Role of Public Awareness Ensuring the Sustainability of Arsenic Mitigation

Arsenic poisoning is the largest mass poisoning in history. It causes numerous toxic effects to human health which ultimately leads to cancer or Alzheimer’s disease. Nearly 300 million people over 180 countries worldwide are suffering from the arsenic contaminated groundwater more than WHO directed limit. Despite of its potential fatal toxicities, there is no effective treatment for arsenicosis. Cost-effective arsenic removal technology is also a matter of considerable research. This study aimed to summarize the individual and social issues related to arsenic problem and the remedies suggested by different authors to cope with the adverse effects of arsenic. Reported studies emphasized that only mass awareness and mass education can stop the spreading of this disaster. This study will be helpful for future research on the awareness on arsenic contamination and studies on assessing behavior in different context. Policymakers may find it as helpful resource since it describes the problem from grass-roots level. Researchers’ of pharmaceuticals and medicines may be inspired to perform their research in this field.

Study on the Removal Efficiency of Heavy Metals in Flue Gas of Small Sintering Machines

Heavy metal pollutants such as Hg, Pb, Cr, and Cd contained in flue gas from the sintering equipment bring about environmental hazards. In this paper, 4 small sintering machines with different control technologies were selected, and the US EPA 29 method was used to analyze the emission concentration of heavy metals from the sintering machines, and the removal efficiency of the different flue gas control technologies on the of heavy metal pollutants was analyzed. The results show that the dry flue gas desulfurization combining baghouse dedusting method has high removal efficiency of heavy metals in flue gas, with mercury removal efficiency of 60.06%, Pb removal efficiency of 92.92%, Cd removal efficiency of 92.20%, Cr removal efficiency of 55.14%. The removal efficiency of heavy metals is obviously higher than that of conventional electrostatic precipitation combining wet desulfurization. This is mainly ascribed to those heavy metals are mainly concentrated in the fine particulate matters of the fly ash. Dust removal technology can effectively coordinate the control of Hg, Cr, Pb and Cd in the flue gas. The semi-dry desulphurization and baghouse dedusting technology can promote the enrichment of Hg and Cr in fly ash. The results of this study can provide theoretical guidance for the control of Hg, Cr, Pb, Cd and other heavy metal pollutants control in sintering equipment, and for flue gas ultra-low emission transformation.

Numerical Simulated and Mechanism Research on Fine Particle of Pigsty Removal in the Coupling Effection of Acoustic Wave and Electric Field

For improving the collection efficiency of electrostatic precipitator (EP) in the pigsty, MATLAB & Finite element method (FEM) is applied to calculate RNG k-ε equations, corona equation and acoustic radiation equations to analyze sound field, electric field and particle trajectory in the wire-plate EP. The results show that fine particle agglomeration can be induced, so as to promote the enlargement of fine particles and improve the capture efficiency of fine particles at acoustic node area. Moreover, the particle distribution can be controlled according to the above V-η curve in the pigsty. In addition, η initially increases, and then decreases in the range of f from 1000 Hz to 2000 Hz. Therefore, the linear variation law of V– η & SPL – η & f – η provide scientific control method for the construction of green and efficient removal technology of particulate pollutants in the piggery.

Ammonium Ion Enhanced V2O5-WO3/TiO2 Catalysts for Selective Catalytic Reduction with Ammonia

Selective catalytic reduction (SCR) is the most efficient NOX removal technology, and the vanadium-based catalyst is mainly used in SCR technology. The vanadium-based catalyst showed higher NOX removal performance in the high-temperature range but catalytic efficiency decreased at lower temperatures, following exposure to SOX because of the generation of ammonium sulfate on the catalyst surface. To overcome these limitations, we coated an NH4+ layer on a vanadium-based catalyst. After silane coating the V2O5-WO3/TiO2 catalyst by vapor evaporation, the silanized catalyst was heat treated under NH3 gas. By decomposing the silane on the surface, an NH4+ layer was formed on the catalyst surface through a substitution reaction. We observed high NOX removal efficiency over a wide temperature range by coating an NH4+ layer on a vanadium-based catalyst. This layer shows high proton conductivity, which leads to the reduction of vanadium oxides and tungsten oxide; additionally, the NOX removal performance was improved over a wide temperature range. These findings provide a new mothed to develop SCR catalyst with high efficiency at a wide temperature range.

Effect of Defocused Nanosecond Laser Paint Removal on Mild Steel Substrate in Ambient Atmosphere

The obvious advantages of laser paint removal technology make it a viable alternative to traditional paint removal methods. Infrared nanosecond laser was used to remove paint from car body. The microstructure, composition, surface roughness, hardness and ablative products of the samples were analyzed. The effect of the process combination of laser defocus distance and ambient atmosphere (ambient air, compressed air and inert atmosphere) on the substrate damage and the paint removal effectiveness was explored, and the related mechanism was discussed. Defocus not only changed the fluence of laser spot but also increased the spot diameter. The effect of defocused laser paint removal on the paint and substrate was caused by the superposition of these two factors. The results show that the laser with defocus distance of +4 mm effectively removed the paint in inert atmosphere and has the least adverse effect on the substrate. The content of C element and organic components on the substrate surface was the lowest, and its surface roughness and hardness was very close to the uncoated substrate. Focused laser paint removal in ambient air caused the most serious damage to the substrate. Its surface microhardness increased by 11 HV, and the influence depth reached 37 µm. The mechanism of laser paint removal without auxiliary gas is the superposition of laser plasma effect, laser gasification effect and thermal stress effect. In open atmosphere (compressed air and inert atmosphere), the mechanism of laser paint removal is laser gasification effect and thermal stress effect. This research can provide practical references and theoretical basis for the large-scale industrial application of low/non-damage laser paint removal technology.

Estudios sobre la fitorremediación basada en alga wakame (undaria pinnatifida) en la rizoextracción para remover metales pesados de la zona ribereña de la cuenca del río grande-palpa

In the present study, the algae Undaria pinnatífida has been investigated as a biological adsorbent for the elimination of pollutants from surface waters, specifically heavy metals. Operational parameters were optimized in batch phytoremediation experiments. Adsorption equilibrium isotherm models were also investigated and adsorption kinetics were evaluated. Maximum adsorption capacities were observed at 0.008 mg / L at 0.064 mg / L of Cd and for the second sample the adsorption capacity was calculated at 0.007 mg / L at 0.055 mg / L of Cd both in a time of 24 hours, together With removal efficiencies, they reached 72% and 92.7% for the remediation of the Rio Grande water, respectively. These results are important in the development of zero-cost, algal-based pollutant removal technology in water treatment. En el presente estudio, se ha investigado la algas Undaria pinnatífida, como adsorbente biológico para la eliminación de contaminantes de aguas superficiales, específicamente metales pesados. Los parámetros operativos se optimizaron en experimentos de fitorremediación por lotes. También se investigaron los modelos de isoterma de equilibrio de adsorción y se evaluó la cinética de adsorción. Se observaron capacidades máximas de adsorción en 0.008 mg/L a 0.064 mg / L de Cd y para la segunda muestra la capacidad de adsorción se calculó en 0.007 mg/L a 0.055 mg / L de Cd ambas en un tiempo de 24 horas, junto con las eficiencias de remoción se alcanzaron al 72% y 92.7% para la remediación del agua del río grande, respectivamente. Estos resultados son importantes en el desarrollo de tecnología de eliminación de contaminantes de costo cero basada en algas en el tratamiento de aguas.