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Run Fang,Xiansu Cheng,Wu-shi Lin
BioResources , 2011,
Abstract: Dimer acid (DA) was grafted onto lignin (EHL) to form a graft copolymer DA-g-EHL. The selection of the reaction type and the optimization of the reaction conditions for the grafting reaction were conducted through orthogonal and single factor experiments. FT-IR and thermal analysis were used to characterize the graft product. It was found that, compared with free radical grafting, DA can be grafted onto EHL more effectively by ester condensation with strongly acidic cation exchange resin as a catalyst. Under optimum reaction conditions, the increase of acid value and the yield of graft copolymer can reach about 9.3% and 83%, respectively. The application of DA-g-EHL in preparing modified phenolic aldehyde amine curing agent (PAA) was studied. Results showed that the flexibility of the epoxy resin cured by DA-g-EHL modified PAA is significant higher than that of the resin cured by EHL modified PAA. The graft of DA onto EHL may reduce the rigidity of EHL and the chain stiffness of the PAA modified by EHL.
Preparation of lignin derivatives and their application as protease adsorbents  [PDF]
Run Fang, Yin Lin, Xian-Su Cheng
Natural Science (NS) , 2009, DOI: 10.4236/ns.2009.13024
Abstract: Synthesis of two lignin derivatives, lignophenol and lignin-aminophenol, were presented in this article. The chemical structure and the func-tional groups of lignin derivatives were charac-terized through FT-IR analysis. The immobiliza-tion of three proteases (papain, trypsin and pepsin) on lignin and lignin derivatives was carried out using adsorption technique. The influence of contact time and pH on the enzyme adsorption by different adsorbents was inves-tigated. Furthermore, enzyme activity recovery was also evaluated. Results showed that lignin and lignin derivatives could adsorb proteases effectively and the adsorption capacity of lingo- phenol and lignin-aminophenol was higher than that of pure lignin. Meanwhile, the activity re-covery of papain and pepsin immobilized on lignin derivatives was very high. This pheno- menon suggested that there is a supramole- cular interaction between enzymes and lignin derivatives which do not inhibit enzyme activity. Therefore, lignophenol and lignin-aminophenol are both promising adsorbents for enzyme im-mobilization under acid and neutral conditions.
Advances in research and application of water-treatment flocculants

Liu Rui,Zhou QiXing,Zhang LanYing,Wang Bing,Sun PiWu,

应用生态学报 , 2005,
Abstract: Water-treatment flocculants are being developed from traditional to inorganic,from inorganic to organic,from natural organic to synthetic organic,from synthetic organic to modified natural organic,from inorganic or organic to inorganic-organic,and from chemical to biological with ecological safety.In order to promote the rapid development and practical application of water-treatment flocculants,the research progress and application situation of flocculants for water treatment at home and abroad were reviewed.In particular,the characteristics of two important flocculant types,chemical and microbiological flocculants,as well as their application processes in water treatment were summarized,their development orientations were analyzed and evaluated,and the future research directions aimed to overcome the current shortages in developing and applying flocculants in China were put forward.
Flocculants application for precipitation and separation of proteins from Lens culinaris cv. Tina
Barbara Baraniak,Micha? ?wieca,Agnieszka S?owik
Acta Scientiarum Polonorum : Technologia Alimentaria , 2009,
Abstract: Background. Lentil (Lens culinaris) is an important crop in many developing countries. Usefulness of protein isolates in the human nutrition and animal feeding have been also studied. Improvement of protein precipitation and fractionation efficiency by using different flocculants was the aim of this study. Material and methods. The polyelectrolytes Magnafloc LT-22 and Magnafloc LT-25 were tested in the process of coagulation and fractionation of protein from lentil protein extracts. Proteins were extracted from flour with 0.5 M NaCl in the 50 mM Tris-HCl buffer pH 7.5 and 2 mM NaOH at ratio 1:10. Protein were coagulated at different pH (6, 5, 4, 3) using flocculants in three different concentration 0.1, 0.3 and 0.5%. Samples were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results. Influence of extraction medium on the yield and quality of protein was visible. In all studied cases proteins were the most effective precipitated with Magnofloc LT-25. Application of different pH condition for coagulation caused fractionation of lentil protein. Gel electrophoresis of protein of all studied samples showed different molecular weight subunit patterns ranging from 8 to 102 kDa. Conclusions. Using of flocculants as coagulating factors allows obtaining a high concentrated protein isolates, however the yields of flocculation were determined by different extraction systems, concentration of flocculants and pH condition of process.
Preparation of Nano-Modified Polyacrylamide and Its Application on Solid-Liquid Separation in Waste Drilling Mud  [PDF]
Fanghui Wang, Jiantao Fan, Hong Zhu, Kefei Han, Jing Zou, Haiyun Sun
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.12006
Abstract: To satisfy the requirement on solid-liquid separation in high-density waste drilling mud, prepare the nano-modified polyacrylamide(PAM) flocculant for high density waste drilling mud by in-situ dispersion method, direct dispersion method and simultaneous formation method. The result showed the flocculent effect of nano-modified polyacrylamide prepared by simultaneous formation method was the best. When the content of water glass and acrylamide(AM) were respectively 3% and 15% , reaction temperature was 60?C and reaction time was 3h, the performance of product was the best. The water content in filter cake was 24.32% after the waste drilling mud disposed by the optimization flocculant. The flocculent effect of optimization flocculant was superior to that of other flocculant in market.
"Preparation and application of dimer acid/lignin graft copolymer,"  [PDF]
BioResources , 2015,
Jian Li,Shujun Li,Haigang Wang,Yang Yang
BioResources , 2011,
Abstract: Enzymatic hydrolysis (EH) lignin was modified with formaldehyde. TG-DSC and PY-GC-MS analysis methods were adopted to characterize the differences between EH lignin and the modified lignin. The modified lignin was then mixed with wood sawdust and made into a lignin-based composite under the following conditions: pressure of 2 to 5 MPa, temperature of 175 to 190 oC, and the modified lignin dosage of 20% to 70%. The effects of pressure, temperature, and the modified lignin dosage on the properties of the composites were also evaluated. The pressure of 2 MPa was not enough to make a strong composite, and the composite with low dosage of modified lignin could not resist water, which signifies pressure and the ratio of modified lignin to sawdust are vital factors. Temperatures of 175 oC and 190 oC did not make much difference to change the mechanical properties of the composites. The composites which were made under 3 MPa, 180 oC, and the ratio of 1:1 modified lignin to wood sawdust was of fair quality. The samples made with the modified lignin dosage of 70% under 2MPa at 180 oC for 10min showed a low thickness swelling and low rates of water absorption from humid air and liquid water. Their free formaldehyde contents were also low and met Grade 2 in the national standard of China.
Theodor Malutan,Raluca Nicu,Valentin I. Popa
BioResources , 2008,
Abstract: The chemical modification of lignin through hydroxymethylation and epoxidation is a way to develop new application fields and improvement of lignin performances. In this paper the influence of reaction conditions was studied using different samples of unmodified and modified lignins from annual plants (Wheat straw and Sarkanda grass). The progress of reactions was monitored by evaluating the epoxy index. The resulting products were characterized by FTIR-spectra, UV-Vis spectroscopy, and thermogravimetry analysis. The products obtained were tested to be used in composite formulation for wood applications.
Nour Eddine El Mansouri,Qiaolong Yuan,Farong Huang Mail
BioResources , 2011,
Abstract: Epoxidization is an interesting way to develop a new application of lignin and therefore to improve its application potential. In this work, kraft lignin-based epoxy resins were obtained by the epoxidization reaction, using the kraft lignin recovered directly from pulping liquor and modified by a methylolation reaction. The methylolated lignins were obtained by the reaction of original kraft lignin with formaldehyde and glyoxal, which is a less volatile and less toxic aldehyde. 1H-NMR spectroscopy showed that methylolated kraft lignin has more hydroxymethyl groups than glyoxalated kraft lignin. For the epoxidization reaction we studied the influence of the lignin:NaOH (w/w) ratio, temperature, and time of the reaction on the properties of the prepared epoxidized lignins. The structures of lignin-based epoxy resins were followed by epoxy index test and FTIR spectroscopy. Optimal conditions were obtained for lignin-based epoxy resin produced at lignin/NaOH = 1/3 at 70 oC for 3h. Thermogravimetry analysis (TGA) revealed that the epoxidization enhances the thermal stability of lignins and may allow a wider temperature range for applications with lignin epoxy-PF blends.
Preparation of a silica gel modified with 2-amino-1,3,4-thiadiazole for adsorption of metal ions and electroanalytical application
Dias Filho, Newton L.;Caetano, Laércio;Carmo, Devaney R. do;Rosa, André H.;
Journal of the Brazilian Chemical Society , 2006, DOI: 10.1590/S0103-50532006000300007
Abstract: silica gel with a specific area of 382 m2 g-1 and an average pore diameter of 60 ? was chemically modified with 2-amino-1,3,4-thiadiazole, for the purpose of selective adsorption of heavy metals ions and possible use as a chemically modified carbon paste electrode (cmcpe). the following properties of this functionalized silica gel are discussed: selective adsorption of heavy metal ions measured by batch and chromatographic column techniques, and utilization as preconcentration agent in a chemically modified carbon paste electrode (cmcpe) for determination of mercury(ii). the chemical selectivity of this functional group and the selectivity of voltammetry were combined for preconcentration and determination.
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