Łukasz Klapiszewski, Magdalena Nowacka, Katarzyna Siwińska-Stefańska and Teofil Jesionowski
Advanced silica/lignosulfonate composites were obtained using magnesium lignosulfonate and silica precipitated in a polar medium. For comparative purposes analogous synthesis was performed using commercial silica Aerosil®200. Lignosulfonates are waste products of paper industry and their application in new multifunctional materials is of great economic interest. The composites obtained were subjected to thorough characterization by determination of their physicochemical, dispersive-morphological and electrokinetic properties. Their particle size distribution was measured, SEM images were taken, FT-IR analysis and colorimetric study were made, thermal and electrokinetic stabilities and parameters of porous structure were also determined. The results can be of interest in further application studies
Patrycja Wojciechowska, Aleksandra Heimowska, Zenon Foltynowicz and Maria Rutkowska
Degradability of organic-inorganic cellulose acetate butyrate hybrids in sea water
Environmental degradability of novel organic-inorganic cellulose acetate butyrate hybrids obtained via solgel process was investigated. The degradation of hybrids was studied under marine exposure conditions in the Baltic Sea for a period of 25 weeks. The influence of characteristic parameters of sea water on the degree of degradation monitored by changes of weight and optical microscopy was discussed. The degraded samples were also examined by FT-IR spectroscopy. It has been established that the CAB/silica hybrids are more susceptible to biodegradation in sea water environment than pure cellulose acetate butyrate.
Yufeng Ma, Xiang Geng, Xi Zhang, Chunpeng Wang and Fuxiang Chu
A novel 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ-amino propyl triethoxy silane (KH550) was synthesized and introduced on the surface of wood fiber. Finally DOPO-g-KH550 treated wood fiber (DKTWF) was used to prepare DKTWF composite phenolic foams (DKTWFCPF). The structures of DOPO-g- KH550 was acknowledged by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR). The structures of DKTWF were confirmed by FT-IR. Compared with wood fiber, the diffraction peaks’ position was basically unchanged, but the crystallinity was slightly increased and thermal stability were dramatically improved, T5% and Tmax increased by 21.9o and 36.1o respectively. But the char yield (800o) was slightly reduced. With the dosage of DKWF, there were different degrees of improvement including the mechanical properties, flame retardancy and microstructure of DKTWFCPF. Comprehensive analysis, the interfacial compatibility was significantly improved between DKTWF and phenolic resin, and the suitable content of DKTWF was 4%.
An attempt has been made to recycle Styrofoam waste to a novel functional polymer, Phenyl thiosemicarbazone surface (PTS). Polystyrene (PS) obtained from Styrofoam waste was acetylated and then condensed to PTS by reacting it with 4-Phenyl-3-thiosemicarbazide ligand and characterized by FT-IR spectroscopy and elemental analysis. Synthesized PTS was applied successfully for the treatment of lead contaminated water by batch extraction method. Sorption variables were optimized (pH 8, adsorbent dose 53mg, initial Pb(II) ion concentration 10mgl-1 and agitation time 90min) by factorial design approach. Lead uptake by PTS was found much sensitive to the pH of Pb(II) ion solution. The maximum removal (99.61%) of Pb(II) ions was achieved at optimum conditions. The Langmuir and D-R isotherm study suggested the monolayer, favorable (RL=0.0001-0.01) and chemisorption (E=20.41±0.12kJmol-1) nature of the adsorption process. The sorption capacity of PTS was found to be 45.25±0.69mgg-1. The FT-IR spectroscopy study showed the involvement of nitrogen and sulphur of thiosemicarbazone moiety of PTS for the uptake of Pb(II) ions by five membered chelate formation.
Polyacrylamide-zeolite composite was prepared by direct polymerization of polyacrylamide in suspensions of β-zeolite. Phytic acid was then immobilized on the composite surface. Fourier transform infrared spectrometry (FT-IR), X-Ray Diffraction (XRD) and Thermal gravimetry (TG) techniques were employed to characterize the synthesized adsorbent. The adsorptive features of the composite and the modified composite were investigated for the removal of Pb2+ from aqueous solution in view of dependency on pH, time, ion concentration, temperature, selectivity, kinetics and reusability. The adsorption isotherms were evaluated with reference to the Langmuir and Freundlich models. Thermodynamic of the system was calculated. ΔG<0 indicated that the adsorption process was spontaneous. Good compatibility of the adsorption kinetics to the pseudo-second-order model predicted that the rate-controlling step was a chemical sorption. The selectivity experiments showed that the adsorbents were selective toward Pb2+ in the presence of Zn2+ and Cd2+. The reusability of the adsorbent was tested for four regeneration cycles.
Vinyl ester resin (VEOCN) was prepared from o-cresol epoxy resin (EOCN) and methacrylic acid in the presence of triphenyl phosphine as catalyst and hydroquinone as inhibitor with acid value of ~ 7 mg of KOH per gram of solid. O-cresol based novolac resin (OCN), OCN based epoxy resin (EOCN) and VEOCN were characterized by Fourier transform infra red spectroscopy (FT-IR), 1H-NMR and 13C-NMR. The thermal and mechanical behavior of the samples prepared at 30°C from VEOCN using styrene and methyl-methacrylate respectively as reactive diluents, in the presence of benzoyl peroxide (2 phr) as initiator was studied using Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TGA) and Universal Testing Machine (UTM). Chemical resistance of above VER samples was also evaluated as a function of % weight loss and with the help of Scanning Electron Microscopy (SEM), upon immersing the VEOCN samples in different solutions for 90 days.
Modified PVC (M-PVC) material with suppressed migration and low glass transition temperature was prepared via click reaction of a monooctyl phthalate derivative. Chemical structure and composition of M-PVC were characterized by FT-IR, 1H NMR and element analysis. Thermal stability, glass transition temperature and migration stability of M-PVC were studied with TGA, DSC and migration tests, respectively. The study showed that M-PVC exhibited poor thermal stability, and low glass transition temperature of 66.0°C. No migration was found in distilled water, 10% (v/v) ethanol, 30% (w/v)acetic acid and petroleum ether. The PVC material is expected to preparing PVC products in the areas with high migration resistance requirement.
Li Cong, Zhang Li, Zhang Guanqun, Xu Jianguo and Zhang Long
The dissolution of corn stover in alkaline solvent system composed of NaOH-H2O2 was reported and the separation of its ingredients combined with acid precipitation, ethanol extraction was proposed. It is proven that the residual after alkali solvent was cellulose, the filtrate by the acid precipitation of the liquor was lignin, the solid by the ethanol extraction of the liquor was hemicellulose. The optimum dissolution conditions were determined by single-factor experiment as follows: the concentration of H2O2 5.0%, pH 11.5, dissolution temperature 60°C, dissolution time 3.0 h, the ratio of liquid to solid 30 mL/g. And chemical analysis were employed to determine the purity of the components separated. The structure of the components separated were identifi ed by FT-IR, SEM, XRD and NMR. The cellulose recovery yield can achieve to 84.2% and lignin recovery yield is 86.6%, the hemicellulose recovery yield is 96.7%. After recycling the solvent 3 times, the recovery yield of cellulose, lignin and hemicellulose were 82.7, 87.6 and 97.4%, and the purity of cellulose, lignin and hemicellulose were 98.0, 96.5 and 98.7%, respectively.
P. Thamilarasu, G. Kumar, R. Tamilarasan, V. Sivakumar and K. Karunakaran
Kinetic, Equilibrium and Thermodynamic studies on the removal of Cr(VI) by activated carbon prepared from Cajanus Cajan(L) Milsp seed shell
This paper presents the feasibility of the removal of hexavalent chromium ions from aqueous solutions by using activated carbon prepared from Cajanus Cajan(L) Milsp. It was carbonized and activated by treating it with concentrated sulfuric acid followed by heating for 5 h at 500°C. Batch adsorption experiments were carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage and temperature. The experimental data fitted well to the Freundlich isotherm. The thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were calculated, which indicated that the adsorption was spontaneous and endothermic in nature. The adsorbent used in this study was characterized by FT-IR and SEM before and after the adsorption of metal ions. The results indicate that Cajanus Cajan(L) Milsp can be employed as a low cost alternative and commercial adsorbents in the removal of chromium (VI) from water and waste water.
Elton Souza, Valtair Cristante, Pedro Padilha, Sonia Jorge, Marco Martines, Rafael Silva, Devaney Carmo and Gustavo Castro
Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium
A method was developed to attach 2,2-bipyridine (BP) onto a silica gel surface by a two-step reaction. The first step consisted of a reaction between the matrix and a silylating agent, 3-chloropropyltrimethoxysilane. In the second step of the reaction, a ligand molecule was attached onto Si-CPTS, yielding the product Si-BP. The modified material contained 0.431±0.01 mmol of 2,2-bipyridine per gram of modified silica, as confirmed by FT-IR spectra of the proposed structure. The surface modification was characterized by the BET technique, which revealed a decrease in the surface area from 614 to 450 m2 g-1. The series of adsorption isotherms for the metal ions were adjusted to fit a modified Langmuir equation. The maximum number of moles of copper, cadmium and lead ions adsorbed was 0.64, 0.53, and 0.54 mmol g-1, respectively. The surface saturation was calculated as φ fraction and the values obtained, Cu(II) = 1.160, Cd(II) = 1.044 and Pb(II) = 0.997, suggest a type 1:1 metal-ligand complex.