Effect of TiO2-ZnO/GAC on by-product distribution of CVOCs decomposition in a NTP-assisted catalysis system

In this study, the catalytic effect of TiO2-ZnO/GAC coupled with non-thermal plasma was investigated on the byproducts distribution of decomposition of chlorinated VOCs in gas streams. The effect of specific input energy, and initial gas composition was examined in a corona discharge reactor energized by a high frequency pulsed power supply. Detected by-products for catalytic NTP at 750 J L-1 included CO, CO2, Cl2, trichloroacetaldehyde, as well as trichlorobenzaldehyde with chloroform feeding, while they were dominated by CO, CO2, and lower abundance of trichlorobenzaldehyde and Cl2 with chlorobenzene introduction. Some of the by-products such as O3, NO, NO2, and COCl2 disappeared totally over TiO2-ZnO/GAC. Furthermore, the amount of heavy products such as trichlorobenzaldehyde decreased significantly in favor of small molecules such as CO, CO2, and Cl2 with the hybrid process. The selectivity towards COx soared up to 77 over the catalyst at 750 J L-1 and 100 ppm of chlorobenzene. © by Farshid Ghorbani-Shahna 2015

Enhanced performance of non-thermal plasma coupled with TiO2/GAC for decomposition of chlorinated organic compounds: Influence of a hydrogen-rich substance

Background: No study was found in the literature on the combination of TiO 2 /GAC catalyst and non-thermal plasma for chlorinated volatile organic compounds abatement in air. This paper presents this hybrid process for the decomposition of chloroform (as a target compound) using a multi-pin to plate discharge reactor. The experiments were performed using a high frequency pulsed transformer as the power supply system to examine the effect of SIE, frequency, as well as initial concentration on the chloroform removal efficiency (RE). Toluene was added as a hydrogen-rich source to shift the reactions into the formation of environmentally desirable products. Results: RE of around 60% was observed with the NTP-alone process at the highest possible SIE (3000 J L -1 ), while it rocketed up to 100% (total oxidation) in the presence of TiO 2 /GAC at SIE of 1000 J L -1 . About 100% O 3 destruction over TiO 2 /GAC and both adsorption and catalytic activities of GAC may be considered as the reasons for better performance of the hybrid process. Toluene feeding diminished the chlorinated by-products such as Cl 2 and TCE significantly. The selectivity towards CO 2 was noticed to enhance noticeably, when both catalyst and toluene were introduced, regardless of the input concentration. Conclusions: Our findings suggest that the hybrid of NTP with TiO 2 /GAC will highly be effective in the abatement of chloroform, and the addition of toluene will successfully decline harmful chlorinated by-products. © 2014 Abedi et al., licensee BioMed Central Ltd

The study of water droplets electrical charging effect on spray tower scrubber efficiency for feldspar particles removal

Background and aims: One of the modern ways introduced nowadays for increasing the collection efficiency of particulate, is the use of electric charge in wet scrubbers. These systems can be used in places in which scrubbers are suitable for contaminant collection. In fact, this system only increases the collection efficiency, and it is not a new technology for contaminant collection.   Methods: First, according to ACGIH recommendation for pilot study a ventilation system was designed and installed. Later, water was charged by using an DC electric exchanger (1275 Volt, DC)& product 3×1014 electron on system. Air velocity in the duct was determined by Pitot tube, pressure drop and speed equations, and sampling prop diameter was calculated considering isokenetic conditions. Sampling was performed at two flow rates of 20.3 and 11.4 liter per minute and in overall 72 samples were collected. Sample analysis was performed using gravimetric method and data analysis was performed using SPSS software.      Results: The collection efficiency of inhalable particles in the flow rate of 20.3 liter per minute in a non-electric intervention, and electric intervention with positive and negative charge was 66, 77.67 and 73 percent and in the flow rate of 11.4 liters per minute 60, 69.43 and 68.32 percent respectively. For non-inhalable particles the efficiency in the flow rate 20.3 liter per minute in a non-electric intervention and electric intervention with positive and negative charge was 94.67, 98.33 and 97.67 percent, and in the flow charge of 11/4 liter per minute the flow charge was 91.33, 95, and 97.33 percent respectively.  Conclusion: The results obtained from the experiments, showed that in a certain flow rate, electric intervention increases the efficiency of inhalable particle collection. By the way, this electric intervention has no significant effect on non-inhalable particle collection. Also, the effect of electric intervention with positive chargeis higher than electric intervention with negative charge, and with the increase of water flow rate there is an increase in the collection efficiency of the inhalable and non-inhalable feldspar particles

Introducing a Framework for competency based Selection of Health, Safety and Environment (HSE) Managers

Introduction: In HSE management systems competency has been considered as an important tool for selecting managers and resource allocation. Lack of proper HSE managers can undermine the performance of the management system. On the other hand competent HSE managers can improve the performance of management system and reduce the time to perform activities. This study was aimed to present a model to select the HSE managers. .Material and Method: In this study, similar models were examined to select the basic framework. Model dimensions and weights were determined using the focus group technique. The model was used in a large industrial company. The model was approved by the evaluation of the results and correction of the identified defects. .Result: The approved model included technical, behavior and concept competence. Technical competence for managers in level 1 and 2 and behavior competence for managers in level 3, were the most important dimensions. . Conclusion: HSE managers in various level should have different competencies which can be evaluated by presented model in the current study, before employment and also it can be used as a basis for monitoring individuals during specific period of time

Effect of TiO₂-ZnO/GAC on by-product distribution of CVOCs decomposition in a NTP-assisted catalysis system

In this study, the catalytic effect of TiO2-ZnO/GAC coupled with non-thermal plasma was investigated on the byproducts distribution of decomposition of chlorinated VOCs in gas streams. The effect of specific input energy, and initial gas composition was examined in a corona discharge reactor energized by a high frequency pulsed power supply. Detected by-products for catalytic NTP at 750 J L-1 included CO, CO2, Cl2, trichloroacetaldehyde, as well as trichlorobenzaldehyde with chloroform feeding, while they were dominated by CO, CO2, and lower abundance of trichlorobenzaldehyde and Cl2 with chlorobenzene introduction. Some of the by-products such as O2, NO, NO2, and COCl2 &enspdisappeared totally over TiO2-ZnO/GAC. Furthermore, the amount of heavy products such as trichlorobenzaldehyde decreased significantly in favor of small molecules such as CO, CO2, and Cl2 with the hybrid process. The selectivity towards COx soared up to 77% over the catalyst at 750 J L-1 and 100 ppm of chlorobenzene

Decomposition of chlorinated volatile organic compounds (CVOCs) using NTP coupled with TiO2/GAC, ZnO/GAC, and TiO2-ZnO/GAC in a plasma-assisted catalysis system

No study was found in the literature on the catalytic effect of TiO2/GAC (Granular activated carbon), ZnO/GAC, and TiO2-ZnO/GAC combined with non-thermal plasma (NTP) for the decomposition of chlorinated volatile organic compounds (CVOCs) in gas streams. In the present study, this catalytic NTP process was investigated to examine the effect of specific input energy (SIE), initial concentration, as well as residence time on the removal efficiency (RE) of CVOCs in a corona discharge reactor energized by a high frequency pulsed power supply. A dip-coating sol-gel impregnation technique was used to coat TiO2, ZnO, and mixture of TiO2-ZnO nanoparticles on GAC, which were then combined with NTP in a two-stage configuration. The results revealed that the efficacy of the catalysts was in the order TiO2-ZnO/GACâ� TiO2/GAC>ZnO/GAC with chloroform feeding, while when chlorobenzene introduced, the order changed to TiO2-ZnO/GAC > ZnO/GAC>TiO2/GAC. A significant enhancement was observed with RE as catalysts coupled with NTP in all cases and a RE of 100 was achieved in the presence of both TiO2/GAC and TiO2-ZnO/GAC at SIE of ca. 400JL-1. Considerable improvement was also noticed for coupling TiO2 and ZnO in both efficiency and catalyst life time. © 2014 Elsevier B.V