Three dimensional BC/rGA aerogel: preparation, characterization, and adsorption of Cr(VI)

Abstract

Graphene-based composite aerogel doped with other low-cost materials can reduce the cost and promote the use in water treatment. This work prepared ball-milled biochar/reduced graphene oxide aerogel (BC/rGA) using GO and low-cost ball-milled biochar (BC) in a certain proportion with the freeze-thawing technique and sol–gel method, and applied BC/rGA on the Cr(VI) removal from aquatic environments. The characterization results showed that aerogel had a honeycomb briquette three-dimension (3D) and mesoporous structure with interconnected pores, and proved the preparation progress of aerogel in principle. Compared with GO, rGA and BC/rGA had better adsorption performance with 3D structure and well-developed pores, and BC/rGA with the mixture ratio of BC and GO of 1:4 was more appropriate. The adsorption kinetics data of rGA and BC/rGA(1:4) were fitting well with the pseudo-second-order model (R2 > 0.951), and the isotherm adsorption results were fitting the Langmuir model well (R2 > 0.974). The results demonstrated that the adsorption process was monolayer and endothermic adsorption involving chemisorption. Additionally, the adsorption capacities of rGA and BC/rGA(1:4) at solution pH 2 were 3.71 and 3.89 times greater than those at solution pH 8, respectively. High background ion strength and low temperature slightly inhibited the adsorption of Cr(VI) by both rGA and BC/rGA(1:4). The adsorption mechanisms of Cr(VI) on rGA and BC/rGA(1:4) were electrostatic interaction, reduction and ion exchange. The use of BC/rGA could reduce the cost and promote the green reuse of agricultural waste. Overall, BC/rGA could be used as a promising green adsorbent alternative for the feasible treatment of heavy metal contaminated water. Graphical Abstract

A photothermal MoS2 decorated biomass carbon-based aerogel with a directionally aligned porous structure for mitigating heavy metal stress under seawater acidification

“…In contrast, aerogels possess a controlled pore structure and high surface area, which offers sufficient adsorption sites for metal ions. 24 In addition, aerogels are easy to separate and recycle, which has the potential for practical applications in the complex marine environment.…”

Treatment of Cadmium-Contaminated Water Systems Using Modified Phosphate Rock Powder: Contaminant Uptake, Adsorption Ability, and Mechanisms

“…The adsorption method is simple, efficient, economically feasible, environmentally friendly, and safe [15]. As such, it is often applied to remove heavy metals in polluted aqueous environments [3,16].…”

Adsorption Studies of Pb(II) and Cd(II) Heavy Metal Ions from Aqueous Solutions Using a Magnetic Biochar Composite Material

“…These iron-based nano-composite materials also offer a high surface area for better adsorption of pollutants. Magnetic biochar composite (MBC) materials have been studied in the past for the removal of heavy metals like lead, chromium, arsenic, cadmium, etc., from water and soil [16][17][18][19][20]. In spite of many useful available research outcomes, the formulation of magnetic biochar composite and its functionalization and adsorption mechanism must be studied and discussed further for better understanding.…”