Optimizing Humic Acid Removal by Modifying the Surface Chemistry of Plasma Polymerized Allylamine Coated Particles

Abstract

Plasma polymerized allylamine films were deposited onto quartz particles at low pressure to optimize humic acid removal by varying the plasma power, flow rate, and polymerization times. Increasing the plasma power increased the number of positively charged groups and humic acid removal. Increasing the allylamine flow rate increased the number of positively charged groups but maximum humic acid removal was observed at 6.48 sccm due to humic acid removal by positively charged and uncharged crosslinked species. Longer polymerization times increased the number of positively charged groups while similar humic acid removal resulted as the larger humic acid molecule cannot penetrate as readily into the film as the acid orange 7 used to determine the number of positively charged groups. Manipulation of the plasma parameters has shown to provide significant control over humic acid removal.

Exploiting Reactor Geometry to Manipulate the Properties of Plasma Polymerized Acrylic Acid Films

“…Plasma polymerization modifies surfaces via the deposition of a thin film containing specific functional groups. The organic monomer is introduced into the chamber as a vapor, fragmented via radio frequency discharge and deposited onto all surfaces in contact with the plasma [1]. The properties of plasma polymer films, such as chemistry, thickness and stability are conventionally controlled by varying the input monomer/gas, plasma power, monomer flow rate and deposition time.…”

Surface Modification of Sodium Montmorillonite Nanoclay by Plasma Polymerization and Its Effect on the Properties of Polystyrene Nanocomposites

“…It is a relatively simple, rapid, dry, and environment-friendly technique that is used to modify the surface of a great variety of materials. Even if this technique is normally used to modify the surface of different polymeric substrates, it has been used with success to modify different nanoparticles and other surfaces like zinc oxide, iron oxide, aluminum oxide, titanium oxide, carbon nanofibers (CNFs), CNTs, nanoclays [5,7,15,16,[31][32][33][34][35][36], and quartz [37,38]. Treatment with plasma can add a nanometric film that covers nanoparticles, modifying their surface properties.…”

“…If the plasma modification is carried out by using a monomer (plasma polymerization), this can generate a polymeric coating like the specific polymeric matrix over the nanoparticle with a desired increase in surface interaction, promoting an improvement in the adhesion between phases and the transference of properties between them [15,16]. For example, Jarvis and Majewski [37,38] have recently investigated changing the surface of quartz particles from hydrophobic to a hydrophilic character by using plasma treatment of allylamine. Longer polymerization times increased the number of positively charged groups and their hydrophilic behavior.…”