Centrifugal extractors utilize copper-plated iron melt-H2O2 to treat phenol-containing wastewater

Phenol-containing wastewater is a type of industrial wastewater with severe hazards. It originates mainly from the large amounts of wastewater discharged by industries such as wood distillation, pesticide production, resin manufacturing, plastics industry, dye production, foundries, paper mills, paint production, and synthetic ammonia plants, and it has a significant impact on water sources and aquatic organisms. Therefore, effective treatment measures must be taken for the generation of phenol-containing wastewater and for the existing phenol-containing industrial wastewater, in order to strictly control emissions.

To date, researchers have proposed many effective treatment methods for this issue, including activated carbon adsorption, biological methods, and chemical methods, but all of them have drawbacks such as short cycles, difficulty in regeneration, and high operating costs. Among them, the Fenton method is an advanced oxidation process for treating refractory organic pollutants, which utilizes a series of chain reactions involving Fe2+ and H2O2 to generate hydroxyl radicals. It has advantages such as simplicity, speed, and the ability to produce flocs; however, it suffers from issues including low utilization efficiency of the oxidant H2O2, poor oxidation efficiency, and relatively high treatment costs. To this end, the iron scrap corrosion cell method has been widely studied and applied in recent years. Also known as the internal electrolysis method, it involves using iron scraps and activated carbon to form a primary battery; chemical reactions of pollutants at the positive and negative electrodes, along with the electrochemical enrichment inherent to the primary battery, physical adsorption, and flocculation, are all utilized to achieve pollution removal.

This method consumes no energy, has low processing costs, and the iron scrap used mostly comes from industrial waste, making it practically useful for turning waste into value. Based on this, following the principle of galvanic cells, this study attempted to use copper-plated iron filings as a substitute for FeSO4 in the Fenton system to degrade phenol-containing simulated wastewater, and explored the impact of various related factors on the COD removal rate as well as their effectiveness in treating actual phenol-containing wastewater. First, the iron shavings are boiled in a hot sodium carbonate solution for 5 minutes to remove oil stains, then rinsed with water until the pH is nearly neutral. A small amount of dilute sulfuric acid is added to activate them for 3 minutes, after which they are rinsed again until the pH is nearly neutral. Then, copper sulfate solution was added to the pretreated iron filings; after stirring and reacting for 2 minutes, a thin layer of copper metal was deposited on the surface of the iron filings. These were washed, filtered under vacuum, and dried for later use.

The effect of the Tianyi Extraction CWL-M type centrifugal extractor in treating phenol wastewater using copper-plated iron solution and hydrogen peroxide (1) For treating phenol-containing wastewater with copper-plated iron solution and H2O2, the optimal operating conditions are: 30% H2O2 at a concentration of 12 mL/L, copper-plated iron solution at 5 mL/L, a pH value of 4–6, and a reaction time of 45 minutes at room temperature; the COD removal rate after the reaction can reach 96%. Moreover, when actual phenol-containing printing and dyeing wastewater was treated under these optimal conditions, its CODCr decreased from 5827 mg/L to 419 mg/L, and its color intensity dropped from 2000 to 30, meeting the **discharge standards. (2) Comparative experiments showed that the copper-plated iron solution not only provides the Fe2+ required for the reaction, but the copper coating also exerts a specific catalytic effect on the Fenton reaction, indicating that using such a solution as a catalyst is an effective method for treating phenol-containing wastewater.

Zhengzhou Tianyi Extraction http://www.cncuiqu.com

The phenol level in the wastewater is within the specified limits, but the wastewater contains copper ions. What is the allowable level of copper ions in wastewater discharge standards?