3.30 times (149.7 mL CH4/g VS) and the volatile solids (VS) reduction rate increased by 63.36%. Microbial community analysis showed that the relative abundance of Methanosarcina and Methanosaeta were increased from 6.49 and 7.83% to 47.14 and 16.39% respectively. Predictive functional analysis showed that AP/Be treatment increased the abundance of energy production and conversion, coenzyme transport, and metabolism. This study revealed the potential mechanism of AP/Be enhanced kitchen waste AD performance and AP/Be was a potential strategy to strengthen AD.

Functionality and mechanistic parametric study of the potential of waste plantain peels and commercial bentonite for soybean oil refining.

The consumption of unrefined vegetable oil poses acute and chronic health issues, yet improper disposal of waste plantain peels is not environmentally sustainable. This research investigates the feasibility, mechanism and thermodynamics of waste plantain peels, and commercial bentonite clay for soybean oil refining. Experiment was carried out using masses (1-4 g) of commercial bentonite clay, and unripe plantain peel ash (UPPA) to degummed and neutralized free fatty acid (FFA) contents in crude soybean oil at varying temperatures (50-120 °C), and time (15-35 min) for treatment of soybean oil. FTIR spectroscopy, SEM, and XRF techniques were applied to characterize the sample. The results established that at optimum 4.0 g dosage, the UPPA (97.73%) was more effective in the removal of FFA from oil at 50 °C and 20 min, while the clay (90%) was more effective in the removal of colour pigment from the vegetable oil 100 °C, and 25 min. The optimum efficiency of Clay-Ash-composite (70:30) in adsorbing pigment from soybean oil corresponds to 80%. The impact of changing viscosities, densities, and acid values on the performance of UPPA, clay, and clay-UPPA composite was investigated. Mechanistic studies confirmed the pseudo-second-order kinetics at 5 × 10-2 g/mg min-1 and 1.87 × 10-1 g/mg min-1, with corresponding adsorption capacity of 30.40 mg/g and 4.91 mg/g, at R2 ≤ 0.9982. The UPPA-driven sorption of FFA occurred as a physisorption and exothermic process (- 620.60 kJ/mol), while colour pigment removal occurred by chemisorption and endothermic process (22.40 kJ/mol). The finding recommends UPPA and composite as economically feasible for refining soybean oil.

Formation and sedimentation of oil-mineral aggregates in the presence of chemical dispersant.

The formation and sedimentation of oil-mineral aggregates (OMAs) is the major method to transport spilled oil to the seafloor. In this study, the formation and sedimentation experiments of OMA using montmorillonite and four crude oils were performed in a wave tank in the presence of chemical dispersant. Most of the formed OMAs were droplet OMAs, and single droplet OMA would aggregate into multiple ones under the action of the dispersant. The size of the oil droplets trapped in the OMA increased with time and was larger for the oil with higher viscosity. The sinking velocities of OMAs formed in this study were between 100-1200 µm s-1 and they were positively correlated with their diameter. The density of OMA was of the same order as that of the crude oil that formed them. An increase in the dispersant dosage could promote the formation of OMAs. The oil content in OMAs was higher for the denser oil in the presence of a dispersant. The maximum oil trapping efficiency of OMAs was 48.05%. This study provides fundamental data on the formation kinetics of OMAs.

Immobilization of phosphorus in water-sediment system by iron-modified attapulgite, calcite, bentonite and dolomite under feed input condition: Efficiency, mechanism, application mode effect and response of microbial communities and iron mobilization.

Four kinds of iron-based materials, i.e., iron-modified attapulgite, calcite, bentonite and dolomite (abbreviated as Fe-ATP, Fe-CA, Fe-BT and Fe-DOL, respectively) were prepared and used to immobilize the phosphorus in the system of overlying water (O-water) and sediment under the feed input condition, and their immobilization efficiencies and mechanisms were investigated. The influence of application mode on the immobilization of phosphorus in the water-sediment system by Fe-ATP, Fe-CA, Fe-BT and Fe-DOL was researched. The effects of Fe-ATP, Fe-CA, Fe-BT and Fe-DOL on the concentration of labile iron in the water-sediment system and the microbial communities in sediment were also studied. The results showed that the Fe-ATP, Fe-CA, Fe-BT and Fe-DOL addition all can effectively immobilize the soluble reactive phosphorus (SRP), dissolved total phosphorus (DTP) and diffusive gradients in thin-films (DGT)-labile phosphorus in O-water under the feed input condition, and also had the ability to inactivate the DGT-labile phosphorus in the top sediment. Although the change in the application mode from the one-time addition to the multiple addition reduced the inactivation efficiencies of SRP and DTP in O-water in the early period of application, it increased the immobilization efficiencies in the later period of application. Although Fe-ATP, Fe-CA, Fe-BT and Fe-DOL had a certain releasing risk of iron into the pore water, they had negligible risk of iron release into O-water. The addition of Fe-ATP, Fe-CA, Fe-BT or Fe-DOL reshaped the sediment bacterial community structure and can affect the microorganism-driven phosphorus cycle in the sediment. Results of this work suggest that Fe-ATP, Fe-CA, Fe-BT and Fe-DOL are promising phosphorus-inactivation materials to immobilize the phosphorus in the water-sediment system under the feed input condition.

Aluminosilicates as a Double-Edged Sword: Adsorption of Aflatoxin B1 and Sequestration of Essential Trace Minerals in an In Vitro Gastrointestinal Poultry Model.

Aflatoxins can cause intoxication and poisoning in animals and humans. Among these molecules, aflatoxin B1 (AFB1) is the most dangerous because of its carcinogenic and mutagenic properties. To mitigate these effects, clay adsorbents are commonly included in the diet of animals to adsorb the carcinogens and prevent their absorption in the gastrointestinal tract. In this study, four clays, three smectites (C-1, C-2, and C-3), and one zeolite (C-4), were compared as adsorbents of AFB1 and trace inorganic nutrients using an in vitro gastrointestinal model for poultry. Characterization of the clays using Fourier transform infrared spectroscopy revealed characteristic bands of smectites in C-1, C-2, and C-3 (stretching vibrations of Si-O, Al-O-Si, and Si-O-Si). The C-4 presented bands related to the bending vibration of structural units (Si-O-Si and Al-O-Si). X-ray diffraction analysis showed that C-1 is a montmorillonite, C-2 is a beidellite, C-3 is a beidellite-Ca-montmorillonite, and C-4 is a clinoptilolite. The elemental compositions of the clays showed alumina, silica, iron, calcium, and sodium contents. The cation exchange capacity was higher in C-3 clay (60.2 cmol(+)/kg) in contrast with the other clays. The AFB1 adsorption of C-1 was the highest (98%; p ˂ 0.001), followed by C-2 (94%). However, all the clays also sequestered trace inorganic nutrients (Fe, Mn, Zn, and Se). Both smectites, montmorillonite and beidellite, were the most suitable for use as adsorbents of AFB1.

Characterization of Olive Oil Volatile Compounds after Elution through Selected Bleaching Materials-Gas Chromatography-Mass Spectrometry Analysis.

Using different bleaching materials to eliminate or reduce organic volatiles in deteriorated olive oils will positively affect its characteristics. This study aims to identify the volatiles of oxidized olive oil after physical bleaching using selected immobilized adsorbents. Oxidized olive oil was eluted using open-column chromatography packed with silica gel, bentonite, resin, Arabic gum, and charcoal at a 1:5 eluent system (w/v, adsorbent: oxidized olive oil). The smoke point was determined. The collected distilled vapor was injected into GC-MS to identify the volatiles eluted after partial refining with each of these bleaching compounds. The results showed that volatile compounds were quantitatively and qualitatively affected by the type of adsorbents used for the elution of olive oil and the smoking points of eluted oils. The most prominent detected volatile compounds were limonene (14.53%), piperitone (10.35%), isopropyl-5-methyl-(2E)-hexenal (8.6%), methyl octadecenoate (6.57%), and citronellyl acetate (5.87%). Both bentonite and resin were superior in decreasing the ratio of volatile compounds compared with other bleaching materials used. Resin immobilized medium was significantly affected (p < 0.05), raising the smoke point. These results highlighted some information regarding the characteristics of volatile compounds that result after the physical elution of olive oil through selected adsorbents.

Andrographolide loaded montmorillonite attenuated enterotoxigenic Escherichia coli induced intestinal barrier injury and inflammation in a mouse model.

Montmorillonite (MMT), a natural absorbent agent, has widely been accepted for its antidiarrhea function in human and farm animals; however, its specific physicochemical property limits its biological function in practical use. In the current study, raw MMT was loaded by andrographolide, namely andrographolide loaded montmorillonite (AGP-MMT). The microstructure of AGP-MMT was observed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The effect of AGP-MMT on the growth performance, intestinal barrier and inflammation was investigated in an enterotoxigenic Escherichia coli (ETEC) challenged mice model. The results show that the microstructure of MMT was obviously changed after andrographolide modification: AGP-MMT exhibited a large number of spheroid particles, and floccule aggregates, but lower interplanar spacing compared with MMT. ETEC infection induced body weight losses and intestinal barrier function injury, as indicated by a lower villus height and ratio of villus height/crypt depth, whereas the serum levels of diamine oxidase (DAO), D-xylose and ETEC shedding were higher in the ETEC group compared with the CON group. Mice pretreated with AGP-MMT showed alleviated body weight losses and the intestinal barrier function injury induced by ETEC challenge. The villus height and the ratio of villus height/crypt depth, were higher in mice pretreated with AGP-MMT than those pretreated with equal levels of MMT. Pretreatment with AGP-MMT also alleviated the increased concentration of serum tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß), and the corresponding genes in the jejunum induced by ETEC infection in mice. The protein and mRNA levels of IL-1ß were lower in mice pretreated with AGP-MMT than those with equal levels of MMT. The results indicate that AGP-MMT was more effective in alleviating intestinal barrier injury and inflammation in mice with ETEC challenge than MMT.

Effect of soluble phosphate and bentonite amendments on lead and cadmium bioavailability and bioaccessibility in a contaminated soil.

Effect of commonly used heavy metal immobilizing agents on risks of soil heavy metals has not been well investigated. In this work, a contaminated acidic soil (total Cd = 8.05, total Pb = 261 mg kg-1) was amended with soluble phosphate (P: 160 mg kg-1) and bentonite (3 g kg-1) and incubated for 360 d. The soil was then added to mouse feed at 1:9 soil: feed ratio (weight) and fed to mouse for 10 days, after which the liver, kidney and bone Pb and Cd concentrations were measured. The amended soils were extracted with SBRC and PBET to assay bioaccessibility, and extracted with DTPA to assess the environmental availability. The amendments did not affect the DTPA-Pb/Cd significantly (p > 0.05), while the Cd bioaccessibility in the gastric phase of the SBRC assay was reduced from 90.0 to 20.4 % for the bentonite amended treatment (p < 0.05). Kidney Pb and Cd concentrations of the mice fed with feed containing phosphate spiked soil was 80.2 and 66.0 % lower than the control mice fed with unamended soil (CK), respectively. Significant linear correlations were found between DTPA-extractable concentration and kidney concentrations for Pb/Cd. The effect of amendment on Pb/Cd bioavailability differed between the results calculated with different endpoints. The phosphate amendment resulted in 82.7 and 34.3 % lower Pb RBA compared with the unamended soil calculated with kidney and kidney+liver+bone Pb concentrations, respectively, and 68.8 and 49.7 % lower Cd RBA than the control with kidney and kidney+liver concentrations, respectively. However, no significant effect was observed with both amendments when the RBA was calculated with liver or bone Pb/Cd concentrations, or on Pb RBA with kidney, liver or bone metal concentrations. Results indicate the complex effect of amendments on organ, tissue and overall health risk of soil Pb/Cd to animal/human.

Microplastics exhibit lower carrying effects on the bioaccessibility and cytotoxicity of lead than montmorillonite clay particles.

Microplastics (MPs) in the environment are always colonized by microbes, which may have implications for carrying effect of pollutants and exposure risk in organisms. We present the crucial impacts and mechanisms of microbial colonization on the bioaccessibility and toxicity of Pb(II) loaded in disposable box-derived polypropylene (PP) and polystyrene (PS) MPs and montmorillonite (MMT) clay particles. After 45 d incubation, higher biomass measured by crystal violet staining were detected in MMT (1.23) than in PP and PS (0.400 and 0.721) indicating preferential colonization of microbes in clay particles. Microbial colonization further enhanced the sorption ability toward Pb(II), but inhibited the desorption and bioaccessibility of enriched Pb(II) in zebrafish and decreased the toxicity to gastric epithelial cells in an order of MMT > PS ≈ PP. The crucial effects were mainly because microbe-colonized substrates possessed higher oxygen functional groups and specific surface area and exhibited stronger interactions with Pb(II) and digestive component (i.e., pepsin) than pure substrates. This decreased the available soluble pepsin for complexing with sorbed Pb(II). The findings highlight the role of microbial colonization in modulating the exposure risks of artificial and natural substrate-associated pollutants and suggest that the risks of MPs may be overestimated compared to clay particles.