Introduction of nitrogen doped graphene nanosheets as efficient adsorbents for nitrate removal from aqueous samples

Preparation and application of zeolite-zinc oxide nano composite for nitrate removal from groundwater

Nanomaterial assisted removal of pollutants from water has got great attention. This study aimed to remove nitrate from groundwater using zeolite and zeolite-ZnO nanocomposite as synergetic effect. Zeolite-ZnO nanocomposite was prepared using the co-precipitation method. The Physico-chemical characteristics of the nanomaterials were determined using XRD, SEM, and FTIR. The results revealed that; Zeolite-ZnO nanocomposites with 13.12 nm particle size have successfully been loaded into the zeolite. In addition, its chemical composition was determined using AAS. The removal efficiency of nitrate from groundwater was studied using a batch experiment. The removal of nitrate was investigated as a function of adsorbent dose, pH, initial concentration of nitrate, contact time, and agitation speed. Moreover, the adsorption isotherm and kinetics were also determined. The results showed that the removal of nitrate was 92% at an optimum dose of 0.5 g, pH 5, initial nitrate concentration of 50 mg/L, the contact time of 1 h, and agitation speed of 160 rpm. The removal nitrate has been fitted well by the Langmuir isotherm model with correlation coefficients of R² = 0.988. Thus, indicating the applicability of monolayer coverage of the nitrate ion on the surface of the nanocomposite. The adsorption process follows the pseudo-second-order model with a correlation coefficient of R² = 0.997. The results of this work might find application in remediation of water by removing nitrate to meet the standards of water quality.

Carbon Nanotubes Modified by BiMo Metal Oxides for Oxidative Dehydrogenation of 1-Butene to 1,3-Butadiene without Steam

Oxidative dehydrogenation (ODH) reaction has emerged as a promising route for converting 1-butene to value-added 1,3-butadiene (BD). However, the low BD selectivity of the current catalysts (≤40%) and high steam input are now the challenge of this process. Here, we demonstrate the fabrication BiMo oxides immobilized on carbon nanotubes (BiMo/CNTs), employing the sol–gel method, as a novel catalyst for the ODH of 1-butene without steam in a fixed-bed reactor. The catalytic performances of BiMo/CNTs with different compositions in the absence of steam were investigated. When BiMo/CNTs at a molar ratio of 0.018 were employed in the ODH of 1-butene under reaction conditions of 440 °C, 1-butene/oxygen = 1/0.8, and no steam, the optimal BD yield was achieved as high as 52.2%. Under this reaction condition, the catalyst maintains good stability without steam after 10 h of reaction. This work not only promotes the application of carbon materials in oxidative dehydrogenation reaction, but also accelerates the production of 1,3-butadiene in a more economical way.