Improvement of biochar capability in Cr immobilization via modification with chitosan and hematite and inoculation with Pseudomonas putida     

Zahra Zibaei  Abdolmajid Ronaghi  Mehdi Zarei  Sedigheh Zeinali 《Communications in Soil Science and Plant Analysis》2020,51(7):963-975

ABSTRACT

Modification of biochar using chitosan and hematite made the biochar product more effective for hexavalent chromium (Cr (VI)) reduction in contaminated soils. Release experiment was conducted to examine Cr (VI) reduction in different treatments (control, unmodified biochar and two modified biochars with chitosan or hematite). The results indicated that the application of all treatments significantly decreased the release rate of Cr in comparison to the control treatment. Chitosan-modified biochar application increased Cr (VI) reduction from 28.53% (biochar) to 46.23%. In the case of hematite-modified biochar, it increased Cr (VI) reduction from 28.55% (biochar) to 38.95%. Two kinetic equations including pseudo-first-order and pseudo-second-order models employed to describe the time-dependent Cr release data. Between the kinetic equations estimated, the pseudo-second order best fitted to experimental data. In the presence of Pseudomonas putida, cumulative Cr release rate decreased by 2.38 mg kg^?1 (50.29%) in hematite–biochar and 1.768 mg kg^?1 (39.73%) in unmodified biochar as compared with control (4.43 mg kg^?1). According to results reported herein, modification of biochar with chitosan or hematite is promising since made biochar more effective in removing Cr from Cr-polluted calcareous soils.  相似文献   

Fabrication of hollow nanofibrous structures using a triple layering method for vascular scaffold applications     

Seyedeh Nooshin Banitaba  Golchehr Amini  Ali Akbar Gharehaghaji  Ali Asghar Asgharian Jeddi 《Fibers and Polymers》2017,18(12):2342-2348

This study aims to develop a new approach for fabricating hollow nanofibrous yarns by engineering a triple-layer structure (polyvinyl alcohol (PVA) multifilament core surrounded by a layer of PVA nanofibers and a polylactic acid (PLA) nanofiber outer layer). After fabrication of this 3-layer structure, the core portion was extracted, leaving the outer layer intact after dissolving the PVA nanofibers in water. To determine the optimum thickness of the outer layer, hollow nanofiber yarns with five different thicknesses were produced. A hollow nanofiber yarn was also produced using a common method to enable comparison of the methods. In the common method, a core sheath yarn consisting of a PVA multifilament core and a PLA nanofiber outer layer was fabricated, and a hollow yarn was produced by placing the core yarn in hot water. The results revealed facilitation of core extraction from the yarn body of the new 3-layer structure, which occurred due to rapid dissolution of the middle layer. The wicking behavior in the hollow yarn fabricated using the novel method followed the Locus Washburn equation and that of the hollow yarn produced from the core sheath yarn deviated from it. The results demonstrated that tensile properties of hollow nanofiber yarns were improved by increasing the thickness. Furthermore, hemolysis and cytotoxicity assays indicated that the fabricated hollow nanofibrous structure is non-toxic and blood compatible, indicating its potential for use in biomedical applications such as vascular scaffolds.  相似文献   

Effects of desert dust on yield and yield components of cowpea (Vigna unguiculata L.)     

Zahra Hatami  Alireza Rashki  Mehdi Nasiri Mahallati  Behnam Habibi Khaniani 《Archives of Agronomy and Soil Science》2018,64(10):1446-1458

In order to study the effects of desert dust on yield and yield components of cowpea, two field experiments were conducted in the factorial layout based on randomized complete block design with three replicates in Dezful and Mashhad, Iran in 2015. The experimental treatments were combinations of desert dust in three levels (0, 500 and 1500 µg m^?3), numbers of desert dust application (once, twice and thrice) and two types of desert dust. The desert-dust particles were collected during dust storms occurred in Dezful and Zabol, which are the main sources of dust in Iran. The results showed that the biological yield and the grain yield were significantly decreased in both studied sites (Dezful and Mashhad) when the plants exposed to 500 µg m^?3 desert dust treatment compared to normal conditions. Total soluble sugar and proline contents in plant leaf tissues increased significantly when they affected by 1500 µg m^?3 of desert dust, while the plant height was significantly decreased by increasing the desert-dust concentrations at both sites. Biological yield, grain yield, and 100-seed weight were also significantly affected by the desert dust. Overall, the desert dust has adverse effects on yield of cowpea.  相似文献   

Quality and elemental content of citrus fruit from exposed and internal canopy positions 1     

Esmaeil Fallahi  John W. Moon Jr.  Zahra Mousavi 《Journal of plant nutrition》2013,36(8):939-951

Quality and elemental content of fruit from internal tree canopies were compared with those from external canopy positions in 4 citrus varieties: ‘Kinnow’ mandarin; ‘Redblush’ grapefruit; ‘Valencia’ orange; and ‘Lisbon’ lemon. Fruit weight, total juice per fruit, peel fresh and dry weight, and rind thickness of fruit from internal canopies of all 4 varieties were significantly higher compared with external fruit. Mandarin, grapefruit, and orange fruit from external canopies had higher soluble solids and specific gravity. Fruit from internal canopies of all varieties had generally higher peel concentrations (% dry weight) of N, P and K due to a dilution effect, while the opposite condition existed in mandarin when these elements were expressed on a percent fresh weight basis. Peel Mg and S from external fruit were higher in all varieties, expressed as percentages of either dry weight or fresh weight. Nitrogen content of mandarin and orange juice and Ca content of grapefruit and lemon juice from external fruit were significantly higher compared to those from internal canopy fruit. Elimination of fruit quality and mineral variations as a result of canopy positions is recommended by the means of cultural practices.  相似文献   

Comparative study on hormones and biochemistry indices in plasma,ovarian fluid and oocytes of LHRHa2‐induced female Stellate sturgeon (Acipenser stellatus)     

Zahra Roosta  Sareh Ghiasi  Bahram Falahatkar 《Aquaculture Research》2019,50(1):139-145

Reproduction efficacy of sturgeon as donors of oocytes is regulated by hormones effects. It can influence the egg quality or larvae functions as rearing mediators for successful production. This study is conducted to evaluate the concentration of sex steroids, cortisol and thyroid hormones and distinguish the relationship of maternal hormones' correlation in Stellate sturgeon. The study followed the hormones fluctuations that could impress some egg quality information such as fertilization rate. Female breeders were injected with LHRH_a2 for controlled propagation. Samples from blood, ovarian fluid and oocytes were obtained for hormonal and biochemical analysis. Our results showed that the concentrations of estradiol 17‐β and testosterone were significantly higher and lower in oocyte and the plasma, respectively. The level of plasma cortisol was significantly higher than in ovarian fluid and oocytes. The results showed elevation of triiodothyronine and thyroxine concentrations in oocytes, which were significantly different with plasma and ovarian fluid. Thyroxine concentration of plasma and ovarian fluid revealed a significant negative correlation. The mentioned parameters showed negative correlation with fertilization rate. The biochemical parameters (calcium, glucose, cholesterol and triglyceride) revealed significant differences in blood, ovarian fluid and oocytes. These results showed direct relations of fertilization rate with hormones level. Therefore, fertilization rate as egg quality index could be recommended as a relevant indicator of maternal transferring of hormones from blood and ovarian fluid to oocyte.  相似文献