[Efficiency of Pistaciaatlantica seed extract as natural coagulant in the removal of Reactive Red 198 dye from aqueous solution]

Textile dyes and other dyes used in various industries are among the largest organic compounds which can be a major hazard to the health and environment. Therefore treatment of wastewater before discharging it into the environment is necessary. In the present study we investigated the efficiency of Pistacia atlantica seed extract in a batch system for removal of Reactive Red-198 dye from aqueous solutions. This is a basic- applications study conducted in laboratory. The effects of independent variables such as coagulant dose [0.1-1 ml L-1], initial dye concentration [50, 100, 150 and 200 mg/l] and pH [2-12] were investigated. To measure the residual concentration of dye we used a spectrophotometer at the wavelength of 520 nm. Excel software was used for data analysis. The optimum pH for Reactive Red-198 removal by coagulation using Pistacia atlantica seed extract was 12, with a coagulant dose of 0.5 ml/L. The highest removal rates were 83.12, 84.20, 87.36 and 88.49% at initial dye concentrations of 50, 100, 150 and 200 mg/L respectively, which could be result of precipitation, co-precipitation and adsorption mechanisms. According to the results of this study, Pistacia atlantica seed extract was an inexpensive coagulant, and also quite effective in the removal of Reactive Red-198 dye from aqueous environments

[Optimum operating conditions in the phytoremediation of contaminated soils with Lead and Cadmium by native plants of Iran]

In recent decade, phytoremediation technology is regarded very important because of its simplicity, inexpensiveness and use of natural resources and solar energy. In this study, we investigated the efficiency of remediation of contaminated soil with Lead and Cadmium by using native plants of Iran. We selected three native plants of Iran [Abutilon theophrasti, Amaranthus retoflexus and Zea maize] for this study. Extraction of soil and plant samples was performed by use of HNO3 ,HCl and HNO3, HClO4 and H2SO4 respectively. Concentrations of Lead and Cadmium in soil and plants were determined by Perkin-Elmer 603 atomic absorption spectrophotometer. Lead concentration in the roots of plants [Alkaline soil] was more than those in their shoots. In acidic soil [with exception of Zea maize], concentration of Lead in the shoots was more than its concentration in the roots of the plants. Concentrations of lead in the roots and shoots of Abutilon theophrasti, Amaranths and Zea maize in alkaline soil were [54.5 and 25.5 mg/kg], [69 and 37.6mg/kg] and [47 and 32mg/kg] respectively, and its respective concentrations in acidic soil were [71.4 and 92.5 mg/kg], [89 and 120.5mg/kg] and [85 and 66.7 mg/kg]. Cadmium concentrations in alkaline soil were [6.5 and 4mg/kg], [8 and 6.2 mg/kg] and [5.6 and 3.4 mg/kg] and in acidic soil were [5.8 and 4.5 mg/kg], [7.6 and 5.4mg/ kg] and [6 and 4.8 mg/kg] respectively. Plants in group 3 produced less biomass than those in control group, group 1 and group 2. Considering the increased rate of absorption of Lead and Cadmium and the amount of biomass produced by Zea maize and Amaranthus retoflexus in the acidic and alkaline soil, use of these native plants is recommended for refining the soil contaminated with heavy metals

Control of disinfection by products formation potential by enhanced coagulation

Jar-test experiments were conducted to study enhanced coagulation effectiveness in removal of disinfection by products [DBPs] from Zayandehrud River at Isfahan Province-the center part of Iran- in 2004. In this study, the removal of suspended and colloidal particles and natural organic matter [NOM] at various coagulant doses and coagulation pHs was assessed through raw and treated water measurements of turbidity, UV254 absorbance, TOC, and dissolved organic carbon [DOC]. The trihalomethane formation potential [THMFP] was also determined by a mathematical relationship with TOC. Results indicated that NOM removal was a function of coagulant type, coagulant dose, and pH of coagulation. In general, TOC, DOC, and UV254 absorbance removal enhanced with increasing coagulant dose. However, further increases in coagulant dosage had little effect on disinfection by-products precursors removal. Ferric chloride was consistently more effective than alum in removing NOM. Coagulation pH was appeared to be a determining factor for maximum NOM removal and the removal of DBPs precursors by enhanced coagulation was significantly enhanced at pH 5.5 in comparison with initial pH of water. Furthermore, it is specified that preadjustment of pH with sulfuric acid reduced the coagulant dosage and thus, production of sludge. The reduction in THMFP was consistent with the trends observed for DBPs precursors removal data [i.e. UV254 and TOC data]

Study of heavy metals in urban runoff

A cross-sectional survey was conducted through Tehran city and a field study was conducted to prepare main and accessory drainage channels map. Three main drainage channels were identified for this research and some sampling stations were chosen. Three stations selected in south of Tehran. The reason for selecting these stations is that all urban surface runoff completely pass through these points and samples taken from these points are representative of all kinds of pollutants that transit from city surface. Another Three stations were selected in center and further three stations were selected at north of Tehran. Surface runoff flow in three main channels, from north to south of Tehran, converge at south of Rey city and finally end up to Ghom Salt lake. The stations were chosen at three trajectories, Sorkhe Hesar, Emad Avard, Kan. At each month two samples were prepared from nine different stations. After collection of samples with respect to standard methods, they were dissolved in nitric acid and then analyzed by atomic absorption device. The results show that the concentrations of pollutants increased from north to south. For instance, Zinc had most concentration with monthly average of 0.98 mg/l and Nickel had the lowest amount with 0.02 mg/l in southern stations. Average concentration of Zn, Pb, Cd, Cu and Ni were: 0.638, 0.097, 0.04 and 0.035 mg/l respectively. Total average concentrations of heavy metals at three main channels were of 0.177, 0.176 and 0.145 mg/l. Emad Avard was the most polluted channel