Adsorption Properties of Nano-MnO2–Biochar Composites for Copper in Aqueous Solution

Abstract

There is a continuing need to develop effective materials for the environmental remediation of copper-contaminated sites. Nano-MnO2–biochar composites (NMBCs) were successfully synthesized through the reduction of potassium permanganate by ethanol in a biochar suspension. The physicochemical properties and morphology of NMBCs were examined, and the Cu(II) adsorption properties of this material were determined using various adsorption isotherms and kinetic models. The adsorption capacity of NMBCs for Cu(II), which was enhanced by increasing the pH from 3 to 6, was much larger than that of biochar or nano-MnO2. The maximum adsorption capacity of NMBCs for Cu(II) was 142.02 mg/g, which was considerably greater than the maximum adsorption capacities of biochar (26.88 mg/g) and nano-MnO2 (93.91 mg/g). The sorption process for Cu(II) on NMBCs fitted very well to a pseudo-second-order model (R2 > 0.99). Moreover, this process was endothermic, spontaneous, and hardly influenced by ionic strength. The mechanism of Cu(II) adsorption on NMBCs mainly involves the formation of complexes between Cu(II) and O-containing groups (e.g., COO–Cu and Mn–O–Cu). Thus, NMBCs may serve as effective adsorbents for various environmental applications, such as wastewater treatment or the remediation of copper-contaminated soils.

Copper(II) adsorption by Opuntia ficus-indica biochar fiber–MnO2 composites

“…1. The diffraction peaks at 2θ = 25.4, 36.5, 41.5 and 65.9 from the biochar fiber-MnO 2 composites match the standard XRD pattern of the manganese oxide (JCPDS 80-1098), indicating the successful deposition of MnO 2 on the biochar surface [6,20]. The broad peak at 2θ = 24° is characteristic for graphite-type materials [9,13].…”

Facile synthesis of MnOx‐loaded biochar for the removal of doxycycline hydrochloride: effects of ambient conditions and co‐existing heavy metals

“…From Fig. (a), the absorption bands of all MnO x modified samples appeared at 838, 1042, 1620, 2919 and 3390 cm −1 were ascribed to the skeletal vibration of CH, CO, CC, CH 2 and OH bonds, respectively . The weaker peaks might be caused by introducing O‐containing functional groups .…”

“…Moreover, as metallic catalysts, MnO x can increase the selectivity and removal capacity of BC for contaminants . Several studies have demonstrated the effectiveness and wide applicability of composite adsorbents consisting of MnO x and BC for removal of heavy metals, such as lead (Pb 2+ ) , copper (Cu 2+ ) and cadmium (Cd 2+ ) . However, there are very few investigations on the absorption of organic pollutants by nano‐MnO 2 ‐BC composites.…”

Preparation of Material Based on Biochar - MnOx, Its Morphology, Thermal Stability and Phytotoxicity

“…(MnO 2 ) solid + M + + e → MnOOM M = Li + , Na + , K + Electrolytes used for applying MnO x nano-composites include water solutions (of salts (Na 2 SO 4 ) acids, alkalis), gel, organic or ion liquids (Varghese et al, 2015). In addition to its application as electrode materials, manganese oxide-based composite materials were applied on the C-carrier to absorb ions of arsenic, lead and copper (Zhou et al, 2017) from the water environment. Plans are being made for their application during catalytic decomposition of water into hydrogen and oxygen (Mette et al, 2012).…”