Simultaneous removal of tetracycline hydrochloride and As(III) using poorly-crystalline manganese dioxide

Hydrothermal synthesis of novel flower-like BiVO 4 /Bi 2 Ti 2 O 7 with superior photocatalytic activity toward tetracycline removal

“…The mobile phase was mixture of methanol-water (30:70, v/v, 2‰ formic acid containing in water) with a flow rate of 1 mL min -1 . The removal rate for tetracycline was calculated using the formula of (C 0 − C)/C 0 × 100%, where the C is the concentration of tetracycline at a given irradiated time and the C 0 means the initial concentration [19][20][21][22][23][24][25]. Meanwhile, the mineralization of tetracycline was monitored by determining the total organic carbon (TOC) by means of a TOC analyser (1030D, OI).…”

“…The mixture of methanol-water (30:70, v/v, 2‰ formic acid containing in water) was used as mobile phase with a flow rate of 1 mL min -1 . The injection volume was 20μl, the vaporizer temperatures were 300°C, the spectra was scanned in mass range from 50 to 600 m/z with the positive ion mode [19][20][21][22][23][24][25].…”

“…7a Table 1. Based on these results and previous studies [19][20][21][22][23][24][25], the proposed removal pathways were speculated in Fig. 8.…”

“…Meanwhile, a lot of extra peaks appeared along with the degradation of tetracycline (such as m/z = 461,434, 393, 375, 208, 171, 416, 402, 357, 191, 172). Combining with these detection results and the literature[19][20][21][22][23][24][25], the degradation removal process could be proposed as two main pathways. The first pathway showed that the intermediates (p1) with the m/z of 461 was caused from a cycloaddition of •OH locating the C11a-C12 double-bond, and the maximum adsorption band of tetracycline at the 357 nm would be disappeared by this effect.With continuous irradiation and attack of the active species (such as •OH, •O 2 − , and h + ), tetracycline molecules and the intermediates were broken down into secondary degradation products with lower molecular weight.…”

A microscopic and spectroscopic study of rapid antimonite sequestration by a poorly crystalline phyllomanganate: differences from passivated arsenite oxidation

“…[17][18][19] However, these materials can also readily oxidize many reduced toxic metals and metalloids, such as As(III), Cr(III), and Co(II), [20][21][22][23] as well as organic contaminants. 24,25 Many Mn oxides found in surface environments are poorly crystalline, of biogenic origin and highly reactive. Specically, d-MnO 2 , an amorphous crystalline form of hexagonal birnessite, is quite reactive with respect to As(III) oxidation.…”