ABSTRACT
Background: Discharge of colored sewages, resulting from domestic and industrial wastewaters, results in eutrophication, coloring and hypoxia of waters. Furthermore, colors have mutagenic and carcinogenic effects. This study aimed to investigate the removal rate of acid black 1 dye from aqueous solution using nano-iron particles.
Materials and methods: This study was done experimentally and discontinuously in lab scale. The effect of variables such as contact duration [30, 60, 90, 120, 150 and 180 min], pH [3, 7 and 11], adsorbent dose [0.4, 0.8, 1.2 and 1.6 g/200ml] and dye concentration [50, 150 and 200 mg/l] were evaluated on the removal rate of dye from aqueous solution. The data were analyzed using Excel software.
Results: The results showed that with increase in contact duration, the removal efficiency of dye also increased from 92.85 percent to 99.17 percent. Also, the increase in adsorbent concentration resulted in increase in removal efficiency of dye from 62.11 percent to 99.1 percent. A decrease in pH and dye concentration also increased removal efficiency of dye from 53.71 percent to 99 percent, and from 99.97 to 100 percent, respectively. The results of isothermal study showed that the removal of acid black 1 dye from aqueous solution follows from the Langmuir equation [0.999
Conclusion: According to the results obtained, on an equal condition, nano-iron particles are more efficient than other adsorbents in the removal of dye from aqueous solution; hence these nano-particles are suggested for removal of dyes from polluted waters.
ABSTRACT
Significant left main coronary artery stenosis jeopardizes the entire myocardium of the left ventricle and has the worst prognosis of any form of coronary artery disease. Coronary-artery bypass grafting [CABG] has been considered as the standard therapeutic approach for such patients. There are limited data on the safety and effectiveness of percutaneous coronary intervention [PCI] in patients with unprotected left main coronary artery disease. In this study we have reported our experience on early, intermediate and long term results of LMC intervention. From Dec. 2007 to Mar. 2012, PCI with drug eluted stent [DES] or in some cases by a bare stent was performed on denovo lesions of unprotected left main coronary artery in 50 patients. The inclusion criteria were: patients having refused CABG but with favorable anatomy for stenting; patients with poor general condition or comorbidity whom were refused by the cardiac surgeon and emergent patients for whom CABG was not accessible. The angiographic and procedural success rate was 100%. Four patients died, two because of severe heart failure, the third due to noncardiac etiology, and the fourth due to probable stent thrombosis. We have one target lesion revascularization [TLR=2%] and no reinfarction was occurred. Routine DES implantation in unprotected left main disease seems a feasible and safe method with favorable outcomes