The removal of Pb2+ ion by MnFe2O4/waste tea leaves biochar and mechanism of adsorption

Autor: Thitipone Suwunwong, Patsara Danwittayakul, Chuleeporn Thanomsilp, Piyanuch Siriwat, Suchada Chantrapromma, Khamphe Phoungthong
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Materials Research Express, Vol 8, Iss 1, p 015505 (2021)
Druh dokumentu: article
ISSN: 2053-1591
DOI: 10.1088/2053-1591/abd4b2
Popis: In order to transform waste tea leaves into a useful/valuable material for removal of Pb ^2+ ions from wastewater, MnFe _2 O _4 /biochar was synthesized. The tea waste was pyrolyzed at 500 °C to obtain the biochar. Effects of the composition of tea leaves on the physicochemical properties of biochar were evaluated. Biochar and MnFe _2 O _4 /biochar were mainly organic matter. Regarding inorganic components, aside from Fe and Mn there were considerable albeit small amounts of the mineral elements K and Ca in the MnFe _2 O _4 /biochar. The MnFe _2 O _4 /biochar is porous with a specific surface area of 24.38 m ^2 g ^−1 , and the surface is loaded with MnFe _2 O _4 and amorphous MnO _2 particles. Also carboxylic acid, hydroxyl, and carbonyl functional groups were formed on the MnFe _2 O _4 /biochar surfaces. The surface area and pore volume characteristics of the MnFe _2 O _4 /biochar were also increased compared with the baseline biochar, and the prepared MnFe _2 O _4 /biochar had mesostructure. The modification of biochar into MnFe _2 O _4 /biochar improved adsorption of Pb ^2+ ions with the removal increased to ∼98%. The Freundlich isotherm and the pseudo-second order kinetic models matched well Pb ^2+ adsorption onto the MnFe _2 O _4 /biochar.
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