Feasibility study of nitrate surface absorption by mineral pumice from Nitrate solution on a laboratory scale

The surge in population and imprudent consumption of water resources have created many challenges in securing sufficient water for sustaining human life. To supply part of the water demand for agriculture, the reuse of gray water is recommended. However, many decontamination methods are cost-prohibitive and pose challenges in sludge disposal after purification. The purpose of this research is to evaluate the feasibility of nitrate absorption by a mineral pumice adsorbent from nitrate solutions. The present study was conducted as a two-factor factorial experiment and complete randomized design with three replications. The study involved sampling mineral pumice with diameters of 1 cm, and 5 cm and gradation ranging from 1 to 5 cm over 45 days. The samples were calibrated by spectrophotometric method at a wavelength of 470 nm. Results showed that mineral pumice influenced nitrate absorption from the solution. The amount of nitrate in the control treatment was 0.88 grams per liter on the first day. The highest absorption occurred on the 20th day for the 1 cm soil gradation, resulting in a decrease to 0.62 grams per liter, which indicated 0.36 grams per liter of nitrate absorption. Larger gradations, however, showed the highest absorption on the 30th day. The 5 cm treatments and 1-5 cm gradation showed a reduction (absorption) of 0.19 and 0.27 grams per liter of nitrate, respectively, compared to the control treatment. According to the results, mineral pumice, an economical resource, can be used to absorb nitrate from nitrate solutions. Moreover, the used mineral pumice could find applications as a soil texture modifier or fertilizer in various fields beyond nitrate absorption.