Effect of preparation methods on morphology of active manganese dioxide and 2,4-dinitrophenol adsorption performance

Abstract

Herein active manganese dioxide was prepared by different methods using KMnO 4 and MnSO 4 ÁH 2 O as inorganic precursors. The impact of preparation methods on morphology and adsorption performance of the synthesized products was investigated. The experimental results show that the reaction temperature and pressure had a great effect on the morphology and adsorption performance of active manganese dioxide. The shape of active manganese dioxide prepared at room temperature and pressure was short rod-like while active manganese dioxide synthesized by hydrothermal method was mesoporous fibers and had better adsorption performance. The adsorption behavior of 2,4-dinitrophenol on mesoporous manganese dioxide was well described by Langmuir and Freundlich isotherm equation (R 2 >0.99) and pseudo-secondorder kinetic equation (R 2 >0.99), so the adsorption process maybe a chemical and monolayer adsorption. The pH of solution had significant effect on the adsorption performance of 2,4-dinitrophenol on mesoporous manganese dioxide. The adsorption capacity was 2.539 mg/g in the condition of pH ¼ 7.

Flexible Carbon-Fiber/Semimetal Bi Nanosheet Arrays as Separable and Recyclable Plasmonic Photocatalysts and Photoelectrocatalysts

“…During the photocatalytic process, SPR of semimetal Bi takes place under solar-simulated light irradiation, and charge separation and transfer can occur at the metal–carbon fiber interface under the excitation of the SPR. Due to the excellent electrical conductivity of carbon fibers, , they can trap the SPR hot electrons exerted from the SPR of semimetal Bi and create holes in semimetal Bi nanosheets. Both the electrons transferred to carbon fibers and the holes created in semimetal Bi can contribute to catalytic reactions.…”

“…As can be seen, the SPR of semimetal Bi takes place under solar-simulated light irradiation during the photoelectrocatalytic process. The carbon fiber with excellent electrical conductivity acting as a cocatalyst , can trap the SPR hot electrons exerted from the SPR of semimetal Bi, transfer electrons to the external circuit, and create holes in semimetal Bi nanosheets. The external voltage enhanced the separation of photogenerated electrons and holes.…”

Green Synthesis of Metal and Metal Oxide Nanoparticles for Recent Applications

“…These methods include wet chemical, solvothermal, precipitation, co-precipitation, controlled synthesis, sol-gel, hydrothermal, reflux, pyrolysis, sonochemical, low-temperature solution combustion, self-reacting, microemulsion, photochemical, and forced hydrolysis techniques [178,179]. Common synthesis approaches involve the oxidation of Mn(II) in a basic solution, oxidation by agents such as oxygen, potassium persulfate, and hydrogen peroxide, or the reduction of permanganate through various means [180,181]. Frequently used reducing agents include nitric acid (HNO3) [182], sodium hydroxide (NaOH) [183], hydrochloric acid (HCl) [184], and ammonium fluoride (NH4F) [185].…”

Separable and recyclable meso-carbon@TiO2/carbon fiber composites for visible-light photocatalysis and photoelectrocatalysis

“…Generally, the photocatalysis is a thermodynamically favorable reaction, which means surface molecular adsorption is the rate-determining step [77,78]. Compared with commercial P25 TiO 2 , meso-carbon@TiO 2 /carbon fiber composites exhibit a higher adsorbability [79,80]. During photocatalytic degradation of RMB, the amount of adsorbed RMB on meso-carbon@TiO 2 /carbon fiber composites is higher than that of commercial P25 TiO 2 .…”