Heterogeneous Fenton-Like Oxidation of Methylene Blue Using Alternative Catalysts

The usage of the low-cost catalysts for methylene blue removal from wastewater was investigated. Heterogeneous Fenton-like process consists of the use of a hydrogen peroxide solution, and an iron-rich catalyst, red mud and black nickel mud were used for that purpose. The factors such as the catalyst dose and the hydrogen peroxide solution volume were monitored. The results of experiments showed that the degradation of methylene blue dye in Fenton-like oxidation process using selected catalysts can be described by a pseudo-second-order kinetic model. The highest dye removal efficiency (87.15 %) was achieved using the black nickel mud catalyst after 30 minutes of reaction.

The Use of Red Mud and Black Nickel Mud in Sorption of 3,5-Dichlorophenol

This article discusses the use of alternative inexpensive adsorbents – wastes from the metal production - red mud (RM) and black nickel mud (BNM) and their sorption efficiency in 3,5-dichlorophenol removal. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and chlorine atoms. The effects of adsorbent dose, contact time, and temperature on sorption process were monitored. The results showed that the optimal conditions to achieve the highest sorption efficiency of 3,5-dichlorophenol were reached with the use of black nickel mud at the amount (2.0 g), sorption time (1 hour) and at increased temperature (45 °C). The sorption efficiency under these conditions was 87.99 %. With increasing sorption time, the sorption efficiency decreased and desorption occurred. The same behaviour was observed using red mud of the same amount (2.0 g) at the same temperature (45 °C); however, after 1 hour, sorption efficiency was slightly reduced (85.16 %) compared to black nickel mud. Anyway, both of used materials are suitable for the use as alternative sorbents of 3,5-dichlorophenol under suitable conditions.