Journal of Applied Research in Chemistry
Year:2012 | Volume:6 | Issue:2|Papers Count:10

A microbial-based biosensor for BOD determination of industrial and municipal wastewaters was designed and optimized. Operating conditions during measurement of BOD samples have a great impact on the sensor. So, selection of the most suitable values for operating conditions and parameters affecting the BOD biosensor performance for accessing a highly accurate measurement is necessary. A Clark cell was used as the transducer and activated sludge collected from water and wastewater treatment plant of Shahinshahr, Iran, pretreated and used as the biological receptor. The effects of the volume of sludge immobilized on the sensor, pH of carrier fluid, flow rate of carrier fluid and volume of sample injection on the biosensor performance were studied. The optimum values for volume of sludge immobilized on the sensor, pH and flow rate of carrier fluid, and volume of sample injection were obtained equal to 500 ml, 7, 0.9 ml/min and 3 ml, respectively.

In this research, the effect of isocyanate coupling agent (Hexamethylene diisocyanate) on physical and mechanical properties of old cartoon fiber / high density polyethylene composite was investigated. Components of composite were compound via melt mixing during extrusion by twin screw, counter rotating compounder. The mechanical and physical properties of composite samples such as flexural strength, tensile strength, tensile modulus, flexural modulus, impact strength, elongation at break, hardness and water absorption for 2h and 24h were measured.The mechanical results revealed that, by adding isocyanate base coupling agent, all mechanical properties except impact strength increased. Also, by adding coupling agent, water absorption 2h after and 24h decreased. The SEM observations were shown that, adhesion between old cartoon fiber and polymer matrix was improved by adding the coupling agent.

In this Research, Comparison of leaching and bioleaching processes for extracting copper from low-grade ore at Sarcheshmeh Copper Mine Complex has been investigated.Investigations were applied to find the effects of parameters such as pH, temperature, as well as liquid irrigation flow in semi-industrial scale in column reactor for 90 days. Results obtaind from column tests showed that bacterial leaching processes using mesophilic bacterial in comparison with chemical leaching at ambient temperature increase the amount of copper and iron extraction by 24.93% and 9.30%, respectively. Also, using moderate thermophilic bacteria at 50 oC, pH=1.5 and rate of irrigation=5 liter per meter square per hour increased copper extraction about 36% in comparison with chemical leaching. However, the maximum copper extraction was 81.87%.

In this work, separation process of a simulated refinery gas stream of eight components including hydrogen and light hydrocarbons C1-C4 through MFI-type zeolite membrane was studied in a broad temperature range and under different feed-stream pressures. A modified Langmuir model is used to correlate the experimental data. Separation results of the zeolite membrane characterized by the model considering competitive adsorption of hydrocarbons over hydrogen and configurational diffusion in the zeolite pores. The bell-shaped flux temperature profile in the temperature range of 25-300 oC is clearly a balanced result of these two opposite driving forces for HC permeation. At a given feed pressure, hydrogen flux increases monotonically with temperature. Increasing feed gas pressure shifts the flux-temperature profile toward higher flux direction. At room temperature (25 oC), hydrogen flux is almost zero. The selectivity of hydrogen had a weak dependence on the feed pressure.

The present study was carried out to investigate the efficiency of removal of anionic dye Acid Blue 25 (AB 25) from contaminated water by making use of hardened paste of Portland cement (HPPC) as a constitutional and low-cost material. The SEM images of the adsorbent show a porous surface that can trap the dye molecules. HPPC has been selected as the adsorbent because of its main advantages such as abundant availability, low-cost, good efficiency, technical feasibility, and simple separation of the sludge in end of the process. Investigation of the variables, such as contact time, initial dye concentration, adsorbent dosage and temperature shows that removal of AB 25 increases with increasing adsorbent dosage, temperature, contact time, and a decrease in the initial dye concentration. Based on our experimental results, it could be concluded that HPPC is an efficient and economical adsorbent for AB 25 removal.

Our aim for presenting this paper was synthesis of a bioactive ceramic nanocomposite.Motion nanocomposite was synthesized by two-step of sol-gel method. C16TAB surfactant was used as template. The pores were created after removal of surfactant by calcinations at 600 oC. The obtained results of FTIR demonstrated formation of silanol and siloxan groups of silica network and hydroxyl and phosphate groups of HA network. Also, TEM and EDS results confirmed presence of a layer of silica-mesoporous surrounding of HA crystals and the ED results showed that mesoporous silica was an amorphous while hydroxyapatite was a crystalline phase. Results of N2 adsorption-desorption analysis (BET) indicated that pores diameter average increased in the nanocomposite while specific surface area and pores volume decreased. At the end, bioactivity behavior by ICP analysis was examined. The results indicated that presence of hydroxyapatite phase and increasing of pores diameter average in nanocomposite improved bioactivity behavior of silica-mesoporous.

We have been successfully prepared molybdenum carbide nanostructures by mechanochemical method from molybdenite in the presence of aluminum powder, lime and carbon. The heat released from aluminothermy reaction assisted the reaction progress. Therefore, the reaction was performed in the presence of aluminum powder.The reaction was done without heating, and the sulfur that released during reaction progress was removed as calcium sulfide that was a solid composition without any environmental pollution.Various parameters such as milling time and different amounts of aluminum powder have been considered to achieve optimum conditions.The as-prepared samples were identified with X-ray diffraction (XRD) and scanning electron microscopy (SEM).

In this project a layer of macrocyclic Chlorosulfonyl-Calix [4] arene has been chemically bonded to the silica gel, and then multiple characterization techniques such as elemental analysis, scanning electron microscopy (SEM) and N2 adsorption-desorption (BET) was done.The results indicated that Chlorosulfonyl-Caix [4] arene has been chemically well-anchored on the surface of silica gel. Also, it was demonstrated that this newly prepared heterogeneous system have high binding ability toward sodium cations.So it can be used as an ionophore reagent in many chemical reactions.