RESUMO
Introduction: Countries around the world are looking for an appropriate, stable, and affordable replacement for the natural energies. Therefore, the waste is considered as an available resource to produce energy, which by controlling, its effects on the environment could be minimized
Materials and Methods: To conduct this review article, the scientific data related to the topic were gathered from scientific databases such as Google Scholar, PubMed, Elsevier, Scopus, Springer, Magiran, and SID using waste to energy, Biogas, Incinerator, Landfill, and Pyrolysis as the keywords. In addition, 53 articles were used for this research [from 1993 until 2016]
Results: The results indicated that from a technical point of view, according to Iran's current environment and the properties of the produced waste, most methods mentioned in the study are applicable. However, the important issue is to choose the best technologies with the best functionality in Iran, based on the composition of the municipal solid waste, proved technologies, and the municipal solid waste management strategies
Conclusion: This study recommends construction of incineration plants with an appropriate location for processing municipal, household, and industrial hazardous wastes, as well as energy recovery. In addition, promoting application of household biogas reservoirs in villages and use of pyrolysis for some industries to converse industrial waste into fuel, are further suggested
RESUMO
Background: Co[II] constitutes a part of vitamin B12, hence, it is necessary for human health. However, at concentrations higher than the permissible limits, humans and animals suffer adverse chronic effects. It is necessary to reduce the concentration to a permissible level. In the present study, pre-purification and thermal modification of chicken's feather increased their porosity and they were used to adsorb Co[II] ions from aqueous solutions
Methods: Chicken feather was procured from a slaughter house, washed with detergent and dried at laboratory temperature. To increase the porosity and remove the organic pollutants attached to the feather, feathers were heated in the oven for 1 hour at 165 degree C. Some batch experiments were conducted to optimize the parameters affecting the adsorption process, such as solution pH, initial concentration of Co[II] and contact time, at a constant agitating speed and temperature
Results: The pH[zpc] of chicken's feather granules obtained was 5.3. The results showed that a time of 60 minutes, pH value of 9 and initial concentration of 10 mg/l were the optimum conditions for Co[II] removal by the adsorption process. Increasing the initial concentration of Co[II] from 10 to 50 decreased the removal efficiency from 52% to 26%. The pseudo-first order kinetic model provided the best correlation [R[2] = 0.998] for adsorption of Co[II] on chicken's feather granules
Conclusion: The increase in electrostatic repulsion forces between positive charges of Co[II] ions decreased the removal efficiency at higher concentrations of Co[II] ions. The maximum efficiency of Co[II] adsorption was obtained at pH= 9, which is higher than the pH[zpc] of the adsorbent