Resumen
Pollutants in the air are an ever-present global phenomenon and managing these is a more strenuous task. In expense to higher fuel efficiency in automotive applications, emissions of nitrogen oxides (NOx) are a mounting concern as more demanding emission standards are being proposed worldwide. NOx is the reddish-brown layer in the urban air that contributes to the formation of harmful ground level ozone and acid rain. This study was conducted to investigate how NOx emission can be sequestered and reduced using a copper-loaded zeolite reinforced with gypsum (G-CuZC). The zeolite matrix was modified to improve selectivity to NOx through copper-loading via wet ion exchange; its porous structure and high surface area provided the needed active sites. The composite was tested according to its catalytic activity with NOx and the possibility of being sustainably regenerated when conveyed in an emissions control device (ECD). The emission test presented a peak of 3.60% NOx reduction by using a 70:30 (by weight) gypsum to copper-loaded zeolite composite. Scanning electron microscopy imaging showed that surface morphology was a factor in the increase reduction as the G-CuZC had a wider distribution of zeolite compared to its non-copper loaded counterpart, thus having a higher surface area exposed for selective reduction. Increased copper content also increased the NOx reduction as its affinity dictates. This decrease has been noted without the aid of any reducing agents although the hydrocarbons from the exhaust emission during the combustion process may have helped in the performance of the composite. The ordinary citizen, with his attention focused on making a decent living, cannot be expected to easily replace his vehicle just so to adhere to air regulations. It is hoped that an efficient ECD that utilizes a low-cost solid sorbent will provide people with an alternative solution to effectively control vehicular emissions.