Nitrate Removal from Waste-Water Using Silica Nanoparticles

Abstract

This work presented the removal of nitrate ions in aqueous solution based on silica nanoparticles (SiNPs), which were extracted from rice husk ash. The optimal conditions for nitrate ion adsorption were studied including pH, contact time, adsorbate concentration, and amount of absorbance. The surface morphological analysis showed that the SiNPs extracted (purity of 98%) were around 50 nm with a surface area of 30 m2·g−1 and adsorption average pore width of 2.72 nm, offers possibility for high capability of nitrate ion removal. The experimental results showed that the nitrate ion capability of adsorption was obtained around 14.22 mg·g−1 with a concentration range from 0 to 25 mg·L−1 based on optimizing conditions including pH 6, contact time of 50 minutes, and SiNP dosage of 0.15 g vol−1. In addition, nitrate ion removal based on SiNPs will provide considerate benefits such as the reducing costly sample pretreatment steps, less time-consuming, and reliable methods for processing nitrate-polluted water.

Black Tea Waste as Green Adsorbent for Nitrate Removal from Aqueous Solutions

“…The kinetics were examined at various nitrate concentrations, and the isotherms were carried out at different temperatures. The amount of nitrate retained by the adsorbents, q e (mg g −1 ) for all samples was calculated by Equation ( 1) [12][13][14][15]29]:…”

“…Due to their high solubility and nutritional importance for aquatic plants, nitrates are important components of agricultural fertilizers. In order to meet their nutrient needs, plants use nitrates from the soil, and they can build up nitrates in their leaves and stems [ 12 , 13 ]. Nitrates used in chemical fertilizers are highly soluble in water and do not effectively bind to soil particles [ 14 , 15 ].…”

Effective Removal of Phosphate from Waste Water Based on Silica Nanoparticles

“…Tis relatively low adsorption rate of SiNPs can be contributed to the weak difusion of phosphate ions from surface adsorption sites to the bulk SiNPs pore, which is mainly caused by the small pore size of 4.06 nm. In addition, the adsorption kinetics was investigated by utilizing the pseudo-frst-order kinetic model (Equation ( 2)) and the pseudo-second-order kinetic model (Equation ( 3)) as given below [35,36]:…”

“…Ten, the experiment was performed based on the optimum parameters, i.e., pH 7, SiNPs dosage of 0.3 g, and adsorption time of 90 min at room temperature. Ten, the Langmuir (Equation ( 4)) and Freundlich (Equation ( 5)) models were applied to analyze the experimental data, respectively [35,37].…”

Recent Advances on Porous Siliceous Materials Derived from Waste

“…Furthermore, its chemical inertness and insulating features favor the exploitation of SiO 2 in a plethora of technological applications [ 28 , 29 , 30 , 31 , 32 , 33 ]. Among these, SiO 2 is widely applied in nanocomposite formulations (as filler) [ 34 , 35 , 36 ], industrial catalysis (as substrate) [ 37 , 38 , 39 ], wastewater remediation processes (as adsorbent) [ 40 , 41 ], as a building material component [ 42 , 43 ], and in different advanced biomedical applications (e.g., as a drug-carrier system) [ 44 , 45 , 46 ]. At the laboratory scale, the typical precursors of SiO 2 are alkoxysilanes, such as tetraethyl orthosilicate (TEOS), or tetramethyl orthosilicate (TMSO), largely adopted in synthetic protocols following the sol-gel method [ 47 , 48 , 49 ].…”