THE APPLICATION OF CHEMISTRY IN ENVIRONMENT
Year:2010 | Volume:1 | Issue:2|Papers Count:8

The influence of different intensities of ultrasound on the molecular weight of chitosan was investigated. Average molecular weight of ultrasonicated chitosan was determined by measurements of intrinsic viscosity of samples. Intrinsic viscosity of samples decreased exponentially with increasing sonication time. The Schmidt polymer degradation model was used to analyze the molecular weight decay as a function of sonication time as well as rate constant determination. In addition, the structure of the degraded chitosan was characterized by FT-IR spectral analysis. There was no significant change of the total degree of deacetylation (DD) of degraded chitosan compared with the initial chitosan.

(100 sample) the soil samples were collected from mentioned regions at various seasons of the year a diluted at 10.2 dilution and spread on s.c.A special medium for achieving single colony. 150 samples isolated based on morphology and transfer to N.A for testing antibacterial effect with perpendicular streak method.20 samples have positive. Among this positive samples after isolation of antibacterial material with ethyl acetate and inoculation against Staphylococcus aureus (ATTC: 9341), Escherichia coli) ATTC: 10536) proteus vulgaris (ATTC: 29905) inhibition zone were measured. Among 20 sample 12 sample have inhibition zone above 1 ern that isolated for streptomyces samples that able to produce antibiotic and then for distinguishing different biochemical test were subjected with jacard cluster analysis.on the base of this determined characteristics of streptomyces strain in first group is s.americanus, s.atratlls, s.anthocyanicus were identified of antibiotic producers. Another 2 groups could be concluded they are close to the genera streptoverticlum, nokardia with different species.

In this article the equilibrium properties of pure and doped carbon nanotubes in various condition by molecular simulation method was investigated. The carbon nanotube has exclusive thermodynamic properties that whit adding other atoms for example boron, thispropertiesare changed. Molecular simulation method is useful tools to investigate the thermodynamic properties at nanoscale. Equilibrium property of doped carbon nanotubes in water solvent is exclusive properties of this system. Water is someone important and applicable solvent that many investigations for this exclusive property are done. abilty for creating hydrogen bonding give exclusive properties.By using of molecular simulation software in Monte Carlo method and radial distribution function for carbon and boron atoms in nanotubes and oxygen and hydrogen atoms in water, hydrophobicity and hydrophilicity of these nanotubes investigated. Monte Carlo simulation done by Mcccs Towhee software and Molecular dynamic done by DL-POLY software. spc model selected for water molecule. Radial distribution function (RDF) which is important in the theory of simple fluids (gases and liquids) because many thermodynamic quantities can be determined from it, used for pure and doped carbon nanotubes. MOPAC quantum chemistry software used for charge distribution in nanotubes.

In this study chitosan hydrogel beads with porosity ~ 0.86 and diameter ~ 2±0.07 mm were prepared from 85% deacetylated chitosan for removal of Cd2+ ions from aqueous solutions. Chitosan powder was dissolved into dilute acetic acid as solvent and formed into spherical beads using a phase inversion technique. The effect of temperature, initial concentration of Cd2+ ions, and the period of agitation were perused to achieve the best isotherm model. Kinetic studies of the adsorption phenomena were conducted in a batch system by initial concentrations from 100 to 500 mgL-1 until the equilibrium concentration Ce (mgL-1) was reached. To investigate the surface morphology of the chitosan beads before and after adsorption process, they were observed by the use of Scanning Electron Microscopy (SEM). The surface characterization of the beads .in both cases showed metal ions binding toward the surface of porous chitosan beads. All of the experiments carried out at pH of 6.3 and agitation rate of 200 rpm. Results show that wastewater treatment by Biopolymers is possible and may compete and/or replace the prevailing conventional methods.

The Purpose of this Review is to Study the Whole Chemical Mechanisms Happening in the Cooked Foods which Lead to Acrilamid Formation.Learning about These Mechanisms, International Food Safety Experts Found the fact that the Best Program to Reduce Undesirable Effectsof Acrilamid Formation in Foods (Cancer Risk) is to Obligate Food Producers to Improve Product Procedure in Foods Specially the One with Higher Risk of Acrilamid Formation.As a Matter of Fact, Having Proper Knowledge About The Reactions and Effective Components in Acrilamid Formation is Essential to Measure and Control This Mechanisms.According to the Mentioned Points We Review The Existence Theories About Chemical Mechanisms for Acrilamid Formation, From Free Amino Acids And Reducing Sugars, or in Another Chemical Reactions Form Acrolein and Also Through Millard Reaction.Also we Assessed The Effective Factors in This Reactions Such as: pH, Humidity, Temperature and Time of Heating The Results Slow that Comparing With The Other Amino acids, The Asperagin Effective Substance in React With Reducing Sugar Specially (D-Glucose) Which Leads to Acrilamid Formation. Breed and Potato are Rich Sources of Asperagin so Heating and Frying Process Result in more Acrilamid Formation in These Kinds of Foods.Consequently The Best Plan to Reduce Acrilamid hazard in Food is to Encourage Food Industries Authorities to Improve Their Technologies in Order to Control Acrilamid Level in Foods. Also All The Measures Should Be Taken to Educate and Recommend Consumers to Have a Balanced Diet.

The zwitterionic intermediate created from the reaction between dichlorocarbene and acetylenic esters is trapped by aromatic aldehydes to afford poly functionalized furans in fairly good yields...

Advanced oxidation processes of glucose and starch from aqueous solution by using ozone has been studied.A nominal concentration of 100 mgL-1 of the glucose and starch was chosen, which normally occurs in food industry wastewaters. The effect of oxidation concentration and pH on COD and TOC has been studied. It was observed that the highest removing rate of these factors achieved at alkaline and some neutral conditions, i.e., the indirect mechanism of hydroxyl radical attack on the molecule under study.

Reaction of 2-bromo-1, 4-naphthaquinone with thiols in chloroform or dichloromethane caused substitution of thioalkyl (aryl) on potions 3 and producing 2-bromo-3-thioalkyl (aryl) -1, 4-dihydroxynaphthalene, which under oxidation gave the corresponding 1, 4-naphthaquinone. While the reaction in presence of sodium acetate in ethanol gave 2-thioalkyl (aryl) - 1, 4-naphthaquinones by substitution with bromine. Reaction of bromonaphthaquinone with hydroxylamine hydrochloride gave 2-amino-3-bromo-1, 4-naphthaquinone. The reaction of bromonaphthaquinone with isoxazole-5 (2H)-ones under reflux condions in ethanol produced 2-ethenylamino-3-bromonaphthaquinone derivatives.