Effect of pre-treatment of bentonite with sodium and calcium ions on phosphate adsorption onto zirconium-modified bentonite.

To understand the influence of the pre-treatment of bentonite with Na+ and Ca2+ on the adsorption of phosphate on zirconium-modified bentonite, three kinds of adsorbent materials including zirconium-modified raw, Na+-pretreated and Ca2+-pretreated bentonites were synthesized and characterized firstly, and afterward their adsorption performance and mechanism for phosphate were studied comparatively. The phosphate adsorption ability for zirconium-modified bentonite decreased after the pre-treatment of bentonite with Na+, but it increased after the pre-treatment of bentonite with Ca2+. The maximum phosphate adsorption capacity calculated from the Langmuir isotherm model for zirconium-modified Ca2+-pretreated bentonites (13.4 mg P/g) was much higher than that for the zirconium-modified raw bentonite (9.06 mg P/g). The pre-treatment of bentonite with Na+ and Ca2+ did not change the interaction type between zirconium-modified bentonite and phosphate, i.e., the coordination of phosphate to zirconium. The decreased phosphate adsorption capacity for zirconium-modified bentonite induced by the Na+ pre-treatment could be mainly attributed to the decrease of the specific surface area and the content of exchangeable Ca. The increased phosphate adsorption capacity for zirconium-modified bentonite induced by the Ca2+ pre-treatment could be mainly due to the increase in the amount of exchangeable Ca. Results of this work suggest that the zirconium-modified Ca2+-pretreated bentonite is more suitably used as an adsorbent for the removal of phosphate from wastewater than the zirconium-modified raw and Na+-pretreated bentonites.

Construction of chub mackerel (Scomber japonicus) fishing ground prediction model in the northwestern Pacific Ocean based on deep learning and marine environmental variables.

Accurate prediction of the central fishing grounds of chub mackerel is substantial for assessing and managing marine fishery resources. Based on the high-seas chub mackerel fishery statistics and multi-factor ocean remote-sensing environmental data in the Northwest Pacific Ocean from 2014 to 2021, this article applied the gravity center of the fishing grounds, 2DCNN, and 3DCNN models to analyze the spatial and temporal variability of the chub mackerel catches and fishing grounds. Results:1) the primary fishing season of chub mackerel fishery was April-November which catches were mainly concentrated in 39°âˆ¼43°N, 149°âˆ¼154°E. 2) Since 2019, the annual gravity center of the fishing grounds has continued to move northeastward; the monthly gravity center has prominent seasonal migratory characteristics. 3) 3DCNN model was better than the 2DCNN model. 4) For 3DCNN, the model prioritized learning information on the most easily distinguishable ocean remote-sensing environmental variables in different classifications.

[Influence of Calcium Ion Pre-treatment on Phosphate Adsorption onto Magnetic Zirconium/Iron-modified Bentonite].

Two kinds of magnetic zirconium/iron-modified bentonites (ZrFeBTs), including magnetic zirconium/iron modified raw bentonite (ZrFeRBT) and magnetic zirconium/iron-modified Ca2+-pretreated bentonite, (ZrFeCaBT) were prepared and characterized. Their phosphate adsorption characteristics were compared to determine the effect of the Ca2+ pre-treatment on the adsorption of phosphate onto ZrFeBTs. The results showed that the as-prepared ZrFeBTs contained Fe3O4 and Zr, and the content of exchangeable Ca2+ in ZrFeCaBT was much higher than that in ZrFeRBT. The adsorption isotherm data exhibited good agreement with the Langmuir isotherm model, with maximum monolayer phosphate adsorption capacities of 8.70 mg·g-1 and 11.5 mg·g-1 for ZrFeRBT and ZrFeCaBT, respectively. The isotherm and kinetics studies showed that the adsorption of phosphate on ZrFeBTs was a chemisorption process. The phosphate adsorption capacities for ZrFeBTs decreased with increasing solution pH. The ZrFeBTs exhibited a high selective adsorption for phosphate in the presence of anions and cations, including Cl-, HCO3-, SO42-, NO3-, Na+, K+, Mg2+, and Ca2+. Furthermore, coexisting Ca2+ greatly enhanced the adsorption of phosphate onto ZrFeBTs. The pre-treatment of raw bentonite with Ca2+ significantly improved the adsorption of phosphate onto ZrFeBTs.

Growing pigs developed different types of diabetes induced by streptozotocin depending on their transcription factor 7-like 2 gene polymorphisms.

The different polymorphisms of the transcription factor 7-like 2 (TCF7L2) gene promote variances in diabetes susceptibility in humans. We investigated whether these genotypes also promote differences in diabetic susceptibility in commercial pigs. Growing pigs (Landrace, both sex, 50-60 kg) with the C/C (n=4) and T/T (n=5) TCF7L2 genotypes were identified and intravenously injected with streptozotocin (STZ, 40 mg/kg) twice in weekly intervals, then a high-energy diet was offered. Oral glucose tolerance tests, blood analyses and the homeostasis model assessment-insulin resistance (HOMA-IR) index calculations were performed. The animals were sacrificed at the end of 12 weeks of treatment to reveal the pancreas histomorphometry. The results showed that all of the treated pigs grew normally despite exhibiting hyperglycemia at two weeks after the induction. The glycemic level of the fasting or postprandial pigs gradually returned to normal. The fasting insulin concentration was significantly decreased for the T/T carriers but not for the C/C carriers, and the resulting HOMA-IR index was significantly increased for the C/C genotype, indicating that the models of insulin dependence and resistance were respectively developed by T/T and C/C carriers. The histopathological results illustrated a significant reduction in the pancreas mass and insulin active sites, which suggested increased damage. The results obtained here could not be compared with previous studies because the TCF7L2 background has not been reported. Growing pigs may be an excellent model for diabetic in children if the animals are genetically pre-selected.

[Adsorption of Phosphate from Aqueous Solution on Hydrous Zirconium Oxides Precipitated at Different pH Values].

In this study, hydrous zirconium oxide (HZO) samples precipitated at different pH values were prepared, characterized and used as adsorbents to remove phosphate from aqueous solution. The adsorption characteristics and mechanisms of phosphate on these HZO samples were investigated. The results showed that the presence of Na+ slightly enhanced the adsorption of phosphate on HZO samples prepared at precipitation pH of 4.8 and 8.0, but it greatly enhanced the adsorption of phosphate on HZO prepared at precipitation pH of 10.6. The presence of Ca2+ slightly enhanced the adsorption of phosphate on HZO prepared at precipitation pH of 4.8, but it significantly enhanced the adsorption of phosphate on HZO samples prepared at precipitation pH of 8.0 and 10.6. The presence of HCO3- or SO42- inhibited phosphate adsorption onto HZO, and the inhibitory effect of these anions on phosphate adsorption onto HZO precipitated at pH 4.8 was much higher than that on phosphate adsorption onto HZO samples precipitated at pH 8.0 and 10.6. The phosphate adsorption was dependent upon solution pH, and it decreased with increasing solution pH. The Langmuir, Freundlich and Dubinin-Redushckevich (D-R) isotherm models fitted well to the adsorption equilibrium data of phosphate on HZO samples precipitated at pH 4.8, 8.0 and 10.6. In the presence of Na+ but in the absence of Ca2+, there was no significant difference of the maximum phosphate monolayer adsorption capacity derived from the Langmuir isotherm model among HZO samples prepared at precipitation pH of 4.8, 8.0 and 10.6. In the presence of Ca2+, the maximum phosphate monolayer adsorption capacity derived from the Langmuir isotherm model for HZO precipitated at pH 8.0 or 10.6 was much higher than that for HZO precipitated at pH 4.8. The mechanism for phosphate adsorption onto HZO mainly obeyed the inner-sphere complexing mechanism. The surface chloride and hydroxyl groups played the key role in the adsorption of phosphate on HZO precipitated at pH 4.8 or 8.0, while only the surface hydroxyl groups played the key role in the adsorption of phosphate on HZO precipitated at pH 10.6. Results of this work demonstrated that the HZO precipitated at pH 8.0 or 10.6 was a more promising adsorbent for removing phosphate from wastewater than the HZO precipitated at pH 4.8.