ASSESSMENT OF TOXICITY OF INDUSTRIAL WASTES USING CROP PLANT ASSAYS

Environmental pollution has a harmful action on bioresources, including agricultural crops. It is generated through many industrial activities such as mining, coal burning, chemical technology, cement production, pulp and paper industry, etc. The toxicity of different industrial wastes and heavy metals excess was evaluated using crop plant assays (germination and hydroponics seedlings growth tests). Experimental data regarding the germination process of wheat (from two cultivars) and rye seeds in the presence of industrial wastes (thermal power station ash, effluents from a pre-bleaching stage performed on a Kraft cellulose – chlorinated lignin products or chlorolignin), along with use of an excess of some heavy metals (Zn and Cu) are presented here. Relative seed germination, relative root elongation, and germination index (a factor of relative seed germination and relative root elongation) were determined. Relative root elongation and germination index were more sensitive indicators of toxicity than seed germination. The toxic effects were also evaluated in hydroponics experiments, the sensitivity of three crop plant species, namely Triticum aestivum L. (wheat), Secale cereale (rye), and Zea mays (corn) being compared. Physiological aspects, evidenced both by visual observation and biometric measurements (mean root, aerial part and plant length), as well as the cellulose and lignin content were examined

PREPARATION AND CHARACTERIZATION OF COMPOSITES COMPRISING MODIFIED HARDWOOD AND WOOD POLYMERS/POLY(VINYL CHLORIDE)

Chemical modification of hardwood sawdust from ash-tree species was carried out with a solution of maleic anhydride in acetone. Wood polymers, lignin, and cellulose were isolated from the wood sawdust and modified by the same method. Samples were characterized by Fourier transform infrared spectroscopy (FTIR), providing evidence that maleic anhydride esterifies the free hydroxyl groups of the wood polymer components. Composites comprising chemically modified wood sawdust and wood polymers (cellulose, lignin)-as variable weight percentages-, and poly (vinyl chloride) were obtained and further characterized by using FTIR spectroscopy and scanning electron microscopy (SEM). The thermal behavior of composites was investigated by using the thermogravimetric analysis (TGA). In all cases, thermal properties were affected by fillers addition

CHEMICAL MODIFICATION OF BEECH WOOD: EFFECT ON THERMAL STABILITY

Beech sawdust was reacted with phthalic (PA) and maleic (MA) anhydrides for chemical modification. The influence of reaction time and anhydride amount was investigated. IR spectra gave evidence of wood esterification. Thermogravimetric investigation of chemically modified wood indicated a better thermal stability (mainly for wood treated with phthalic anhydride) in comparison with the untreated wood

STRUCTURAL CHANGES EVIDENCED BY FTIR SPECTROSCOPY IN CELLULOSE MATERIALS AFTER PRE-TREATMENT WITH IONIC LIQUID AND ENZYMATIC HYDROLYSIS

Attempts were made to enhance the hydrolysis of Asclepias syriaca (As) seed floss and poplar seed floss (PSF) by cellulase after pre-treatment with ionic liquids. Two ionic liquids, namely 1-butyl-3-methylimidazolium chloride [BMIM]Cl and 1-ethyl-3-methylimidazolium tetrachloroaluminate [EMIM]Cl-AlCl3, were used. In comparison with conventional cellulose pretreatment processes, the ionic liquids were used under a milder condition corresponding to the optimum activity of cellulase. Hydrolysis kinetics of the IL-treated cellulose materials was significantly enhanced. The initial hydrolysis rates for IL-treated cellulose materials were greater than those of non-treated ones. The structural modifications of hydrolyzed cellulose materials were analyzed using FTIR spectroscopy

Green Composites Comprising Thermoplastic Corn Starch and Various Cellulose-Based Fillers

Starch microparticles (SM) were prepared by delivering ethanol as the precipitant into a starch paste solution dropwise. Chemically modified starch microparticles (CSM) were fabricated by a reaction with malic acid using the dry-preparation technique. Composites were prepared using CSM and various cellulose materials as fillers within glycerol plasticized–corn starch matrix through the casting process. Microcrystalline cellulose (MC, as reference filler) and two cellulose-enriched materials, namely Asclepias syriaca L. seed hairs (ASSH) and Populus alba L. seed hairs (PSH), were compared in terms of morphology and performance when incorporated within the CSM/S thermoplastic matrix. The effects of cellulose fillers on the morphology, surface, water sorption, and mechanical properties were investigated. The surface water resistance of composite materials was slightly improved through addition of cellulose fillers. Samples containing cellulose fillers presented higher tensile strength but lower elongation values compared with those without fillers