Biofilm-electrode process with high efficiency for degradation of 2,4-dichlorophenol

Abstract

2,4-Dichlorophenol (2,4-DCP) from chemical industry wastewaters has caused serious environmental pollution. Removal of 2,4-DCP using either physicochemical or biological methods is not very efficient. In this paper, a combination of biological and electrochemical methods gave satisfactory results. By comparisons of the degradation of 2,4-DCP and the removal of chemical oxygen demand (COD) in electrochemical, biological and biofilm-electrode processes, it was found that the biofilmelectrode process possesses the highest degradation efficiency and removal rate; both the pure electrochemical and the pure biological processes were far less efficient. The removal efficiency of 2,4-DCP using the biofilm-electrode process was 100% in 48 h, while that using the pure electrochemical and the pure biological processes were 62 and 42%, respectively. The experiments show that the current of 5 mA for the cathode of 9 cm 2 and the initial concentration 100 mg/l of 2,4-DCP were the optimal parameters of technology for the biofilm-electrode process. The excellent effects are due to the withdrawing electron action of bacterium, electrochemically anodic oxidation and cathodic dechlorination. It is the first time that the biofilm-electrode method was applied in 2,4-DCP degradation. Here, we demonstrated that biofilm-electrode process is a promising method to remove some aromatic compounds in industrial wastewater.

Anaerobic Treatment of Oily Wastewater Using A Biofilm-Electrode Reactor: A Kinetic Study And Energy Consumption

“…The removal efficiency of the investigated processes was 100%, 42%, and 61%, respectively. This improvement and increase in removal efficiency were due to the electrostimulation of bacteria (Zhang et al, 2011).…”

“…All these oxidants are produced in situ and used immediately; they can also be harmful to the biofilm in higher concentrations (García-García et al, 2015). Zhang et al, (2011) studied BER, in which microorganisms specifically attach to the electrode as a biofilm and play a pivotal role in biodegradation. They reported that applying over-optimum currents causes separation and fall-off microorganisms from the electrode (Zhang et al, 2011).…”

“…Zhang et al, (2011) studied BER, in which microorganisms specifically attach to the electrode as a biofilm and play a pivotal role in biodegradation. They reported that applying over-optimum currents causes separation and fall-off microorganisms from the electrode (Zhang et al, 2011).…”

“…This reduction in time also decreases the reactor volume, which leads to the lower design and implementation costs (Cardenas-Robles et al, 2013). Zhang et al (2011), in a study on the degradation of 2,4-dichlorophenol by BES in an anaerobic process, reported good results and high efficiency. They compared the removal efficiency of BES and biological (in the absence of electric current) and electrochemistry methods and showed that the bioelectrode process had higher efficiency than the other two methods, and the removal efficiency of pollutants was lower in pure biological and pure electrochemical processes.…”

Effects of Electrical Stimulation on the Degradation of Azo Dye in Three-Dimensional Biofilm Electrode Reactors

“…Electric current stimulation improved microbial metabolism and azo reductase activity. Concurrently, the surface of the GAC layer was charged by the current to become new GAC electrodes, which can produce anode reactions on the surface [23]. This greatly increased the specific area of the electrodes [24] so that the 3D-BERs still had good removal efficiencies at high X-3B influent concentrations.…”