[Mechanism and removal efficiency of C.I. acid blake 1 by pumice stone adsorbent]

Treatment of colored wastewater is one of the important challenges of environmental engineers. Adsorption process is a key option for removal of organic matter from wastewater. The aim of present work was to investigate pumice stone as an adsorbent for removal of Acid Black 1 from aqueous solution. Removal of Acid Black 1 by pumice stone was investigated. Acid Hyrdo Chloric[HCL] 1 N was used to increse adsorbent porosity. Various parameters such as pH, initial dye concentration and contact time were studied. Results showed that removal of Acid Black 1 was increased by increasing of contact time and initial dyeconcentration although it was decreased by increasing of pH. Experimental data was best fitted to Longmuir isotherm model [r2>0.98]. Study of diffusion model revealed that intraparticle diffusion is rate-controlling step in removal of Acid Black 1 by pumice stone. The results indicated that pumice stone was a dominant adsorbent for Acid Black 1 removal

Removal of cyanide from aquatic solution by using of iron and copper powder: equilibrium and kinetic study

Industrial wastewater included the cyanide is one of the important sources of environmental pollution which founded in Industrial wastewater which are harmful for human health and environment. Therefore, the purpose of this research that was fundamental designed is investigation of Removal of cyanide from aquatic solution by using of iron and copper powder in experimental scale. At first, pilot was designed. Then, acquired pH optimum equal to 2,7 for copper and iron by variation pH= [2,4,6,8,12] and constant other parameters. The effect of initial cyanide concentration [40,60,80 mg/1], initial iron and copper dosage [0.08-1 g/100CC] and contact time [15-12 min] studied at the constant of optimum pH. The result showed removal efficiency Increased from 46.6% to 90.56% and 31% to 93.78% for copper and iron by increasing of contact time from 15 to 120 minute in constant conditions, respectively. Also result showed Removal efficiency decreased and increased by increasing initial cyanide concentration and initial iron and copper dosage. The results showed equilibrium data were explained acceptably by Langmuir isotherms and kinetic parameters were obtained by application of Langmuir and Hinshelwood equation. The results showed that removal of cyanide can be quick and effective done by iron and copper in experimental scale

[Removal of excess fluoride from water plants by poly aluminum chloride as a new coagulant]

The fluoride ions are commonly found in water resources. These ions should be in optimum levels for prevention of dental caries. However, the excess value can cause such health problems as fluorosis. The aim of the present study was to investigate the removal of excess fluoride ions by using poly aluminum chloride as a new coagulant that is used in water treatment plants. All experiments were conducted in batch system. Several combinations of parameters such as initial fluoride concentration [1.4, 2 and 2.4 mg/L], pH of solution [3, 7, 9], poly aluminum concentration [10, 20, 30, 40 mg/L], and exposure time [30, 60, 90 minute] were investigated. Various concentrations of poly aluminum chloride solution at different pH levels were added into 200 ml of fluoride solution, and samples were taken in predetermined time intervals and the final concentration of fluoride was determined by spectrophotometer at 570 nm. The results showed that, the highest removal was obtained at pH=7. In addition, it was observed that fluoride removal efficiency was higher in pH=5 than in pH=9. Also the results showed that, removal efficacy can be increased by increasing the poly aluminum chloride and the exposure-time. This study denoted that removal of high levels of fluoride ions can effectively be done by using poly aluminum chloride as a new coagulant. Its use is possible in water treatment facilities without any need for modification in water treatment plans

[ clinical and radiographic study of forced eruption technique in treatment of defects in coronal one-third of the root]

Introduction: restoration of defects in coronal one-third of the root is difficult. Forced eruption is a procedure for treatment of these defects. The purpose of this study was to evaluate clinical and radiographic aspects of this technique suggested by Simon

Materials and Methods: in this study 12 patients with defects in coronal one-third of the root were selected and treated. The defects of the selected teeth were caries [2 patients], accidental perforation [1 patient] and root fracture [9 patients]

Result: the clinical and radiographic results of this study showed that forced eruption technique suggested by Simon was successful in all patients

Conclusion: according to the above findings, this technique can be used in treatment of defects in coronal one-third of the root