TY - JOUR
AU1 - Cai, Y.
AU2 - Qiu, C.
AU3 - Yang, K.
AU4 - Tian, B.
AU5 - Bi, Y.
AB - Methylene blue is widely used in various industries. The discharge of industrial effluents with methylene blue residues may have hazardous effects on living systems. In this paper, the low-cost, eco-friendly, and abundant geoadsorbent natural manganese ore sand was used as an attractive material to remove methylene blue. The results indicated that the poorly crystalline manganese ore sand could simultaneously adsorb and degrade methylene blue. The pseudo-first-order and MnOII (I) kinetic models could describe the decolorization, but the latter had better predictive characteristics. The kinetics were affected by coexisting substances, but a decolorization efficiency of greater than 80% still could be achieved in actual water matrices. Characterization of manganese ore sand before and after use indicated that the degradation processes that occurred at pH values of 2, 3, 5, 7, and 10 included direct and indirect redox reactions. Specifically, the manganese ore sand behaved primarily as an oxidant at acidic pH, as a catalyst at alkaline pH, and simultaneously as oxidant and catalyst at a neutral pH. Possible degradation routes were proposed based on the suggested intermediates. The main behavior of the oxidant was demethylation of C–CH3 from methylene blue, and the degree of demethylation increased with decreased pH. As the catalyst, the C–N and C–S bonds on the central heterocycle could be further broken by manganese ore sand after demethylation. The performance of manganese ore sand is related to the content of high-valent Mn species.
TI - Adsorption–degradation of methylene blue by natural manganese ore: kinetics, characterization, and mechanism
JF - International Journal of Environmental Science and Technology
DO - 10.1007/s13762-023-05024-2
DA - 2024-01-01
UR - https://www.deepdyve.com/lp/springer-journals/adsorption-degradation-of-methylene-blue-by-natural-manganese-ore-MWVUSvLAfZ
SP - 1817
EP - 1830
VL - 21
IS - 2
DP - DeepDyve
ER -