فهرست مطالب لاله دیوبند

In recent years, concerns about the long-term effects of heavy metals as one of the main environmental pollutants has increased. These metals have adverse effects on human health, which include growth retardation, cancer, damage to the nervous and heart system. Mainly heavy metals discharge into environment from industrial and urban sewage. There are the different methods to reduce water pollution and removal of heavy metals from water.There are the different methods to reduce water pollution and removal of heavy metals from water that one of them is adsorption by using organic and inorganic absorbers. In this study, the use of nanoclay (Cloisite Na) for adsorption of chromium form Single- and two- component solution (competitive) was investigated.
this study was conducted in scale laboratory conditions and batch system by changing the factors that affect the absorption process such as pH (2-10), contact time (5-1440 minutes), adsorbent dose (1- 5 and 2 gr/L) and adsorbate concentration (1-100 mg/ L). Then in solution of single and two elements systems, experimental data were investigated with absorption isotherms of Freundlich, Langmuir and Sips.
Results showed that the optimum pH values for adsorption of chromium were 6 and 7 for single-element and two elements systems, respectively. Also, in single and two-element systems, the maximum removal efficiency was obtained (82% and 59.2%). Effect of contact time on the adsorption process showed that equilibrium time of removal of Cr (VI) by nanoclay (Cloisite Na) is 180 min in single element systems and 240 min in two-element systems. Optimum dosage of adsorbent for absorption of chromium ions from single and two element solution with a concentration of 10 ppm is 5 and 20 g/L, respectively. Comparison of the Freundlich, Langmuir and Sips isotherms showed that the Sips model for single element system was described data of adsorption better than other models with R2 (0.9977) and RMSE (0.1751). Also in two-element system, Freundlich model with R2 (0.9721) and RMSE (0.2831), is better fit with data of adsorption.
Due to the presence of heavy metals in various industries wastewater and their effects on adsorption of each other by the different adsorbent, it is necessary for getting real results in the process of adsorption Notice to this matter. The results of this study also showed that the absorption presses of chromium from solutions of single element or combination of elements with the same adsorbent are completely different.

Heavy metals in water resources are one of the most important environmental problems in most of countries. Up to now, various methods for removing these metals including using low price materials have been used. In this study, two new absorbents (zizyphus spinachristi leaf and its fly ash) were studied for adsorption of cadmium from aqueous solutions using batch experiments. The effect of contact time, pH, and amount of adsorbent on adsorption efficiency was evaluated and the best kinetic and isotherm model was determined. Results showed that optimal absorption of pH was 5 and 6 for zizyphus spinachristi leaf and its fly ash, respectively. The equilibrium time was 45 min for zizyphus spinachristi leaf and 30 min for ash. Adsorption efficiency was increased by increasing the adsorbent dose. By comparing the parameters of isotherm models, it was observed that the cadmium adsorption capacity of fly ash (4.27 mg/gr) was higher than that of zizyphus spinachristi (3.91 mg/gr).

Removal of toxic heavy metals from wastewater is an important environmental challenge. In this work, the nano particle of zizyphus spinachristi fly ash is used as a fit adsorbent for the removal of Zn2 from aqueous solutions and industrial wastewaters. Bath experiments were used to determine the best adsorption conditions. The experiment showed that the adsorption capacity of nano particle of zizyphus spinachristi fly ash is a function of pH, contact time, amount of adsorbent and initial concentration in solution. Maximum adsorption of Zn2 was obtained at pH of 5, contact time 30 min, amount of adsorbent 20 g/L and initial concentration of 2 mg/L. The Ho et al. and Lagergern kinetic models were used to determine the correlation among the experimental data. The correlation coefficients obtained for Ho et al. (R2= 0.9979) and Lagergern)R2=0.9925) models showed that the Lagergern model described better the experimental data. Metal adsorption onto adsorbent was evaluated by Langmuir and Freundlich isotherms. Results indicated. the Langmuir isotherm model(0.9645) is the most suitable one for the adsorption process using sheep gut waste.

Existence of Heavy metals in water resources is one of the most important environmental problems in many countries. These metals have dangerous effects on human health. The purpose of this study is to investigate and compare lead removal by nanometer and millimeter absorbents of Zizyphus Spinachristi fly ash. This study was non-continuous experiment which was implemented under laboratory conditions with and by changing effective factors such as pH (3، 4، 5، 6، 7، 8)، contact time (5، 10، 15، 30، 45، 60، 90، 120 minutes) and adsorbent concentration (1، 2، 5، 10، 20 and 50 mg/ L). The data was fitted based on four models including Ho et al، Lagergern، Lungmuir and Freundlich which the first two models used for absorption kinetic and the latter two considered as absorption isotherm. The Result of this study showed that as the pH increases from 3 to 5 adsorption efficiency increased as well. Furthermore، when pH was over 5، the metal ions settled down. With increasing contact time، adsorption efficiency increased as well. With increasing the amount of nanometer as an adsorbent، removal efficiency increased and then decreased. Also the adsorption process followed precisely Ho et al kinetic and Langmuir isotherm، for both absorbents. Based on the obtained results، specific area of the nano particles was more than millimeter particles (29. 56 m2/g & 17. 80 m2/g)، therefore adsorption capacity of nano absorbent was four times more than adsorption capacity of millimeter (19. 93 mg/g & 17. 80 mgr/g). Furthermore، the findings concluded high capability of nano particles towards Sorption of lead ions (Pb) from aqueous solutions.