Heterogeneously Porous Multiadsorbent Clay–Biochar
Surface to Support Redox-Sensitive Nanoparticles: Applications of
Novel Clay–Biochar–Nanoscale Zerovalent Iron Nanotrident
(C-BC-nZVI) in Continuous Water Filtration
An
eco-friendly layered-porous C-BC surface was prepared by intercalating
properties of layered bentonite clay (C) having high cation-exchange
capacity, with biochar (BC), containing pores and vast functionality,
and utilized to support redox-sensitive zerovalent iron (nZVI) nanotrident
particles. The synthesized C-BC-nZVI nanotrident was characterized
for morphology, porosity, crystallinity, functionality, and suspension
stability and then evaluated for various environmental applications
such as REE extraction, toxic metal removal, and sorption of dyes.
Results show heterogeneous pore distribution on the C-BC-nZVI surface
with dispersed-unoxidized 20–30 nm sized nZVI particles. C-BC-nZVI
had shown 100% extraction of REEs (La, Ce, and Nd) along with >90%
removal of various toxic metals (As, Cd, Cr, Ni, Hg, and Pb). In the
dye mixture, the nanotrident showed selective sorption of methylene
blue (MB). The impact of environmental complexities on the nanotrident’s
reactivity for metals and MB dye was further delineated using CrO42–, Ni2+, and MB. Results show
no influence of pH and dissolved organic matter (DOM) variation on
Ni2+ and MB sorption. Further efficient sorption, reduction,
and coprecipitation of all the contaminants, i.e., CrO42– (44.3 mg/g), Ni2+ (570.5 mg/g), and
MB (52.1 mg/g) in groundwater and <10 μg/L release in the
elute obtained from the continuous flow column until the breakthrough
point confirms the multifunctionality and applicability of the nanotrident
in the natural environment.