Facile synthesis of graphene wool doped with oleylamine-capped silver nanoparticles (GW-αAgNPs) for water treatment applications

Abstract

The facile synthesis of graphene wool doped with oleylamine-capped silver nanoparticles (GW-αAgNP) was achieved in this study. The effect of concentration, pH, temperature and natural organic matter (NOM) on the adsorption of a human carcinogen (benzo(a)pyrene, BaP) was evaluated using the doped graphene wool adsorbent. Furthermore, the antibacterial potential of GW-αAgNP against selected drug-resistant Gram-negative and Gram-positive bacteria strains was evaluated. Isotherm data revealed that adsorption of BaP by GW-αAgNP was best described by a multilayer adsorption mechanism predicted by Freundlich model with least ERRSQ < 0.79. The doping of graphene wool with hydrophobic AgNPs coated with functional moieties significantly increased the maximum adsorption capacity of GW-αAgNP over GW based on the qmax and qm predicted by Langmuir and Sips models. π-π interactions contributed to sorbent-sorbate interaction, due to the presence of delocalized electrons. GW-αAgNP-BaP interaction is a spontaneous exothermic process (negative $$\Delta H^\circ$$ Δ H ∘ and $$\Delta G)$$ Δ G ) , with better removal efficiency in the absence of natural organic matter (NOM). While GW is more feasible with higher maximum adsorption capacity (qm) at elevated temperatures, GW-αAgNP adsorption capacity and efficiency is best at ambient temperature, in the absence of natural organic matter (NOM), and preferable in terms of energy demands and process economics. GW-αAgNP significantly inhibited the growth of Gram-negative Pseudomonas aeruginosa and Gram-positive Bacillus subtilis strains, at 1000 mg/L dosage in preliminary tests, which provides the rationale for future evaluation of this hybrid material as a smart solution to chemical and microbiological water pollution.

Hexadecylamine functionalised graphene quantum dots as suitable nano-adsorbents for phenanthrene removal from aqueous solution

“…The sum of squared errors (SSE) (eqn (5)) was utilised to validate all adsorption models. 48,49 q e = K d C e q e = K F C N e where K F (mg g −1 ) (L mg −1 ) N and N are the Freundlich constant and intensity parameter, which describe multilayer sorption capacity and heterogeneity indices; q max (mg g −1 ) and K L (L mg −1 ) are the Langmuir monolayer sorption capacity and constant associated with solute–surface interaction energy, respectively; K s (L mg −1 ) and q max (mg g −1 ) are Sips isotherm model constants, and maximum sorption capacity are Sips isotherm model constants and maximum sorption capacity, and m s is Sips isotherm exponent; q e is the amount of solute adsorbed (mg g −1 ), C e is the equilibrium non-adsorbed concentration (mg L −1 ), and K d (L g −1 ) is the sorption distribution coefficient. 50…”

“…However, the Sips model could reduce to the Langmuir or Freundlich model subject to changes in concentration of pollutants and surface interactions with the adsorbents. 30,49…”

“…However, the Sips model could reduce to the Langmuir or Freundlich model subject to changes in concentration of pollutants and surface interactions with the adsorbents. 30,49 Overall, the Sips maximum sorption capacity (q m ) and adsorption capacities (K d & K F ) revealed that the introduction of doping agent (N) and co-dopants (SN) enhanced the adsorption performance of the GQDs. This can be attributed to potentially improved surface hydrophobicity due to chemical modications, as well as smaller particle size and enhanced surface morphology and crystal structure as described in the previous sections.…”

Advanced Polymeric Nanocomposites for Water Treatment Applications: A Holistic Perspective

“…The toxicity of the adsorbent, when used for water filtration, is a major concern. Cellulose and other carbonaceous adsorbents (i.e., graphene, carbon nanotubes) have received significant attention for water purification due to their large surface area and affinity for inorganic and organic pollutants, as well as microbial contaminants [129,130]. Their toxicity, on the other hand, is relatively unknown and this requires more evaluation.…”