Photocatalytic degradation of organic pollutants using TiO2-based photocatalysts: A review

Phenolic compounds are priority pollutants with high toxicity even at low concentrations. In this review, the efficiency of both conventional and advanced treatment methods is discussed. The applicability of these treatments with phenol and some common derivatives is compared. Conventional treatments such as distillation, absorption, extraction, chemical oxidation, and electrochemical oxidation show high efficiencies with various phenolic compounds, while advanced treatments such as Fenton processes, ozonation, wet air oxidation, and photochemical treatment use less chemicals compared to the conventional ones but have high energy costs. Compared to physico-chemical treatment, biological treatment is environmentally friendly and energy saving, but it cannot treat high concentration pollutants. Enzymatic treatment has proven to be the best way to treat various phenolic compounds under mild conditions with different enzymes such as peroxidases, laccases, and tyrosinases. This review covers papers from 2013 through January 2016.

/pdf/a-short-review-of-techniques-for-phenol-removal-from-2iihuqdwlr.pdf

A Short Review of Techniques for Phenol Removal from Wastewater

Benchmarking recent advances and innovative technology approaches of Fenton, photo-Fenton, electro-Fenton, and related processes: A review on the relevance of phenol as model molecule

Removal of phenolic compounds from industrial waste water based on membrane-based technologies

Global water pollution caused by dye and phenol contaminants has been reported to have reached an alarming level. These hazardous contaminants pose significant threats to humans and ecosystem, due to their toxicity, carcinogenicity, and mutagenicity. Various technologies have emerged for dyes and phenols removal from wastewater, such as physical adsorption, chemical oxidation, ozonation, extraction, and electrochemical treatments. However, these conventional methods are constrained by low efficiency and stability, high cost, and formation of harmful by-products. In recent years, there has been growing interest towards the development of immobilized enzyme technologies because they are more economical, effective and eco-friendly. Among various enzymes, peroxidases have generated extraordinary interest attributed to their ability to catalyze reactions of a variety of undesirable pollutants, such as dyes and phenol effluents. Immobilization of enzyme can enhance its catalytic efficiency, improve storage and operational stabilities, as well as allow enzyme recovery and reusability. Although numerous existing immobilized enzymatic systems have been established, their practical applications are limited due to mass transfer restriction, lack of feasibility for scaling-up and continuous operations, and difficulty for separation of immobilized enzymes from reaction mixtures. Therefore, much attention has been devoted to the immobilization of enzymes on nano-structured materials. In the current review, effects of process parameters on immobilized enzymes for applications in both dye and phenol treatment are discussed and summarized. Recent advanced technologies as well as challenges and future perspectives for research and development in this field are also highlighted.

An overview of immobilized enzyme technologies for dye and phenolic removal from wastewater

The potential of oxidoreductases, such as laccases and peroxidases, to remove organic pollutants from industrial wastewater and process water is addressed in this short review, with an emphasis on the peroxidase work completed or in progress in the authors’ laboratory. The major drawback to this treatment is the cost of the enzyme. However, with new sources and recent advances in the biotechnology industry, it is becoming a feasible alternative. A niche where enzymatic treatment may be first applied is not as a primary treatment but as a secondary treatment (pretreatment or polishing) coupled to existing physico-chemical or biological processes to increase their overall efficiency and economy. Soybean seed coat peroxidase is well suited because of its stability, ease of extraction, widespread availability and potential for adding to the soy value chain. Since crude enzyme often works better than purified enzyme, the only additional cost may be in concentrating the extract. This review briefly covers aspec...

Soybean peroxidase for industrial wastewater treatment: a mini review

Representative azo dyes (Acid Blue 113 [AB113] and Direct Black 38 [DB38]) were treated in a single step with soybean peroxidase (SBP) and hydrogen peroxide (H2O2), or in two steps, zero-valent iron (Fe°) pretreatment followed SBP/H2O2. The purpose of this research was to compare both treatment processes and to determine which one was the optimal for degradation of each azo dye. For AB113, the preferred process was the single-step process, 1.0 mM AB113 required 2.5 mM H2O2, 1.5 U/mL SBP at pH 4.0 for ≥ 95% color and dye removal and 30% total organic carbon (TOC) removal. For DB38, due to the products formed after Fe° reduction, which are enzyme substrates (aniline and benzidine; two of four products) a two-step process was preferred, which allowed reduction in the required SBP and H2O2 concentrations by 5- and 2-fold, respectively, compared to a single-step treatment for ≥ 95% color, dye, and aniline/benzidine removal and 88% TOC removal.

Soybean Peroxidase-Catalyzed Treatment of Azo Dyes with or without Fe° Pretreatment.

Background. Some industrial manufacturing processes generate and release dyes as water pollutants, many of which are toxic and hazardous materials. There is a need for milder, greener methods for d...

Laura G. Cordova Villegas

Papers

A Short Review of Techniques for Phenol Removal from Wastewater

Soybean peroxidase for industrial wastewater treatment: a mini review

Soybean Peroxidase-Catalyzed Treatment of Azo Dyes with or without Fe° Pretreatment.

Soybean Peroxidase Catalyzed Decoloration of Acid Azo Dyes.