Adsorption behaviors of aflatoxin B1 and zearalenone by organo-rectorite modified with quaternary ammonium salts

Adsorption of aflatoxin B1 to corn by-products

The adsorption of aflatoxin B1 (AFB1) to natural fiber materials prepared from corn by-products was investigated in this study. The results showed that corn cob powder (CCP) dose, particle size, time (0.25-24 h), temperature (4, 20, 37, 50 and 100 °C) and pH (2-8), had significant effects on adsorption. The maximum adsorption (98%) was with particles 500-355 µm in size at 20 °C for 8 h, at the dose of 50 mg mL-1. The adsorption fitted pseudo-second-order model and Langmuir isotherm well. Besides, CCP had a higher adsorption capacity to AFB1 than any single cell wall components of corn, which indicated that capillary effect happened in cell wall might be the main reason for adsorption. The results also suggested that CCP could reduce AFB1 content from both liquid and solid food matrixes. Briefly, CCP displayed promising properties that could be developed in nature-based practical applications for food aflatoxin decontamination.

Synthesis of Castor Oil-Based Quaternary Ammonium Salt and Modification of Attapulgite for Treating Industrial Wastewaters

In order to develop multifunctional quaternary ammonium salts and explore their advantages as modifiers for wastewater treatment, castor oil-based quaternary ammonium salts were synthesised and subsequently used as modifiers for attapulgite treatment. The structures of untreated and treated attapulgite were compared by Fourier transform infrared spectra and X-ray diffraction. The mechanism of modification was speculated. Various factors such as the amount of modified attapulgite, temperature and pH were also investigated in the batch experiments on the removal rates of acetone and phenol from wastewaters. The synthesis conditions were set as follows: the reaction temperature was 80 °C, the reaction time was 8 h, the molar ratio of castor oil to N,N-dimethyl-1,3-propanediamine was 1:5, the catalyst was 6% NaOH and the product yield was about 64.72%. The grafting rate of the castor oil-based quaternary ammonium salt was about 99.6% when the amount of modifier was 0.69 g per 5 g of attapulgite, the ultrasound treatment time was 11 min and the pH was 5. The quaternary ammonium salt was only associated with the surface of attapulgite and did not change the rod-like crystal structure of the silicate. The modified attapulgite is much more fibrous and exhibits a good distribution of crystal bundles. The removal rates were found to be less favourable under strongly acidic and strongly alkaline conditions. Under suitable conditions, for 50 mL industrial wastewaters (phenol: 100-160 mg/L; acetone: 680-800 mg/L), the amount of modified attapulgite was 1 g, the temperature was 80 °C and the pH was 7, and the maximum removal rates of acetone and phenol after 80 min reached about 65.71% and 78.72%, respectively, which were higher than those of ATP.

Removal of Aflatoxin B1 and Zearalenone in Mixed Aqueous Solution by Palygorskite-Montmorillonite Materials In Situ Prepared from Palygorskite Mineral

In view of the animal feeds inevitably contaminated by multiple mycotoxins, eco-friendly and efficient palygorskite-montmorillonite (Pal-Mt) materials were prepared to remove polar aflatoxin B₁ (AFB₁) and weak polar zearalenone (ZEN) from mixed mycotoxins aqueous solution. The adsorption properties and bonding mechanisms between Pal-Mt materials and mycotoxins (AFB₁ and ZEN) were investigated systematically. The as-prepared Pal-Mt showed excellent adsorption capacity for AFB₁ and ZEN in single- and binary-mycotoxin systems, indicating the effectiveness of Pal-Mt acting as multiple mycotoxin adsorbents. The kinetics of adsorption for ZEN was fast due to the adsorption on the external surface (film and intraparticle diffusion), while AFB₁ molecules permeated into mesopores after the external adsorption for the more planar structure. Adsorption isotherms demonstrated that heterogeneous surface adsorption appeared between Pal-Mt and AFB₁, and monolayer adsorption occurred on Pal-Mt and ZEN for different polarities of mycotoxins. Thermodynamic parameters illustrated that the adsorption process of both AFB₁ and ZEN onto Pal-Mt was spontaneous and endothermic. The adsorption mechanism studies suggested that hydrogen bonding, electrostatic attraction, calcium bridging linkage, and ion-dipole played fundamental roles in the interaction between Pal-Mt and these two mycotoxins.

Adsorptive removal of aflatoxin B1 from vegetable oils via novel adsorbents derived from a metal-organic framework

Vegetable oils are essential daily diet, but they are simply contaminated with aflatoxin B₁ (AFB₁), a serious toxic compound to human health. Adsorption method due to the easy operation, high efficiency and low costing is set to become a main detoxification technique for AFB₁. Unfortunately, previous reported adsorbents were rarely used for detoxification in food industry since they cannot meet the criteria of large-scale production of edible oils. Metal-organic frameworks (MOFs) with unique textural properties could be favorable precursors for synthesis of advanced materials. In this research, three kinds of Cu-BTC MOF-derived porous materials were prepared by different carbonization temperature and characterized by XRD, SEM, FT-IR, and nitrogen adsorption-desorption techniques. Isotherm and kinetic studies on the adsorption behaviour of AFB₁ onto the three porous carbonaceous materials have been systematically conducted. The results revealed that the porous carbonaceous materials could act as the excellent adsorbents that were of enough adsorption sites for AFB₁, mainly due to the hierarchical porous structure and large surface areas for the enhancement of adsorption capacity. Notably, the porous carbonaceous materials could not only remove more than 90% of AFB₁ from real vegetable oils within 30 min, but also remain the treated oils at low cytotoxicity. Meanwhile, the detoxification process could little affect the quality of oils. Thus, the Cu-BTC MOF-derived porous carbonaceous materials with high efficiency, safe, practical and economic characteristics could be novel potential adsorbents used in the application of AFB₁ removal from contaminated vegetable oils.

Occurrence, Impact on Agriculture, Human Health, and Management Strategies of Zearalenone in Food and Feed: A Review

Mycotoxins represent an assorted range of secondary fungal metabolites that extensively occur in numerous food and feed ingredients at any stage during pre- and post-harvest conditions. Zearalenone (ZEN), a mycotoxin categorized as a xenoestrogen poses structural similarity with natural estrogens that enables its binding to the estrogen receptors leading to hormonal misbalance and numerous reproductive diseases. ZEN is mainly found in crops belonging to temperate regions, primarily in maize and other cereal crops that form an important part of various food and feed. Because of the significant adverse effects of ZEN on both human and animal, there is an alarming need for effective detection, mitigation, and management strategies to assure food and feed safety and security. The present review tends to provide an updated overview of the different sources, occurrence and biosynthetic mechanisms of ZEN in various food and feed. It also provides insight to its harmful effects on human health and agriculture along with its effective detection, management, and control strategies.

Assessing the Aflatoxins Mitigation Efficacy of Blueberry Pomace Biosorbent in Buffer, Gastrointestinal Fluids and Model Wine

Blueberry (BB) and cherry pomace were investigated as new biosorbents for aflatoxins (AFs) sequestration from buffered solutions, gastrointestinal fluids and model wine. Among the tested biosorbents, BB exhibited the maximum adsorption performance for AFs and hence was further selected for the optimization of experimental parameters like pH, dosage, time and initial concentration of AFs. Material characterizations via scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption-desorption isothermal studies, thermogravimetric analysis (TGA) and X-ray photon spectroscopy (XPS) techniques revealed useful information about the texture and chemical composition of the biosorbents. The fitting of isothermal data with different models showed the model suitability trend as: Sips model > Langmuir model > Freundlich model, where the theoretical maximum adsorption capacity calculated from the Sips model was 4.6, 2.9, 2.7 and 2.4 mg/g for AFB1, AFB2, AFG1 and AFG2, respectively. Kinetics study revealed the fast AFs uptake by BB (50-90 min) while thermodynamics studies suggested the exothermic nature of the AFs adsorption from both, single as well as multi-toxin buffer systems, gastrointestinal fluids and model wine. Accrediting to the fast and efficient adsorption performance, green and facile fabrication approach and cost-effectiveness, the newly designed BB pomace can be counted as a promising contender for the sequestration of AFs and other organic pollutants.

Functionalized nanoflower-like hydroxyl magnesium silicate for effective adsorption of aflatoxin B1

Aflatoxin B1 (AFB1), which is widely found in food and feed, poses a serious threat to the health of human and livestock. In this work, functionalized nanoflower-like hydroxyl magnesium silicate (FNHMS) was synthesized for adsorption of AFB1. First, bulk magnesium silicate (MS) was converted into nanoflower-like hydroxyl magnesium silicate (NHMS) by hydroxylation. Cetyltrimethylammonium bromide (CTMAB) modification then enhanced the hydrophobicity and the affinity to AFB1 of NHMS. The adsorption performance for AFB1 followed the order of MS < NHMS < FNHMS, and the adsorption performance increased with the increase of the dose of CTMAB. Isothermal adsorption analysis indicated that the surface of FNHMS was heterogeneous. The adsorption capacity of FNHMS-0.4 to AFB1 was estimated to be 27.34 mg g^-1 and 28.61 mg g^-1 by Freundlich and Dubinin-Radushkevich isotherm adsorption model, respectively. By analyzing the adsorption kinetics and adsorption thermodynamics, both physical adsorption and chemisorption existed in the process of AFB1 being adsorbed on FNHMS-0.4. Adsorption mechanisms analysis indicated that the adsorption followed the adsorption site priority of H > O > Mg. This work demonstrates that FNHMS could be a promising adsorbent for removal of AFB1.

Investigations on organo-montmorillonites modified by binary nonionic/zwitterionic surfactant mixtures for simultaneous adsorption of aflatoxin B1 and zearalenone

To solve the problem of simultaneous adsorption of polar and weak polar mycotoxins, organo-montmorillonites modified by binary surfactant mixtures (NZMts), including polyoxyethylene ether (OP-10) and lauramidopropyl betaine (LAB-35), were synthesized for the simultaneous removal of aflatoxin B₁ (AFB₁) and zearalenone (ZER). The microstructure, interface and pore structure characteristics of NZMts were investigated through different technologies. The results show that the obtained NZMts modified by binary surfactant mixtures have different structural configurations, higher carbon content and stronger hydrophobicity compared with organo-montmorillonites modified by single surfactant. More importantly, the obtained adsorbents show significant improvements on the detoxification efficiency of both AFB₁ and ZER. The pH has less effect on the adsorption of NZMts compared with the control samples modified by single surfactant, suggesting that NZMts are more stable in different pH environments. In addition, the adsorption mechanisms of NZMts to AFB₁ and ZER were proposed based on the characterizations and adsorption isotherms. It is indicated that NZMts combines with AFB₁ mainly through the hydrophobic interaction and ion dipole action, while with ZER mainly through hydrophobic interaction. The as-received NZMts with more hydrophobic property effectively enhance the adsorption capacities of weak polar and non-polar mycotoxins, providing a new orientation for multifunctional mycotoxin adsorbents.

The synergistic effect and microscopic mechanism of co-adsorption of three emerging contaminants and copper ion on gemini surfactant modified montmorillonite

Montmorillonite (G-Mt) modified by a gemini quaternary ammonium cationic surfactant (Propyl bis (hexadecyl dimethyl ammonium) chloride, 16-3-16) was used to remove emerging contaminants (ECs) (such as 1H-Benzotriazole (BTA), 5-Methyl-1H-benzotriazole (TTA) and 1-Hydroxybenzotriazole (HOBT)) and Cu²⁺ from wastewater. Based on the adsorption of the above three ECs in our previous studies, single adsorption of Cu²⁺ and the simultaneous adsorption of three ECs with Cu²⁺ on G-Mt were also investigated. G-Mt showed much lower adsorption amount on Cu²⁺ comparing with original montmorillonite (Ca-Mt) in single adsorption system due to the difficulty of ion-exchange property of G-Mt. In co-adsorption system, three organic pollutants and Cu²⁺ played a synergistic effect and the adsorption capacity of G-Mt on them increased, the influence sequence of Cu²⁺ on the adsorption of three ECs or the effect of ECs on the adsorption of Cu²⁺ both followed as: TTA > BTA > HOBT. The results of FT-IR, EDS and XPS revealed that the complex of Cu²⁺ and ECs were adsorbed onto G-Mt via forming complexes and hydrophobic interaction in co-adsorption system. The pH experiment showed that the optimum pH of the co-adsorption of ECs and Cu²⁺ on G-Mt was 5. Molecular dynamics (MD) simulations showed that three ECs or ECs combining with Cu²⁺ were dominantly adsorbed in the interlayer space of G-Mt, which resulted in the arrangement manner of 16-3-16 between the layer of G-Mt before and after adsorption of three organic pollutants was different. Furthermore, by quantitatively analyzing electrostatic potential (ESP) distribution, average local ionization energy (ALIE) distribution and their minimum points on three ECs molecules surfaces, Multiwfn program has been applied to probe the microscopic mechanism. The synergistic effect of co-adsorption will promote enrichment of copper ions and ECs to remove them more efficiently in polluted waters.

Design and synthesis of organic rectorite-based composite nanofiber membrane with enhanced adsorption performance for bisphenol A

Nowadays, most of mineral-based adsorbents are powder form, which makes them inconvenient to collect and always easy to cause secondary pollution. In this work, an organic rectorite composite nanofiber membrane (SRt-PAN) was designed and prepared by electrospinning technique. The as-received composite nanofiber membranes were characterized by XRD and SEM analysis, proving the homodisperse and existence of SRt in PAN nanofiber membrane. A series of batch experiments for BPA adsorption were carried out to investigate the effect of different adsorption parameters, including initial concentration, pH, and temperature of pollutant solution. The influences of modifier dosage and adsorbent dosage on the adsorption performance were investigated as well. On the basis of the experiment results, the adsorption process could be well described by the pseudo-second-order model and the Langmuir isotherm. In addition, the thermodynamic parameters indicate that this adsorption process is exothermic and spontaneous. Moreover, compared with pure nanofiber membranes and organic rectorite powders, the resultant SRt-PAN adsorbents exhibited higher adsorption capacity, superior reusability, and adsorption stability. It is indicated that the hydrophobicity surface of organic rectorite should be the key factor to not only the intimate interfacial combination between the mineral and PAN, but also the enhancement of BPA adsorption capacity.

Biosorptive detoxification of zearalenone biotoxin by surface-modified renewable biomass: process dynamics and application

BACKGROUND

Contamination of food, feed, beverages and even drinking water with biotoxins is a growing global concern because of their potential health risks. In this work, surface-modified sugar beet pulp waste was used for the biosorptive removal of zearalenone biotoxin from contaminated aquatic media.

RESULTS

Infrared, Boehm titration, BET (Brunauer-Emmett-Teller) surface area and point of zero charge analysis were employed for surface characterization. Kinetic and equilibrium studies showed that biotoxin biosorption was well predicted by the pseudo-second-order kinetic model and the Langmuir isotherm model. Zearalenone was removed from the solution over a wide pH range (3.0-8.0) and within a short time (15 min). Maximum uptake capacity of modified biomass was recorded as 23.30 ± 0.17 g kg^-1 . Highest removal yield in a dynamic flow mode (94.56 ± 0.13%) was achieved at 2 mL min^-1 flow rate using 30 mg biosorbent. Regeneration experiments revealed high reusability potential of suggested biosorbent. Moreover, its application potential was tested in spiked samples of malt, beer and canned corn liquid.

CONCLUSION

Detoxification potential of this renewable biomass was significantly enhanced after modification. Modified biomass could be used as an efficient and low-cost green-type material with good application potential for zearalenone detoxification. © 2018 Society of Chemical Industry.

Zearalenone and its metabolites: Effect on human health, metabolism and neutralisation methods

Mycotoxins are natural compounds produced as secondary metabolites by mold fungi belonging mainly to the Fusarium family, commonly found on plants such as corn or small grains in the temperate climate zone. One of these mycotoxins is zearalenone, which is classified as a xenoestrogen, an exogenous compound which resembles the structure of naturally occurring estrogens with its chemical structure. This property of zearalenone determines its ability to bind to estrogen receptors of cell and its bioaccumulation. This leads to disorders of the hormonal balance of the body, which in consequence may lead to numerous diseases of reproductive system such as prostate, ovarian, cervical or breast cancers. High risk posed by long-term exposure to contaminated food forces the modern science to develop and implement effective methods of zearalenone neutralisation. This work is a review of current state of knowledge on toxic effects of zearalenone, its metabolism in biological systems and proposed methods of its neutralisation.