Development a Conceptual Framework for Industrial and Hazardous Wastes Rating Systems

Production of a large volume of industrial and hazardous waste with various compositions makes the need for comprehensive management and consequently the concept of waste rating more tangible. Despite numerous waste rating systems presented so far, analyzing the makeup of such systems play a significant role in meeting human health. In this study, the structure of 34 rating systems of industrial and hazardous waste have been analyzed based on both quantitative and qualitative standpoints and the results are presented as a formational-conceptual framework. Results showed that every rating system is formed of two parts of formational fundamentals and functional indices, which the first part has a longitudinal relation with the second. While lowly considered, this study is focusing on the formational fundamental part in the rating systems of industrial and hazardous waste, as intellectual prerequisites in suggesting a new system. Some of the factors in the first level are: dependence of the organization which determines the policy and general goals of a rating system, time of presenting the method during which remarkable changes take place in computing methods of the rating systems, infrastructures and facilities which are efficient in the accuracy and scope of the system and finally references and standards causing variations in definitions and final results of the rating system. Furthermore, factors such as: aspects of the study and style of use are identified in second level of formational fundamentals. Finally, the fundamentals are presented in a formational-conceptual framework for better perceiving and more effective use

Industrial Wastes Risk Ranking with TOPSIS, Multi Criteria Decision Making Method

Today, various types of industrial waste are produced in different industries to meet human demands. Growth in quantity as well as complication in quality of these wastes are followed by the advance of technology. Management of such wastes need a proper identification and comprehensive understanding of the risk, emerging after the harmful characteristics of the wastes and negatively affect the human and environment health. Wastes risk ranking systems, in this regard, links between the industrial wastes indices and mathematical method/algorithm, being able at estimation of the risk level as well as comparison between the wastes of an industrial unit based on the risk level. Complexity of the method, high computational costs and lack of proper description of waste using selected indices in former studies has led to the proposal of an applicable and flexible method. In this study, the “TOPSIS Multi-Criteria Decision-Making (MCDM) method” was developed in order for ranking the risk of various industrial wastes. Totally, a number of 9 subsidiary indices on the human health and 11 subsidiary indices on the environment health was identified and employed. Finally, the proposed waste risk ranking system was used for ranking 9 types of identified industrial waste in three industrial section. Results show that the “TOPSIS MCDM”, due to the lack of complexities in method and limited computational costs, is an efficient and appropriate method for ranking industrial wastes

Synthesis of iron-doped TiO2 for degradation of reactive Orange16

In this study the optimum conditions for preparing the iron-doped TiO(2) nanoparticles were investigated. Samples were synthesized by sol–gel impregnation method. Three effective parameters were optimized using Taguchi method, consisted of: (i) atomic ratios of Fe to Ti; (ii) sintering temperature; (iii) sintering time. The characterization of samples was determined using X-ray diffraction, BET- specific surface area, UV- Vis reflectance spectra (DRS) and scanning electron microscope (SEM). The XRD patterns of the samples indicated the existence of anatase crystal phase in structure. UV- Vis reflectance spectra showed an enhancement in light absorbance in the visible region (wavelength > 400 nm) for iron-doped samples. The photocatalytic activity of samples was investigated by the degradation of RO 16 (RO 16) dye under UV irradiation. The results illustrated that the photocatalytic activity of iron-doped TiO(2) was more than pure TiO(2), because of the smaller crystal size, grater BET surface area and higher light absorption ability

Effect of two prophylaxis methods on adherence of Streptococcus mutans to microfilled composite resin and giomer surfaces

Objectives: Surface attributes of a restoration play an important role in adherence of plaque bacteria. Prophylaxis methods may be involved in modification of or damaging the restoration surface. The aim of the present study was to evaluate the effect of two prophylaxis methods on adherence of Streptococcus mutans to the surface of two restorative materials. Study design: A total of 60 specimens were prepared from each material; a microfilled composite resin (HelioProgress) and a giomer (Beautifil II). For each material, the specimens were randomly divided into three groups (n=20). Group 1: no prophylaxis treatment (control); Group 2: prophylaxis with pumice and rubber cup; Group 3: prophylaxis with air-powder polishing device (APD). The surfaces of selected specimens from each group were evaluated under a scanning electron microscope (SEM), and the surface topography formed by the two prophylaxis methods was determined by atomic force microscopy (AFM). Adherence of Streptococcus mutans to the surface of specimens was determined by the plate counting method following immersion in a bacterial innoculum for 4 hours, rinsing and sonication. Data were analyzed by two-way ANOVA and post hoc Tukey test for multiple comparisons. Statistical significance was set at P<0.05. Results: Bacterial adherence was significantly affected by both factors: restorative material type and prophylaxis method (P<0.0005). Mean bacterial adhesion was significantly higher in composite groups compared to corresponding giomer groups. Within each material, bacterial adherence was significantly lower in the control group compared to prophylaxis groups. Prophylaxis with pumice and rubber cup resulted in a significantly lower bacterial adherence compared to prophylaxis with APD. Conclusions: Based on the results of the present study, giomer specimens demonstrated lower bacterial adherence compared to composite resin specimens. In both materials, the highest bacterial adherence was observed with prophylaxis with APD, pumice and rubber cup and the control group, respectively. © Medicina Oral S. L

Mikrodalga reaktörde buharlı metanol reformlamadan hidrojen üretimi.

Today’s world is facing crucial environmental issues, such as climate change and greenhouse gas emission, mainly attributed to the overusing fossil fuels. An environmentally friendly and sustainable replacement is proton exchange membrane fuel cell system which is a promising technology fed by hydrogen. However, fuel cell’s anode catalyst is sensitive to amount of CO in the feed stream. Steam reforming of methanol is an appropriate method for hydrogen production. Nevertheless, endothermic nature of this reaction brings its economic feasibility into question. In this study, hydrogen was produced from methanol steam reforming (MSR) reaction. For this purpose, metal-loaded mesoporous carbon catalysts were synthesized and characterized. The catalyst activity was tested in the MSR reaction heated by a conventional heating method. Effect of catalyst calcination temperature, Cu/Zn ratio, total metal loading amount, and reaction temperature was investigated on the reaction product distribution, methanol conversion, and hydrogen yield. Furthermore, microwave was used as an alternative heat source which is more efficient than conventional heating method. CMK-3 with the surface area of 1120 m2/g, pore volume of 3.7 cm3/g, and pore size of 3.7 nm was synthesized as the support material. Both support material and metal loaded catalyst exhibited Type IV isotherm with H2 hysteresis. It was observed that the catalyst activity increases with increasing Cu/Zn ratio and total metal loading amount, while increasing the catalyst calcination temperature declines the catalyst activity. CO-free hydrogen was produced from the 18.75Cu6.25Zn/CMK-3/300 catalyst at 250oC in the conventionally-heated reactor system with methanol conversion of 93.0% and hydrogen yield of 94%. A higher methanol conversion was obtained in the microwave-focused heated reactor system compared to the conventionally-heated reactor system in addition to a higher energy efficiency. 97.5% methanol conversion and 95.6% hydrogen yield were achieved in this system at 300oC.M.S. - Master of Scienc

The optimum conditions for synthesis of Fe3O4/ZnO core/shell magnetic nanoparticles for photodegradation of phenol

The photocatalysis of phenol was studied using Fe(3)O(4)/ZnO core/shell magnetic nanoparticles (MNPs). The photocatalysts were synthesized by coating of ZnO onto the magnetite by precipitation method and characterized by XRD, SEM and FTIR measurements. Using the Taguchi method, this study analyzes the effect of parameters such as calcinations time, calcinations temperature and molar ratio of Fe(3)O(4):ZnO on the photo activity of Fe(3)O(4)/ZnO MNPs. XRD and FTIR analysis confirm that coating process was done successfully. SEM images show that the average particle size of synthesized Fe(3)O(4)/ZnO nanoparticles was about 50 nm. The phenol removal efficiency of 88% can be achieved by using a photocatalyst which is synthesized through the optimum conditions: calcinations temperature of 550°C, calcinations time of 2 hours and molar ratio of 1:10 for Fe(3)O(4):ZnO