Search

The floc solid waste (FSW) significantly increased the soil fertility.

Separation of rare earth elements has always been an urgent problem in the industry. Although a variety of adsorption materials have been developed for the adsorption and separation of rare earth elements, it is difficult to achieve high adsorption capacity and high separation selectivity from most of them at the same time. In this work, to combine the advantages of the good adsorption capacity of graphene oxide (GO) and high separation selectivity of metal organic frameworks (MOFs), two-dimensional MOFs and GO nanocomposite materials (2D Zn-BDC MOF/GO) were synthesized by a solvothermal interlayer-confined strategy. The composite material has a maximum adsorption capacity of 344.48 mg/g for rare earth ions, with the selectivity of Sc/Tm ≈ 529.57, Sc/Er ≈ 461.91, Sc/Y ≈ 445.70, and Tm/Eu ≈ 4.55. This work brings us a new route to synthesize 2D MOF/GO nanocomposite materials and combine their advantages for the separation of rare earth elements in chemical engineering research.

Design and construction of a membrane that can achieve selective separation of uranium from spent fuel or seawater is a big challenge in the field of separation science. In this work, 1,3,5-benzenetricarboxylic acid (BTC) and three different nitrates (Zn/Ni/Cu) were used to prepare metal–organic frameworks (BTC–MOFs) with different pore sizes, and then, BTC–MOFs were intercalated into the interlayers of graphene oxide (GO) for preparing the composite membranes which presented selective separation of uranium with strong acid resistance. Composite membranes prepared by Zn/Ni/Cu-BTC–MOFs and GO can achieve the separation between ions of different valence states, and their permeability and selectivity depend on the membrane thickness, the acidity of driving solution, and the pore sizes of MOFs. Importantly, Cu-BTC–MOF-intercalated GO membranes can not only achieve the selective separation of Th4+and UO22+with a selectivity of ≈6 but also induce the ultra-high selectively separation of UO22+and Ce3+because the rejection rate of Ce3+is about 100%. Moreover, the Zn-BTC–MOF-intercalated GO membrane shows an excellent selectivity of Th4+and UO22+with a selectivity of ≈25, and it may also achieve selective separation of uranium from seawater.

Rare earth elements (REEs) are used widely in devices of many fields, but it is still a troublesome task to achieve their selective separation and purification. Metal–organic frameworks (MOFs) as an emerging porous crystalline material have been used for selective separation of REEs using the size-selective crystallization properties. However, so far, almost all MOFs cannot be used directly for selective separation of REEs in strong acid viasolid-state adsorption. Herein, a zinc-trimesic acid (Zn-BTC) MOF is grown by solid synthesis in situon ZnO nanoparticles covering nanoporous graphene for preparing Zn-BTC MOF/nanoporous graphene composites with strong acid resistance. The adsorption capacity of the resulting composites to REEs is highly sensitive to the ionic radius, which may be attributed to the fact that the REE ions coordinate with O to form a stable structure. The selectivity of Ce/Lu is ≈10,000, and it is extremely important that the selectivity between adjacent REEs (e.g., Nd/Pr) is as high as ≈9.8, so the composite exhibits the best separation performance so far. This work provides a green, facile, scale, and effective synthesis strategy of Zn-BTC MOF/nanoporous graphene, which is hopefully applied directly in the separation industries of REEs.

Chiral materials are usually the key to the separation of chiral membranes. In this work, we propose a new strategy that chiral porous graphene membrane can be fabricated from nonchiral porous graphene by mechanical stirring to induce vortex structure. Porous graphene with controlled, nanosized pores was synthesized by a newly designed, one-pot process directly from graphite as opposed to graphene oxide. Then porous graphene was immobilized on ultrafiltration membrane through filtering while stirring to form porous graphene membrane, which was applied for enantioselective separation toward DL-amino acids: for example, the separation factor of l-/d-phenylalanine reached 4.76. Interestingly, we first observed that the front and back sides of the porous graphene membrane exhibited opposite optical activities.

In this study, a pilot-scale fixed-film denitrification bio filter was developed using polycaprolactone (PCL) as a carbon source and biofilm carrier to remove nitrate-nitrogen (NO–3–N) from the water of a recirculating aquaculture system. As the hydraulic retention time (HRT) increased from 2 to 8 h, NO–3–N removal efficiencies increased from 5 to 65%. The highest removal rate of 1.11 ± 0.34 kg NO–3–N/m3·d was achieved at an HRT = 8 h with a flow rate of 0.71 L/m3·h. Unused dissolved organic carbon (DOC) from PCL degradation for all HRT amounted to less than 10 mg/L, and this value increased with increasing HRT. Observations of the PCL surface indicated that chain scission by hydrolytic degradation and biological utilisation in the reactors did not significantly change its chemical structure. Microbial community analysis showed the predominance of Proteo bacteria and Bacteroidetes in the bio film, with relative abundances of 63.9% and 27.4%, respectively. Six genera namely Acidovorax, Azospira, Comamonas, Diaphorobacter, Ignavibacterium, and Frateuria, could both degrade PCL and denitrify NO–3–N.

This aim of this study was to investigate the effects of dietary aucubin on the growth, flesh quality, and metabolomics of grass carp (Ctenopharyngodon idella). Five diets were designed with the aucubin inclusion of 0 (control diet), 0.2, 0.4, 0.6, and 0.8 g/kg (Auc-0.2, Auc-0.4, Auc-0.6, Auc-0.8) and were fed to grass carp with an initial body weight of 17.0 ± 0.2 g for 60 d. The results indicated that dietary aucubin did not significantly affect the growth performance of grass carp (P> 0.05). Compared to the control, dietary supplementation with 0.2 to 0.8 g/kg aucubin increased flesh hardness, chewiness, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and the contents of total free amino acids (TFAA) and n-3 polyunsaturated fatty acids (n-3 PUFA) (P< 0.05). The contents of malondialdehyde (MDA) and lactic acid (LD) in the flesh were significantly decreased by the addition of 0.4 to 0.6 g/kg aucubin and by the addition of 0.6 to 0.8 g/kg aucubin (P< 0.05), respectively, while the content of delicious amino acids (DAA) was significantly enhanced by the addition of 0.4 to 0.8 g/kg aucubin (P< 0.05). Moreover, the contents of collagen and C22:6n3 (DHA) in the flesh of the Auc-0.8 group were significantly higher than those of the control (P< 0.05). In the metabolomics profiling of flesh, 133 and 135 named differential metabolites were identified in the Auc-0.4 and Auc-0.8 groups, respectively, compared to the control, and these metabolites were found to be involved in the second-grade pathways of “lipid metabolism” and “amino acid metabolism”. Regarding gene expression, the mRNA levels of CuZn-SOD, CAT, COL1A1, COL1A2, Smad4, and FASin flesh were upregulated in the Auc-0.4 and Auc-0.8 groups, and the expression levels of GPx, Nrf2, and TGF-β1mRNA were also upregulated in the Auc-0.8 group (P< 0.05). In summary, dietary aucubin did not promote growth, but improved the flesh quality of grass carp, which might be associated with the TGF-β/Smadand Nrf2pathways. The recommended supplementation level of aucubin in the diet of grass carp was 0.6 to 0.8 g/kg.Dietary aucubin did not affect the growth of grass carp, but improved the flesh quality of grass carp through the TGF-β/Smadand Nrf2pathways.Aucubin is an iridoid glycoside that is widely distributed in green plants and exhibits various biological activities such as antioxidant, anti-inflammatory, and protecting the liver. In previous studies, we explored the effects of different dietary levels of iridoids including geniposide and geniposide acid, on the flesh quality of grass carp. As aucubin shares a similar chemical structure to that of geniposide and geniposide acid, it was speculated that aucubin might exhibit the same function of promoting flesh quality in fish. Our study was conducted to explore the effects on the growth and flesh quality of grass carp. We found that dietary aucubin did not affect the growth of grass carp but improved flesh quality by increasing the contents of collagen, free amino acids, and n-3 PUFA; increasing the activities of CAT, SOD, and GPx; and decreasing the contents of MDA and PC in flesh, which might be associated with the TGF-β/Smadand Nrf2pathways.

The jade perch Scortum barcoois a new species in the developing freshwater finfish grow-out sector. In this study, the effects of salinity (0, 5, and 10‰) on growth and several physiological indicators of jade perch were investigated. Salinity did not have a significant effect on mean weight gained, condition factor, and feed efficiency of the fish, but it significantly affected their specific growth rate during the 28-d experiment. The levels of serum alanine transaminase and triacylglycerol did not differ significantly among the three treatment groups, but salinity did significantly affect serum cortisol level and serum lysozyme activity. Despite the elevation in circulating cortisol induced by saline conditions, growth of jade perch was not negatively affected, and the specific growth rate suggested an improved growth rate in fish held in 5‰ salinity water.

AbstractThe jade perch Scortum barcoois a new species in the developing freshwater finfish grow-out sector. In this study, the effects of salinity (0, 5, and 10‰) on growth and several physiological indicators of jade perch were investigated. Salinity did not have a significant effect on mean weight gained, condition factor, and feed efficiency of the fish, but it significantly affected their specific growth rate during the 28-d experiment. The levels of serum alanine transaminase and triacylglycerol did not differ significantly among the three treatment groups, but salinity did significantly affect serum cortisol level and serum lysozyme activity. Despite the elevation in circulating cortisol induced by saline conditions, growth of jade perch was not negatively affected, and the specific growth rate suggested an improved growth rate in fish held in 5‰ salinity water.Received May 31, 2011; accepted December 5, 2011