Zearalenone (ZEA), a common contaminant in food and feedstuffs, threatens human and animal health. The present study aimed to investigate the protective effects of modified palygorskite (MPal), a ZEA-targeted adsorbent, on broilers (young chickens) fed a ZEA-contaminated diet. Broilers were subjected to one of three treatments for a period of 42 days: a basal diet (control group), a ZEA- contaminated diet, and a ZEA-contaminated diet supplemented with 1 g/kg of MPal. Blood was collected for serum metabolite assay, and liver and kidney were sampled to determine ZEA residue and antioxidant-related parameters, using commercial spectrophotometric kits. Compared with the basal diet, the ZEA- contaminated diet resulted in compromised growth performance (reduced daily gain and feed intake during finisher period), disordered relative liver weight (decreased at 21 days but increased at 42 days), increased ZEA residue in liver and kidney, abnormal serum metabolites (decreased total protein content but increased alanine aminotransferase activity at 21 and 42 days, reduced albumin content at 21 days, and elevated aspartate aminotransferase activity at 42 days), and disrupted antioxidant capacities of broilers (increased total superoxide dismutase (T-SOD) activity in liver at 21 and 42 days, decreased T-SOD activity in kidney at 21 and 42 days, and in serum at 42 days, greater malondialdehyde accumulation in liver and kidney at 42 days, and lower glutathione content in kidney at 21 days). The adverse consequences resulting from the ZEA-contaminated diet were relieved by the supplementation of MPal (except albumin concentration in serum and T-SOD activity in liver at 21 days), with the values of growth-performance parameters, liver weight, renal ZEA accumulation, total protein content, transaminase activity at 42 days, and antioxidant indexes being similar to those in the control group. These results suggested that MPal supplementation could promote growth performance, attenuate liver damage, and improve the antioxidant abilities of broilers fed ZEA-contaminated diet by reducing ZEA accumulation.

The present report is a review of uses of quaternary ammonium cations (QACs) as free monomers or immobilized in micelle-clay complexes in bacteria removal from water. The removal of bacteria from water by filtration through a bed of a granulated QAC-clay micelle was improved by minute concentrations of QAC that were released from the complex during filtration, which exerted biostatic or biocidal effects on the bacteria that emerged from the filter. The relationships between antibacterial activity (minimum inhibition concentration, MIC; minimum lethal concentration, MLC) and structural parameters of the QACs (head group size and alkyl chain length) are discussed. The antibacterial activity of QACs in aqueous phases is mainly due to the free monomeric species. Bacterial inactivation is enhanced by QACs with longer alkyl chains. In most recorded cases, however, minimum MIC and MLC values occurred at n = 14–16 and mostly at n = 16, where n is the number of C atoms in the alkyl chain. This outcome is explained by the combination of two antagonistic effects: (i) An increase in alkyl chain length (i.e., QAC hydrophobicity) enhances QAC binding, penetration, and destabilization of bacterial membranes; and (ii) an increase in alkyl chain length lowers the critical micelle concentration (CMC) of QACs and, thus, reduces QAC monomer concentrations, which more efficiently inactivate bacteria than the micelles. The octadecyltrimethylammonium (ODTMA, n = 18) MLC value (0.25 μm) for the cyanobacterium genus Aphanizomenon is significantly lower than the CMC (300 mm) value. Hence, a test to determine the minimum MLC value at n = 16 is of interest. Removal of bacteria from water by filtration is expected to be made more efficient by small increases in the ODTMA/clay ratio in the complex, which will act to increase the concentrations of ODTMA cations released during filtration.

Fluoride is an essential component in the mineralization of bones and in the formation of dental enamel. Excessive intake may result, however, in teeth mottling and dental and skeletal fluorosis. With an average fluoride concentration of ~2.4 mg L−1 in Tunisian drinking water, the present study focused on promoting low-cost materials for removal of excess fluoride. Two Tunisian raw clays were used as adsorbents in a batch process to eliminate excess fluoride ions from drinking water and, thus, avoid fluorosis phenomena. Physicochemical characterization and chemical analysis of the raw clays were carried out using X-ray fluorescence, X-ray diffraction, and the BET method. For fluoride removal, the effects of contact time, adsorbent dose, and pH were evaluated. The optimum defluoridation capacity was at 30 min of contact time, 20 g/L of clay dose, and at pH = 3. The kaolinite tested removed more fluoride than smectite. The selected clay was used successfully to remove fluoride from contaminated water with high concentrations of foreign ions that exceeded the potability limits. Adsorption isotherms revealed that the data fitted well to both the Langmuir and Freundlich adsorption isotherms, thus confirming both monolayer and multilayer adsorption.

Developing low cost and effective phosphate adsorbents is crucial to prevent eutrophication of natural waters. Here, phosphate removal by a natural and abundant shale from the Ivory Coast was investigated in both batch and column experiments with special attention devoted to understand the adsorption process. Batch experiments were carried out to assess the influence of initial phosphate concentration, sorbent dosage, contact time, and pH on phosphate removal. The phosphate removal efficiency increased with increased shale dosage while phosphate uptake decreased. Aqueous Ca, Mg, Al, and Fe species concentrations decreased in the presence of phosphate. Additionally, phosphate uptake strongly decreased with pH increases in the range 2–11, but then increased at pH 12. The kinetics were well described using a pseudo-second order model, and Langmuir adsorption isotherms were used for the equilibrium surface reactions. Adsorption to nanoparticles of goethite was hypothesized to be the major phosphate removal mechanism in the pH range 4–10. Column experiments with a flow rate of 1 mL min−1 and an initial phosphate concentration of 25 mg L−1 showed a breakthrough point at a V/Vp value of ~17, where Vis the volume of phosphate solution added to the column and Vp is the pore volume. A V/Vp value of ~17 corresponded to a phosphate uptake of 0.17 mg/g, which was in agreement with the batch experiments. Column experiments revealed a strong correlation between the aqueous concentrations of Ca, Mg, Al, and Fe species and phosphate removal and, thus, suggest that phosphate removal by the shale occurred by aqueous dissolution/precipitation.

Toxic pollutants such as diclofenac (DCF) and cadmium(II) have been detected together in various water sources; these compounds have adverse effects on human health. The objective of the present study was to investigate the sorption of DCF and Cd(II) from aqueous solutions on an organobentonite. The organobentonite was synthesized by adsorbing the surfactant hexadecyltrimethylammonium (HDTMA) on bentonite; this was designated OBHDTMA. The sorption of DCF and Cd(II) on OBHDTMA and of Cd(II) on OBHDTMA saturated with DCF (OBHDTMA-DCF) were then studied. The bentonite, OBHDTMA, and OBHDTMA-DCF were characterized by X-ray diffraction, thermogravimetric analysis, and Fourier-transform infrared spectroscopy. The capacity of OBHDTMA for adsorbing DCF depended on the solution pH, ionic strength, and temperature. The effect of pH on the adsorption capacity of OBHDTMA was anomalous because, depending on the concentration of DCF at equilibrium, the adsorption capacity increased or decreased by raising the pH. The capacity of OBHDTMA was enhanced by increasing the temperature from 15 to 35°C and by reducing the ionic strength from 1 to 0.01 N. The dependence of the adsorption capacity on the operating conditions was explained by considering the interactions between the DCF in solution and the surface of OBHDTMA. The maximum sorption capacity of the OBHDTMA for DCF was 388 mg/g at T = 25°C and at pH = 7 and was comparable to those of carbon materials. The adsorption of DCF on OBHDTMA was scarcely reversible, but the desorption percentage increased with pH. The adsorption of DCF on OBHDTMA was due to partition and electrostatic attraction. More Cd(II) was adsorbed on OBHDTMA-DCF than on OBHDTMA and this was influenced by the loading of DCF on the OBHDTMA-DCF. The OBHDTMA-DCF may be used to remove Cd(II) from water solution.