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Influence of Solvent onto chemical extraction of America-Type Coconut (Coco nucifera L.) Fbers: Analysis of Physicochemical, Mechanical and Morphological Properties

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Journal of Textile Science and Technology 2024年第3期10卷 64-81页

作者： Delphine Korgai Gandai Zara Haman Djoda Pagore Frederic Memtine Ndong Augustin Abdourhamane Nsangou Niraka Blaise Hambate Gomdje Valery National Advanced School of Engineering of Maroua University of Maroua Maroua Cameroon School of chemical Engineering and Mineral Industries University of Ngaoundere Ngaoundere Cameroon Department of Mechanical Engineering ENSET University of Douala Douala Cameroon

In this study, the natural fibers from Coconuts of the species Coco nucifera L. were chemically extracted in different solvents such as sodium hydroxide (SH), acetone (AC) and sodium hydroxide-acetone (SHA) for their applications in the textile industries. Structural, morphological and physico-mechanical characterizations such as X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanned electron microscopy (SEM), measurements of density, Young’s modulus, water absorption rate and humidity were evaluated. The XRD and FTIR results show that Coco nucifera L. fibers contains type I cellulose. Mechanical characterizations were also carried out. These results show that by varying the different solvents used, the physico-chemical, mechanical and morphological properties of the fibers change, which implies that the solvent has an influence on the properties of these fibers. The fibers extracted by the sodium hydroxide-acetone mixture have a linear density of 1.636, the percentage of water absorption is 62.428%, the percentage of moisture absorption 9.605% compared to other values in the literature shows that this solvent mixture improves the properties of coconut fibers which contain type I cellulose. The tensile stress is 0.013 GPa, the percentage strain is 49.836% and the Young’s modulus is 0.114 GPa as well as the percentage elongation show that these fibers are elasto-plastic. The values obtained mean that these fibers are suitable for use in textiles.

关键词： chemical extraction Cellulose Coco nucifera L. Fibers Elasto-Plastic Textiles

Arsenic removal from contaminated soil using phosphoric acid and phosphate

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Journal of Environmental Sciences 2008年第1期20卷 75-79页

作者： ZENG Min LIAO Bohan LEI Ming ZHANG Yong ZENG Qingru OUYANG Bin College of Resources and Environment Central South University of Forestry and Technology Changsha 410004 China. College of Biological Science and Technology Hunan Agricultural University Changsha 410128 China International College Central South University of Forestry and Technology Changsha 410004 China

Laboratory batch experiments were conducted to study arsenic （As） removal from a naturally contaminated soil using phosphoric acid （H3PO4） and potassium dihydrogen phosphate （KHEPO4）. Both H3PO4 and KHEPO4 proved to reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L. At the same time, acidification of soil and dissolution of soil components （Ca, Mg, and Si） resulted from using these two extractants, especially H3PO4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions （PO4^3-）. The function of H3PO4 as an acid to dissolve soil components had little effects on As removal. KH2PO4 almost removed as much As as H3PO4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 rain, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich model best described the kinetic data of As removal among the four models used in the kinetic study.

关键词： arsenic (As) removal phosphoric acid (H3PO4), potassium dihydrogen phosphate (KH2PO4) chemical extraction

Tissue-engineered rhesus monkey nerve grafts for the repair of long ulnar nerve defects:similar outcomes to autologous nerve grafts

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Neural Regeneration Research 2016年第11期11卷 1845-1850页

作者： Chang-qing Jiang Jun Hu Jian-ping Xiang Jia-kai Zhu Xiao-lin Liu Peng Luo Department of Sports Medicine and Rehabilitation Peking Universtiy Shenzhen Hospital Shenzhen Guangdong Province China Department of Microscopy First Affiliated Hospital of Sun Yat-sen University Guangzhou Guangdong Province China The Sixth People's Hospital of Shenzhen City Shenzhen Guangdong Province China

Acellular nerve allografts can help preserve normal nerve structure and extracellular matrix composition. These allografts have low immunogenicity and are more readily available than autologous nerves for the repair of long-segment peripheral nerve defects. In this study, we repaired a 40-mm ulnar nerve defect in rhesus monkeys with tissue-engineered peripheral nerve, and compared the outcome with that of autograft. The graft was prepared using a chemical extract from adult rhesus monkeys and seeded with allogeneic Schwann cells. Pathomo- rphology, electromyogram and immunohistochemistry findings revealed the absence of palmar erosion or ulcers, and that the morphology and elasticity of the hypothenar eminence were normal 5 months postoperatively. There were no significant differences in the mean peak compound muscle action potential, the mean nerve conduction velocity, or the number of neurofilaments between the experimental and control groups. However, outcome was significantly better in the experimental group than in the blank group. These findings suggest that chemically extracted allogeneic nerve seeded with autologous Schwann cells can repair 40-mm ulnar nerve defects in the rhesus monkey. The outcomes are similar to those obtained with autologous nerve graft.

关键词： nerve regeneration peripheral nerve injury tissue engineering rhesus monkey ulnar nerve chemical extraction allogenic nerve autologous nerve transplantation Schwann cells neural regeneration

Prediction of Polycyclic Aromatic Hydrocarbon Bioaccessibility to Earthworms in Spiked Soils by Composite extraction with Hydroxypropyl-β-Cyclodextrin and Organic Acids

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Pedosphere 2017年第3期27卷 502-510页

作者： ZHANG Yanan YANG Xinglun GU Chenggang BIAN Yongrong LIU Zongtang JIA Mingyun WANG Fang WANG Daizhang JIANG Xin Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science Chinese Academy of Sciences University of Chinese Academy of Sciences College of Resources and Environment Henan Agricultural University

Traditional exhaustive extraction methods often overestimate the risk of polycyclic aromatic hydrocarbon(PAH) bioaccessibility to biota. Therefore, reliable assessment methods need to be established. In this study, a composite extraction with hydroxypropyl-β-cyclodextrin(HPCD) and three low-molecular-weight organic acids, oxalic acid(OA), malic acid(MA), and citric acid(CA), was used to predict the PAH bioaccessibility to earthworms, subjecting to two soils(red soil and yellow soil) spiked with selected PAHs,phenanthrene, pyrene, chrysene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene. For both soils,concentrations of PAHs by composite extraction using HPCD-OA(R^2= 0.89–0.92, slope = 1.89–2.03; n = 35), HPCD-MA(R^2=0.92–0.96, slope = 1.43–1.67; n = 35), and HPCD-CA(R^2= 0.92–0.96, slope = 1.26–1.56; n = 35) were significantly correlated with PAH accumulation in the Eisenia fetida earthworms. Moreover, the HPCD-CA-and HPCD-MA-extracted PAH concentrations were closer to the earthworm-accumulated PAH concentration than the extraction using just HPCD. The results indicated that the composite extraction could improve the prediction of PAH bioaccessibility, and therefore can serve as a reliable chemical method to predict PAH bioaccessibility to earthworms in contaminated soils.

关键词： chemical extraction citric acid earthworm accumulation low-molecular-weight organic acid malic acid

TiO2 nanoparticles in aquatic environments:impact on heavy metals distribution in sediments and overlying water

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Acta Geochimica 2022年第6期41卷 968-981页

作者： Ali Marefat Abdolreza Karbassi Behzad Aghabarari School of Environment College of EngineeringUniversity of TehranTehranIran Research Department of Nano-technology and Advanced Materials TehranIran

The extensive application of TiO_(2)nanoparticles(NPs)highlights the importance of investigating their influence on aquatic *** this work,the effect of TiO_(2)NPs on heavy metals speciation was studied on a lab *** this goal,a series of aquaria containing water,sediment,and TiO_(2)NPs with various concentrations were set *** study results revealed that TiO_(2)NPs caused(copper)Cu,(mercury)Hg,(titanium)Ti,and(zinc)Zn to be adsorbed by sediments in the forms of exchangeable and Fe-Mn *** to measurements,30μg/L of TiO_(2)NPs made Cu,Hg,Ti and Zn concentration in the water column decreased from 33,1.14,20,and 32 to 4,0.58,3,and 22.3μg/L,***(Mn)was also adsorbed by sediment,and in all experiments,its concentration in the water column reduced from 44 to about 20μg/*** to the photocatalytic capacity of TiO_(2)NPs,arsenic(As)concentration in the water column increased from 0 to 8.7μg/L with the introduction of30μg/L of TiO_(2)*** sequential extraction results showed that in all experiments,concentrations of lead(Pb),nickel(Ni),and cobalt(Co)remained constant in different chemical species of sediment,which meant conservative behavior of them in presence of TiO_(2)*** addition,a remarkable change was observed in water quality parameters such as ORP,TDS,TOC,BOD,NO3’and PO_(4)after the introduction of TiO_(2)NPs to *** reason behind these changes could be related to the decomposition of sediment organic content by TiO_(2)NPs.

关键词： TiO2 nanoparticles Heavy metal speciation Redox potential chemical extraction Cluster analysis

Application of Kinetic Models in Describing Soil Potassium Release Characteristics and Their Correlations with Potassium Extracted by chemical Methods

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Pedosphere 2013年第4期23卷 482-492页

作者： A. R. HOSSEINPUR H. R. MOTAGHIAN Department of Soil Science College of Agriculture Shahrekord University

Potassium （K） release characteristics in soil play a significant role in supplying available K. Information on K-release characteristics in soils of central Iran is limited. The objectives of this study were to determine K release characteristics and correlations of K release rate constants with K extracted by different chemical methods in surface soils of ten calcareous soils of central Iran. The kinetics of K release in the soils was determined by successive extraction with 0.01 mol L-1 CaC12 in a period of 2-2017 h at 25±1℃. Soil K was extracted by distilled water, 0.5 mol L-1 MgNO3, 0.002 mol L-1 SrC12, 0.1 mol L-1 BaC12, 0.01 mol L-1 CaC12, 1 mol L-1 NaC1, 1 mol L-1 boiling HNO3, 1 mol L-1 NH4OAC, Mehlich 1, 0.002 mol L-1 SrC12 ＋ 0.05 mol L-1 citric acid, and ammonium bicarbonate-diethylenetriamine pentaacetic acid （AB-DTPA）. A plot of cumulative amounts of K released showed a discontinuity in slope at 168 h. Thus, two equations were applied to two segments of the total reaction time （2-168 and 168-2 017 h）. Cumulative amounts of K released ranged from 55 to 299 mg kg-1 in 2-168 h and from 44 to 119 mg kg-1 in 168-2 017 h. Release kinetics of K in the two time segments conformed fairly well to parabolic diffusion, simplified Elovich, and power function models. There was a wide variation in the K release rate constants. Increasingly higher average concentrations of soil K were extracted by distilled water, Mehlich 1, SrC12, CaC12, SrC12 ＋ citric acid, AB-DTPA, MgNO3, NaCI, NH4OAc, BaCI2, and HNO3. Potassium release rate constants were significantly correlated with K extracted. The results of this study showed that information obtained from mathematical modeling in two reaction time segments can help to estimate the K-supplying power of soils.

关键词： chemical extraction calcareous soils mathematical modeling release rate constant time segments