This study describes the adsorption and photocatalytic removal of methylene blue (MB) from aqueous solution by surface-modified TiO2 nanoparticles under ultraviolet irradiation in a batch system. The 5-sulfosalicylic acid grafted TiO2 (5-SA-TiO2) as a photocatalyst was characterized by means of XRD, FTIR and SEM techniques. The surface of TiO2 nanoparticles was modified by 5-sulfosalicylic acid (5-SA) to increase performance by altering surface properties. Notably, in contrast with the adsorption process, the remarkable removal enhancement of MB dye was observed by photocatalytic degradation process from aqueous solution. The adsorption and photocatalytic degradation kinetics of MB using 5-SA-TiO2 nanoparticles have also been investigated. The results show that the photocatalytic degradation was a good fit with the pseudo-first-order kinetic model (R2 > 0.99). The adsorption isotherm of MB onto modified TiO2 nanoparticles fitted into the Temkin equation. In addition, thermodynamic studies indicate the spontaneous behavior of adsorption and photocatalytic degradation processes.

This paper presents the synthesis, characterization of the nanocomposite of silver and chitosan polymer composite reinforced by cellulose fibre and its electrical behaviour in presence of water vapour. The coated paper has been characterized by XRD, IR, SEM and EDX techniques. The size of silver nanoparticles is found to be around 9 nm and deposited uniformly. Chitosan, as well as cellulose, contain a hydrogen attached to electronegative nitrogen and oxygen. This gives a favourable environment for the formation of hydrogen bonds. IR peaks of the composite infer the intermolecular hydrogen bonding between the two constituents. The SEM pictures show that the coating of the fibres with nanoparticles is quite uniform. EDX analysis shows that the coated filter paper has sufficient amount of silver along with carbon and oxygen. The coated paper shows good sensitivity towards humidity. It gives excellent linearity in response with a concentration of water vapour after heat treatment of composite at 130 °C. The sensitivity of the sensor is 0.8 M? per unit of relative humidity. Sensing properties originate from protonic conductivity from adsorbed water molecule.

In this work, performance of composite membranes was investigated for desalination of Kashan city’s water via pervaporation process. PEBA/PAN/PE, PEBA/PSF/PE and PEBA+NaX/PSF/PE composite membranes that used, was synthesized via a phase inversion route. For all experiments under 45?C, salt rejection was too high and equals to 99.9% that this quantity dropped by increasing the temperature that cause membrane swelling in high temperatures. Water contact angle and water take-up were measured to evaluate the hydrophilicity of the membrane. Also the effect of operating conditions including feed temperature and permeate pressure on permeability and selectivity is discussed. A permeate flux of 4.93 kg/m2h with salt rejection of 99.9% could be achieved at a feed temperature of 50 °C and a vacuum of 0.04 bar. Apparent diffusion coefficients of water at various permeate pressure and feed temperature are calculated. The most effective parameter was feed temperature.

This work attempted to determine the optimum conditions required for the coagulation and flocculation process as an essential stage of the ceramic wastewater treatment. Coagulation and flocculation is a very necessary step in industries as it lessens turbidity, color, and odor of wastewater. The experimental work was performed in several runs. The volume of wastewater used in each run was 200 mL and was kept at this value throughout. In certain runs, the speed of the mixer was varied while keeping the quantity of coagulant and flocculant constant in order to determine the optimum speed that resulted in the least turbidity. A speed of 5% was chosen as the ideal process speed according to the results obtained. Next, experiments were operated at this optimum speed while changing the dosage of coagulant and flocculant in order to decide the optimum dosage. Coagulant and flocculent amounts of 0.4 g (without booster) and 0.2 g (with booster) selected after the readings were taken. For all the readings, a turbidity meter was used providing results in Nephelometric Turbidity Units (NTU). Lowest turbidity was achieved when using 5% speed with 0.4 grams of coagulant and 0.4 grams of flocculant, or 5% speed with 0.2 grams of coagulant, 0.2 grams of flocculant and 0.25 g/L of booster coagulant. According to factorial design analysis, such as parameters as impeller speed and dosage have an influential impact on the turbidity; while the booster has insignificant influence and other interactions between parameters are important.

In this work, polysulfone (PSf) mixed matrix membranes were prepared by incorporating modified montmorillonite with lysine amino acid (MMT-Lys) for arsenic removal from water. Different tests including XRD, zeta potential, FE-SEM, contact angle, and pure water ?ux (PWF) were carried out to characterize modified MMT and fabricated mixed matrix membranes. XRD analysis showed that MMT was successfully modified with Lys and its zeta potentials transferred from negative to positive after modification. Positive charge of MMT-Lys made it proper for anionic arsenic removal from water. The obtained results showed that pure water ?ux and surface hydrophilicity of the membranes improved as MMT-Lys contents increased from 0 to 1.5 wt.%. The batch adsorption of fabricated membranes as a function of arsenic initial concentration and solution pH was investigated. The removal ef?ciency was increased with increasing the arsenic initial concentration; however it was decreased with increasing pH of solution. The results also revealed that the arsenic adsorption was most favorable in the neutral pH. Moreover, membrane reusability of the PSf/MMT-Lys (1.5 wt.%) membrane was assessed by conducting ?ve cycles of adsorption-desorption experiments in dead-end ?ltration. The obtained results showed the applicability of the prepared membrane for multiple cycles.

Green preparation of heavy metal saponin complexes has been successfully optimized by direct combination between crude extract of Olea Europaea and Citrus Aurantium with divalent heavy metals, Pb2+ and Cd2+. The main operating factors affecting preparation process were investigated and evaluated in terms of setting time, heavy metal ion concentration, crude extract concentration, and pH value of the medium. Saponin complexes had been prepared using the optimum concentrations of heavy metal ions (120 ppm) and optimum concentration of crude extract (600 ppm) in the slightly alkaline medium. The presence of saponin in plants was confirmed by chemical tests and UV/Vis analysis. Amount of prepared saponine complexes has the order: (Pb/Olive) > (Cd/Olive) > (Pb/Citrus) > (Cd/Citrus). In this process, saponins was isolated and heavy metals were eliminated by a simple, faster and without a huge amount of solvents. The process itself seems to be green isolation of saponins from plants, green removal of heavy metal from aqueous waste streams or green preparation of heavy metal saponin complexes. The process exhibits several advantages and hence benefits, among of them are shorter setting time, higher volume reduction factor and no chemical or solvents used. Direct combination between heavy metals solution and plant extract solution to prepare saponin complex could be considered three in one process. During preparation of the complex, saponin isolated or extracted by heavy metals and the heavy metal eliminated or removed by saponin solution.

In this research, a simple and fast method was employed to synthesize CuO nanoleaves/silica gel nanocomposites (CuO/SGn), which is a cost effective antimicrobial material. CuSO4.5H2O is the only raw material used in CuO/SGn production through the molten salt method. The structure and morphology of the nanocomposites were characterized by DRS, XRD, and SEM. The copper size in CuO/SG was found to be dependent on the immersion time in molten salt. SEM images revealed smaller-sized particle leaves, from a sample obtained after longer immersion time. The antimicrobial activity of CuO/SGn was investigated against Escherichia coli. The produced CuO/SGn showed the inhibitory effect against E. coli. However, the growth-inhibitory effect depends on the copper content and size. Lower loading of CuO nanoparticles in 10 min immersion time resulted in less antibacterial activity (73.33%) and the sample obtained from longer immersion time demonstrated higher antibacterial activity (up to 99.96%). The maximum amount of released Cu ions from nanocomposites produced in 90 min was 12.2 ppm after 6 h. Furthermore, the minimum release of Cu ions was observed by 3 h for 40 min nanocomposite.

Although dyes are widely used in textile industries, they are carcinogenic, teratogenic and mutagenic. Industries discharge their wastewater containing a variety of colors into water resources and make harmful effect on the environment. The present study aims to Evaluate removal of reactive red 198 by nanoparticle zero-valent iron (NZVI) in the presence of hydrogen peroxide from aqueous solution. The effective parameters on the removal of dye such as the hydrogen peroxide concentration of NZVI, contact time, pH and dye concentration were investigated and optimized. According to the results, the combination of NZVI with hydrogen peroxide is more effective than single hydrogen peroxide. At pH = 4, contact time= 40 min, 200 M of hydrogen peroxide, dye concentration= 75 mg/L and concentration of NZVI 2g/L, color removal was achieved 91% approximately. Based on the results of experiments, using hydrogen peroxide- NZVI has high efficiency in removal of azo dye type.