Response surface methodology approach to the optimization of oil hydrocarbon polluted soil remediation using enhanced soil washing

One of the environmental concerns in recent decades is the prevalence of different pollutants in soil. Hence, the importance of remediation has led to the development of various methods to remediate polluted soil. Among these methods, soil washing has gained significant attention to treat polluted soils. In this paper, the response surface methodology was applied in order to determine the optimal conditions for total petroleum hydrocarbon remediation using nonionic surfactant Brij35 in soil environment. The effect of different factors in soil washing process including surfactant solution concentration and volume, washing time, age of pollution and frequency of washing are evaluated. The predicted values for total petroleum hydrocarbon remediation efficiency by the response functions are in a very close agreement with experimental data [R[-2] = 98.75%]. The second order model was developed as experimented response and optimal conditions were obtained by analyzing the contour and surface plots and also by solving the regression equation using LINGO 9.0 software. The optimal concentrations [8 g/L], volume of surfactant solution [500 mL], washing time [75 min], age of pollution [29 days] and frequency of washing [three times] are determined. In this optimal condition, the removal efficiency has been observed to be 93.54% which conforms to the results of process optimization using response surface methodology. Based on the results, it can be concluded that the response surface methodology is a suitable approach to determine the optimal conditions of soil washing to remediate organic hydrophobic pollutants using the nonionic surfactant Brij35 from the soil

Decolorization of an acidic dye from synthetic wastewater by sludge of water treatment plant

In this research, sludge of Jalaliyeh water treatment plant in Tehran was used as an alternative coagulant for the removal of a specific type of acid dye [acid red 119 [AR119]]. For this purpose, the effect of initial pH, coagulant dose and initial dye concentration on dye removal efficiency were investigated. Results showed that the dye removal rates were largely dependent on pH. When the solution pH was increased from 3 to 8, the dye removal rates decreased from 96.3% to 2.3%. The removal efficiencies of the dye using 130-350 mg dried sludge/L were more than 90% at initial pH =3. With the increase of initial dye concentration in the range of 10-200 mg/L, the removal efficiency increased at first [from 10-40 mg/L] and then declined. So, sludge of Jalaliyeh water treatment plant may be considered as an appropriate coagulant for the removal of AR119 dye

[Effect of hydrostatic pressure on PC12 cell line]

The present study was designed to investigate the effect of hydrostatic pressure on cell viability, apoptosis induction, morphology and cell-substrate interactions of PC 12 cells. PC 12 as a neuronal cell line maintained in RPMI 1640 culture medium supplemented with 10% fetal bovine serum. PC 12 cells were subjected to hydrostatic pressure. Experimental pressure condition was 100mmHg set above atmospheric pressure for 2 h. Controls were treated identically except for the application of pressure. Dye exclusion was used for viability assay, TUNEL staining was used for apoptosis detection. Cell area was assessed as morphometry and then cell adhesion, extension and migration were investigated. Hydrostatic pressure had not changed viability of cells. It induced apoptosis in PC 12 cells. In addition, hydrostatic pressure reduced cell area, adhesion, extension and migration ability of these cells [P<0.05]. Hydrostatic pressure may induce apoptosis in PC 12 cells as a result of inappropriate cell to substrate adhesion. Thus it is suggest that occurring apoptosis in these cells be an anoikis cell death induced by loss of attachment to the substrate

Investigation of apoptosis induction in differentiated PC-12 cells after exposure to hydrostatic pressure

Hydrostatic pressure is crucial component of cell environment and fundamental physical quantity, also it is the main factor of both cell integrity and function. Pressure variation disorder, beyond physiological limits, may lead to pathological states. In this study, we examined the effect of hydrostatic pressure on apoptosis induction, viability, morphology, adhesion potency to substrate and migration of differentiated PC-12 cells. PC-12 as a neuronal cell line maintained in RPMI 1640 culture medium supplemented with 10% fetal bovine serum. Staurosporine was used for differentiating of mitotic PC-12 cells to post mitotic and differentiated neuronal cells. Exclusion Dye was used for viability assay, total neurite length of each cell as well as morphometry. TUNEL staining was also performed for apoptosis detection, adhesion potency of cells to substrate and evaluation of cell migration. Hydrostatic pressure, over physiological limits, induced apoptosis in differentiated PC-12 cells. It changed cell viability gradually and reduction happened significantly after 24 hours [p < 0.05]. In compare to the control group, hydrostatic pressure reduced total neurite length, adhesion potency to substrate and migration of cells in the examined group [p < 0.05]. Hydrostatic pressure induced apoptosis in differentiated PC-12 cells as a result of inappropriate interaction between cells and substrate. We propose that apoptosis in differentiated PC-12 cells may be an anoikis causing to lose the attachment to the substrate