Kinetic Study

Real time Fourier transform infrared (RTFT-IR) spectroscopy reveals the influence of the nature of the photoinitiator on the kinetics for the polymerization reaction. Real time cure monitoring was used to determine the polymerization rate of ultraviolet cured unsaturated polyester resins (UPR1:2-1:5) based on palm oil and containing styrene as a cross-linking agent in the presence of IRGACURE 184 photoinitiator. Firstly, variable types of UPR1:2-1:5 were prepared using various ratios of monoglyceride (MG) monomer to maleic anhydride which used as a source of double bond using polycondensation technique. RTFT-IR spectroscopy was used to characterize the ultraviolet curing kinetics for all the systems. This technique offered a powerful approach for monitoring changes in the chemical properties of the system during the ultraviolet curing. Pseudo first order kinetics for all UPR1:2-1:5 curable systems were determined and the rate constant values and regression coefficients were calculated. Furthermore, the thermal behaviour and morphological features for the photo-fabricated UPR1:2-1:5 systems were examined. The thermal analyses for the cured films were evaluated by TGA, DTG and DSC in nitrogen atmosphere at a heating rate of 10°C/min. All the formulations showed similar degradation pattern at 40 % and 50 % weight losses (Td = 40% and Td =50% respectively) except polymer UPR1:5 which had somewhat lower degree in the same range. In addition, the morphological properties for photo-fabricated UPR1:2,1:3,1:5 were investigated by using scanning electron microscopy.

The methylene blue (MB) absorption onto neem leaf
powder was investigated in term of both adsorption efficiency
and kinetic study. The effects of operation parameters i.e., MB
concentration, time of adsorption, adsorbent dosage, pH of
solution and temperature were investigated. The results showed that all parameter could affect the adsorption efficiency. The adsorption isotherm and kinetics over various pH and temperature were also studied. It was found that the adsorption capacity was increased with pH and temperature increased; suggested the exothermic process. The experimental data showed that the MB adsorption was fitted with Langmuir isotherm and the kinetic model was the pseudo-second order.

Adsorption of Co(II) ions from aqueous solutions onto Tea and Coffee powders has been examined in a batch adsorption process. The adsorption of Co(II) ions was found to be dependent on contact time, pH of solution, initial metal ion concentration, and adsorbent dose. The experimental equilibrium adsorption data were studied by Langmuir, Freundlich, Temkin and. The Langmuir model display demonstrated a superior fit than the other three models by higher correlation coefficient, R 2. The maximum adsorption capacities calculated from the Langmuir isotherm model were 244 mg/g, for both coffee and tea at optimum circumstances. The kinetic studies denoted that the adsorption process of Co(II) ions followed well pseudo-second-order model. According to the adsorption capacity, coffee and tea powder considered as an effective, low cost, and environmentally friendly adsorbent for the removal of Co(II) ions from aqueous solutions.

Cementation is one of the simplest and low cost methods. It is widely used in industry for recovery of metal and removal of metal ions from dilute wastes, and for purification of solutions. In the present investigations, copper powder was prepared by cementation from a copper sulphate solution of 0.08 M by slowly adding the activated iron powder. Activation of iron powder was done by milling it in an attrition mill. Kinetics of the cementation reaction was evaluated by measuring the rate of decrease of metal ions concentration in the solution by spectro-photometry. Studies of the results have shown significant improvement in the cementation rate. Cemented copper powder obtained was characterized for its purity, particle size, grain size and morphology by EDS, laser particle size analyser, XRD studies, TEM and SEM, respectively. The cemented copper powder was found to have particle size in the range of 180 nm to 46 μm having polygon shape. The average grain size in the powder particles was found to be 54 nm. Few core-shell particles with entrapped iron in copper particles have also been detected.

Adsorption of Co(II) ions from aqueous solutions onto Tea and Coffee powders has been examined in a batch adsorption process. The adsorption of Co(II) ions was found to be dependent on contact time, pH of solution, initial metal ion concentration, and adsorbent dose. The experimental equilibrium adsorption data were studied by Langmuir, Freundlich, Temkin and Dubinin-Radushkevic isotherms models. The Langmuir model display demonstrated a superior fit than the other three models by higher correlation coefficient, R2. The maximum adsorption capacities calculated from the Langmuir isotherm model were 244 mg/g, for both coffee and tea at optimum circumstances. The kinetic studies denoted that the adsorption process of Co(II) ions followed well pseudo-second-order model. According to the adsorption capacity, coffee and tea powder considered as an effective, low cost, and environmentally friendly adsorbent for the removal of Co(II) ions from aqueous solutions.

Shewanella xiamenensis G5-03 isolated from contaminated landfill soil efficiently decolorized five textile azo dyes under static conditions. One of them, Reactive Red 239 (RR239), was completely decolorized at a pH range of 7 to 11 (at 35°C) within 3-6 h. The bacterium was also efficiently decolorized RR239 in a wide temperature range of 25-40°C (at pH 8). The kinetics of RR239 decolorization by G5-03 fitted to the Michaelis-Menten Model (Km = 443.3 mg L-1 , Vmax = 166.7 mg L-1 h-1). The decolorization of RR239 was monitored by UV-Vis and FTIR spectroscopy, which showed significant changes in peak positions when compared to the dye spectrum. Overall, the ability of S. xiamenensis G5-03 to decolorize textile azo dyes in a wide range of temperatures and pH (neutral-alkaline) indicate that this strain is a potential candidate for treating dye-containing effluent.

This work focus on the study and the elaboration of microspheres based on amoxicillin (AMO), those microspheres were prepared through the oil/water emulsion evaporation technique. Polybutylene succinate (PBS) and Poly(methylmethacrylate) (PMMA) polymeric matrix were used with Tween 80 (T80) and Polyvinyl alcohol (PVA) as emulsifiers. These polymeric systems were analyzed by SEM, FTIR and optical microscopy. The conditions of the microspheres forming were varied and the preparation was performed by changing different parameters such as: the nature of the polymer, the stirring speed, organic solvent, surfactant nature, and concentration, which allows the study of their effect on encapsulation efficiency and drug release kinetics. These parameters affect strongly the size of microspheres, the drug content and the drug release, the latter is settled in an artificially reconstituted media of pH = 1.2 transcribed from the stomachal medium.

Adsorption of Co(II) ions from aqueous solutions onto Tea and Coffee powders has been examined in a batch adsorption process. The adsorption of Co(II) ions was found to be dependent on contact time, pH of solution, initial metal ion concentration, and adsorbent dose. The experimental equilibrium adsorption data were studied by Langmuir, Freundlich, Temkin and Dubinin-Radushkevic isotherms models. The Langmuir model display demonstrated a superior fit than the other three models by higher correlation coefficient, R2. The maximum adsorption capacities calculated from the Langmuir isotherm model were 244 mg/g, for both coffee and tea at optimum circumstances. The kinetic studies denoted that the adsorption process of Co(II) ions followed well pseudo-second-order model. According to the adsorption capacity, coffee and tea powder considered as an effective, low cost, and environmentally friendly adsorbent for the removal of Co(II) ions from aqueous solutions.

 Shewanella xiamenensis G5-03 isolated from contaminated landfill soil efficiently decolorized five textile azo dyes under static conditions. One of them, Reactive Red 239 (RR239), was completely decolorized at a pH range of 7 to 11 (at 35°C) within 3-6 h. The bacterium was also efficiently decolorized RR239 in a wide temperature range of 25-40°C (at pH 8). The kinetics of RR239 decolorization by G5-03 fitted to the Michaelis–Menten Model (Km = 443.3 mg L-1, Vmax = 166.7 mg L-1 h-1). The decolorization of RR239 was monitored by UV-Vis and FTIR spectroscopy, which showed significant changes in peak positions when compared to the dye spectrum. Overall, the ability of S. xiamenensis G5-03 to decolorize textile azo dyes in a wide range of temperatures and pH (neutral-alkaline) indicate that this strain is a potential candidate for treating dye-containing effluent.

This work focus on the study and the elaboration of microspheres based on amoxicillin (AMO), those microspheres were prepared through the oil/water emulsion evaporation technique. Polybutylene succinate (PBS) and Poly(methylmethacrylate) (PMMA) polymeric matrix were used with Tween 80 (T80) and Polyvinyl alcohol (PVA) as emulsifiers. These polymeric systems were analyzed by SEM, FTIR and optical microscopy. The conditions of the microspheres forming were varied and the preparation was performed by changing different parameters such as: the nature of the polymer, the stirring speed, organic solvent, surfactant nature, and concentration, which allows the study of their effect on encapsulation efficiency and drug release kinetics. These parameters affect strongly the size of microspheres, the drug content and the drug release, the latter is settled in an artificially reconstituted media of pH = 1.2 transcribed from the stomachal medium.