Hydrophobic-modified metal-hydroxide nanoflocculants enable one-step removal of multi-contaminants for drinking water production

Abstract

Summary Flocculation is a mainstream technology for the provision of safe drinking water but is limited due to the ineffectiveness of conventional flocculants in removing trace low-molecular-weight emerging contaminants. We described a synthesis strategy for the development of high-performance nanoflocculants (hydrophobic-organic-chain-modified metal hydroxides [HOC-M]), imitating surfactant-assembling nano-micelles, by integration of long hydrophobic chains with traditional inorganic metal (Fe/Al/Ti)-based flocculants. The core-shell nanostructure was highly stable in acidic stock solution and transformed to meso-scale coagulation nuclei in real surface water. In both jar and continuous-flow tests, HOC-M was superior over conventional flocculants in removing many contaminants (turbidity, UV 254 , and DOC: >95%; TP and NO 3 -N: >90%; trace pharmaceuticals [initial concentration: 100 ng/L]: >80%), producing flocs with better structural and dewatering properties, and lowering the environmental risk of metal leaching. The rationally designed nanoflocculants have large application potential, as a solution to increasing public concern about micro-pollutants and increasing water quality requirements.

Sequestration of Phenols from Water into Poly(α-olefins) Facilitated by Hydrogen Bonding Polyisobutylene Additives

“…We also briefly examined some substituted imidazoles to see how substitution on the imidazole would affect the efficiency of sequestration of phenolics from water. We prepared a polyisobutyl-2-phenyl imidazole (11) and the polyisobutylbound tetrasubstituted-imidazole (12). This latter imidazole 12 is a version of a prior imidazole whose imidazolium salts are reported to have remarkable alkaline stability.…”

“…Phenolics are often byproducts of other industrial processes. − Whatever the source, these phenolics are generally highly toxic water pollutants, and a variety of procedures have been used to affect their removal from water. Common processes for removal of trace phenolics from water include oxidative degradation, biological treatments, flocculation, , liquid/liquid extraction, ,, or, most commonly, adsorption by solid supports. ,− In some cases, these procedures can be combined.…”

Development and Application of a Hydrogeochemical Model for the Groundwater Treatment Process in Waterworks

“…The flocculant is used to overcome the electrostatic repulsive forces and allow the interfering materials to agglomerate. In addition, a flocculation agent is added to weigh the flakes, because the metal hydroxide sludge formed during flocculation does not sediment well due to its high water content [27]. H 2 O 2 as an oxidizing agent, polyaluminum chloride (PAC) as a flocculant, and polyacrylamide as a flocculant are added to the water through the metering devices.…”

Influence of DOM characteristics on the flocculation removal of trace pharmaceuticals in surface water by the successive dosing of alum and moderately hydrophobic chitosan

“…metal salts) and flocculants (e.g. chitosan) using hydrophobic organic segments, which has shown promising results in several cases (Du et al, 2018;Liu et al, 2019;Ng et al, 2019;Ren et al, 2017;Yang et al, 2020b;Yang et al, 2021;Zheng and Taylor, 2020).…”

“…It has been shown that introducing a moderate amount of hydrophobic segments strengthens pair-wise binding interactions among flocculants, TrOCs and coexisting particles/colloids, which promotes contaminant aggregation (floc formation) and notably improves the removal of trace pharmaceutical (TrPs) (Liu et al, 2019;Ren et al, 2017;Yang et al, 2020b;Yang et al, 2021).…”