Kinetic Study of Nitrate Removal from Aqueous Solutions Using Copper-Coated Iron Nanoparticles

Abstract

Nitrates are considered hazard compounds for human health due to their tendency to be reduced to nitrites, in particular in reducing environment. Nano zero valent iron (nZVI) represents an efficient and low-cost adsorbent/reductive agent for nitrate removal from groundwater and wastewaters and a little addition of a second metal species (Cu, Pd, Ni, Ag) has proven to increase process effectiveness, by enhancing stability and oxidation resistance of nanoparticles. In this work Cu/Fe nanoparticles were loaded in a NO solution (100 mg L) and the removal efficiency was tested by monitoring nitrate concentration at selected time intervals. Results showed that the nitrate removal process involves both reduction and adsorption processes: the removal mechanism has been investigated, and the pseudo-first-order and pseudo-second-order-adsorption kinetic models were successfully tested.

Simultaneous stabilization of Pb and improvement of soil strength using nZVI

“…Clearly, these micro-bubbles are generated primarily from the oxidation of nZVI in the aqueous phase and are retained in the soil sample. In addition to that, the nitrogen and carbon dioxide, generated by the reduction of nitrate by nZVI and oxidation of natural organic matters in soil, respectively, may also contribute partially to the generation of micro-bubbles (Vilardi and Di Palma, 2017;. The increased the drying shrinkage occurred due to the reduced water content lead to the occurrence of massive fissures grown on the surface of nZVI-treated soil slurry.…”

Removal of nitrate from aqueous solution using nano zerovalent iron‐reduced graphene oxide composite: optimization of parameters

“…12 and Table 5, the experimental data were well fitted to the kinetic models with R 2 values above 0.90. This implies that the adsorption and catalytic reduction of nitrate by the composite follow the pseudo‐second‐order and pseudo‐first‐order models, respectively (Chen et al , 2013; Vilardi and Di Palma, 2017). The calculated k obs of 0.09 indicated that the nitrate reduction occurred at the interface of water and nZVI (Wang et al , 2013; 2014).…”

“…Nitrate removal by the nZVI-rGO composite includes simultaneous adsorption and chemical reduction reactions. As investigated previously, the adsorption process could follow the pseudo-second-order kinetic model, while the chemical reduction could be better described by the pseudo-firstorder kinetic model (Ho and McKay, 1999;Wang et al, 2014;Vilardi and Di Palma, 2017). The pseudo-first-order [Eq.…”

Metallic iron nanoparticles intensified production by spinning disk reactor: Optimization and fluid dynamics modelling

“…The analogy between plug-flow reactor (PFR) and SDR has been proposed by various authors: at high rotational velocity values (>1000 rpm), low viscosities (close to that of water) and high inlet flowrates, the bulk flow behaviour of SDR and PFR were proved to be very close [41,42]. The achievement of PFR flow conditions allows to high conversion rates and very good product quality (unimodal distribution size) to be obtained, reducing at the same time the residence time in the reactor maximizing the product yield [43]. In the production of metallic nanoparticles the reduction of residence time is fundamental, as well as reaching micromixing conditions [44].…”

“…Therefore, the achievement of micromixing conditions in the reactor vessel represents a fundamental goal to increase local supersaturation values and to favour crystal nucleation rather than crystal growth [45]. SDR technology has demonstrated its suitability for the production of well dispersed and unimodal nanoparticles [39,43,46,47] and for this reason it was selected for the optimization of nZVI production.…”