[Study of eggshell performance as a natural sorbent for the removal of reactive red 198 dye from aqueous solution]

Dye compounds is one of the most critical contaminant for natural ecosystems. The aim of this study were to determine the primary concentrations of reactive red 198 dye [RR 198], adsorbent dosage and pH influences for the adsorption of RR 198 onto chicken's eggshell [ES] as an adsorbent. The target adsorbent was prepared in laboratory conditions and pulverized by ASTM standard sieves. Surface characteristics and measurement of the adsorbent surface area was carried out with Scanning electronic microscope [SEM] and via N2 gas adsorption with Brunauer-Emmett-Teller isotherm. The maximum absorption wave length of this dye [lamda-max] was determined by spectrophotometer [Optima SP-3000 Plus]. Analysis of absorption spectra showed that the lamda-max of RR198 is 518 nm. The results show the Calcium components are the main constituent of ES with 1.2 m[2]/g. Elevation of the ES dose [2 to3 g] lead to increasing of dye removal from 80% to 92%. The results show that elevation of pH from 4 to 10 would lead to increasing of RR 198 adsorption from 44% to 64% but increasing of preliminary dye concentration would lead to decreasing of dye adsorption from 72% to 23%. The kinetic studies revealed that the adsorption of RR 198 is rapid and complying with second-order kinetic [R2=0.995] which the kinetic constant is 0.0004min-1. Eggshell is a cheap adsorbent that can be used for the removal of dye components from alkaline solutions

Application of ozonation on the removal of reactive red 198 dye at alkaline condition

Dyes are the most important pollutants of textile industries which have complex structures as well as toxic, carcinogenic, teratogenic and nonbiodegredable properties. This research was performed to compare the efficacy of removal and mineralization of Reactive Red 198 dye at alkaline and neutral pH. The effect of different pH: 7,9,10 and 11 in dye and COD removal from 250 mg/1 aqueous solution of RR198 was evaluated. Dye removal efficiency was measured by UV-vis spectrophotometer and data were analyzed using SPSS 16, via statistical tests including One-Way ANOVA. COD removal efficiency was also measured by closed reflex method. Dye removal efficiency was higher than 96% in all different types of pH and also showed significant difference in different time intervals [P<0.05]. COD removal was lower than dye removal and in different types of pH: 7, 9, 10 and 11 which after 60 minutes of reaction reached to 31, 40, 43 and 53% respectively. From the collected data it is obvious that rapid dye removal is due to the reaction of both molecular ozone and free radicals with dye molecules but more COD was removed only after the generation of hydroxyl radicals via pH elevation

[ effect of psychosocial supportive interventions on PTSD symptoms after Bam earthquake]

Many studies have shown the efficacy of cognitive' behavioral therapy and psychological debriefing in treatment of post traumatic stress disorder [PTSD] and a few evidences are available for using these techniques in large scale disasters. This study aimed to asses the effect of some psychological interventions in reducing PTSD symptoms after Bam earthquake in different age groups. In a before-after quasi experimental clinical trial, we compared the efficacy of one session of psychological debriefing and three sessions of group cognitive-behavioral therapy in bam earthquake PTSD symptoms in different age groups. We evaluated PTSD symptoms before and immediately and three months after interventions by CASP scaling system and analyzed data. one hundred and thirty persons entered in the study and 51 persons excluded during interventions because of migration. Interventions were showed to be effective only in short term period. The means of PTSD symptoms frequency and severity of avoidance symptoms were reduced during three months period of study which were statistically significant P<0.05. Interventions showed no efficacy for recall symptoms in long term and hyper arousal symptoms in short term and long term periods. There was no statistically significant difference among age groups. Psychosocial supportive interventions may be effective on some of the PTSD symptoms but there is no difference in different age groups