Removal of Congo red dye from aqueous solutions by a low-cost adsorbent: activated carbon prepared from Aloe vera leaves shell

Background: synthetic dyes have several harmful effects on human health as well as aquatic life. In this study, activated carbon [AV-AC], based on Aloe vera leaf shells, was used as a novel agricultural adsorbent, one that is low-cost and available for the removal of Congo red [CR] as a carcinogenic dye from aqueous solutions

Methods: in the batch system, the influence of different parameters like contact time, pH, adsorbent dosage, and initial CR concentration were examined on the dye removal from liquid medium. The experimental data were fitted by pseudo-first-order and pseudo-second-order kinetics, and also Langmuir and Freundlich isotherms models

Results: the optimum contact time and pH for the uptake of CR were obtained at 20 minutes and acidic pH of 2. The maximum uptake capacity of CR dye by AV-AC was 1850 mg/g. The results showed that the experimental data were well-fitted by the pseudo-second-order kinetic model [R[2] > 0.99] and Freundlich isotherm model [R[2] > 0.99]

Conclusion: according to the results of our study, the AV-AC is a low-cost, non-toxic, and effective adsorbent for the uptake of CR dye from aqueous media

Health impact assessment of short-term exposure to NO[2] in Kermanshah, Iran using AirQ model

Background: Epidemiological studies have illustrated that exposure to atmospheric nitrogen oxides [NO[2]/NO[X]] is responsible for an increased risk of acute or chronic diseases such as cancer. In this study the health risks associated with nitrogen dioxide [NO[2]] were assessed in the city of Kermanshah, the capital of Kermanshah province, Iran

Methods: Data on hourly NO[2] levels that had been measured with the Environ tech model M200 was taken from the Kermanshah Environmental Protection Agency [KEPA]. The AirQ2.2.3 model was used to quantify data based on baseline incidence [BI], relative risk [RR], and attributable proportion [AP]. The number of cases of cardiovascular mortality [CM], acute myocardial infarction [MI], and hospital admissions for chronic obstructive pulmonary diseases [HACOPD] was estimated

Results: The results of the current study show that there were 33, 16, and 13 cases of CM, acute MI, and HACOPD, respectively, attributable to NO[2] exposure. Furthermore, 26.85% of health impacts occurred on days when NO[2] levels did not exceed 40 micro g/m[3]. For every 10 micro g/m3 increase in the NO[2] level, the risk of CM, MI, and HACOPD rose about 0.2%, 0.36%, and 0.38%, respectively

Conclusion: In order to reduce the number of cases of mortality and morbidity caused by exposure to NO[2], several immediate steps should be taken by the government to control emissions from various sources, particularly car exhaust, to reduce the levels of NO[2] in the atmosphere