Transport and retention behavior of carbonaceous colloids in natural aqueous medium: Impact of water chemistry

• Published in: Chemosphere (Oxford) 2019-02, Vol.217, p.213-222
• Main Authors: Jahan, Shanaz, Alias, Yatimah Binti, Bakar, Ahmad Farid Bin Abu, Yusoff, Ismail Bin
• Format: Article
• Language: English
• Subjects: Agglomeration; Carbon - chemistry; Carbon nanoparticles; Chromatography - methods; Colloids - chemistry; Graphene oxide quantum dots; Graphite - chemistry; Nanoparticles; Natural organic matter; Organic Chemicals - analysis; Osmolar Concentration; Quantum Dots; Retention profile; Sodium Chloride - analysis; Transport; Water - chemistry
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2018.11.015

Carbon based materials are emerging as a sustainable alternative to their metal-oxide counterparts. However, their transport behavior under natural aqueous environment is poorly understood. This study investigated the transport and retention profiles of carbon nanoparticles (CNPs) and graphene oxide quantum dots (GOQDs) through column experiments in saturated porous media. CNPs and GOQDs (30 mg/L) were dispersed in natural river water (RW) and passed through the column at a flow rate of 1 mL/min, which mimicking the natural water flow rate. After every 10 min, the column effluents were collected and the mass recovery and retention profiles were monitored. Results indicated that the transport of both carbonaceous colloids was predominantly controlled by surface potential and ionic composition of natural water. The CNPs with its high surface potential (−40 mV) exhibited more column transport and was less susceptible to solution pH (5.6–6.8) variation as compared to GOQDs (−24 mV). The results showed that, monovalent salt (NaCl) was one of the dominating factors for the retention and transport of carbonaceous colloids compared to divalent salt (CaCl2). Furthermore, the presence of natural organic matter (NOM) increased the transport of both carbonaceous colloids and thereby decreases the tendency for column retention. [Display omitted] •Transport of CNPs and GOQDs under natural water was explored.•Transport capacity was decreased with increasing ionic strength of solution.•GOQDs showed less transport compared to CNPs due to less surface potential.•Presence of NOM enhanced the transport of CNPs and GOQDs.•One-site kinetic deposition model described well the experimental BTCs.