Análise do transporte de carboximetilcelulose de sódio (cmc-na) e nanopartículas de ferro zero-valente (nzvi) estabilizadas em cmc-na em meio poroso

Abstract

An experimental study was conducted to evaluate sodium carboxymethyl cellulose (CMC-Na) and CMC-Na stabilized nano-scale zero-valent iron (nZVI) transport characteristics in porous media. Experiments were performed in a water-saturated sandbox with the following dimensions (0.55 m x 0.45 m x 0.0014 m). The transport tests were firstly conducted using LGB dye to characterize the media; then, CMC-Na was used to characterize the polymer transport through the media. The tests using CMC-Na were performed using two different concentrations: 0.2 % and 0.8 % (w/v). Furthermore, fresh nZVI was used to accomplish the transport using CMC-Na 0.8 % (w/v) as a stabilizer. The solutions were injected by two means: continuous lateral inlet injection and point injection, the last one simulating in situ injection methods. LGB transport showed heterogeneity in the sandbox packing, indicating layering effect. Through CMC-Na transport, it was possible to find that viscosity and specific gravity interfered in the solution flow; additionally, this phenomenon was reassured with nZVI transport. Moreover, it was possible to note the attaching and deposition in the media during the transport, leading to a mass recovery of 31.2 % of the total mass injected. It was also found that the mean residence time is affected by viscosity of the solutions. The hydrodynamic tests showed that Levenspiel’s dispersion models efficiently represent the acquired experimental data, showing for almost all experiments correlations superior to 0.8. However, the best presented model was big dispersion for its correlation was greater than 0.8 for all performed experiments