کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4483472 1316889 2012 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Aggregation and deposition kinetics of carboxymethyl cellulose-modified zero-valent iron nanoparticles in porous media
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Aggregation and deposition kinetics of carboxymethyl cellulose-modified zero-valent iron nanoparticles in porous media
چکیده انگلیسی

Transport and deposition of carboxymethyl cellulose (CMC)-modified nanoparticles of zero-valent iron (NZVI) were investigated in laboratory-scale sand packed columns. Aggregation resulted in a change in the particle size distribution (PSD) with time, and the changes in average particle size were determined by nanoparticle tracking analysis (NTA). The change in PSD over time was influenced by the CMC-NZVI concentration in suspension. A particle–particle attachment efficiency was evaluated by fitting an aggregation model with NTA data and subsequently used to predict changes in PSD over time. Changes in particle sizes over time led to corresponding changes in single-collector contact efficiencies, resulting in altered particle deposition rates over time. A coupled aggregation-colloid transport model was used to demonstrate how changes in PSD can reduce the transport of CMC-NZVI in column experiments. The effects of particle concentrations in the range of 0.07 g L−1 to 0.725 g L−1 on the transport in porous media were evaluated by comparing the elution profiles of CMC-NZVI from packed sand columns. Changes in PSD over time could reasonably account for a gradual increase in effluent concentration between 1 and 5 pore volumes (PVs). Processes such as detachment of deposited particles also likely contributed to the gradual increase in effluent concentrations. The particle–collector attachment efficiency increased with CMC-NZVI particle concentration due to a rise in dissolved Na+ concentration with increased addition of Na-CMC. This inadvertent change in ionic strength led to decreased effluent concentrations at higher CMC-NZVI concentrations.

Figure optionsDownload high-quality image ( K)Download as PowerPoint slideHighlights
► CMC-coated zero-valent iron nanoparticles (CMC-NZVI) aggregate in aqueous solution.
► A coupled aggregation–deposition model was developed.
► Aggregation altered CMC-NZVI deposition rates over time during transport.
► Higher CMC-NZVI dose resulted in higher deposition and aggregation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Water Research - Volume 46, Issue 6, 15 April 2012, Pages 1735–1744
نویسندگان
, , ,