STUDY OF THE TECHNOLOGY FOR COLORED SOLUTIONS PURIFICATION THROUGH DISPERSION-ACTIVATED OXYGEN-HYDROGEN PROCESSES FOLLOWED BY ADSORPTION

Abstract

The article investigates the effect of preliminary mechanical treatment of a colored solution on the efficiency of adsorption purification from organic dyes, specifically methyl orange and brilliant green. Silica gel and activated carbon were used as adsorbents. The main aim of the study was to determine the effectiveness of different mixing modes prior to adsorption and their impact on subsequent decolorization. For mechanical treatment, milling and frame stirrers were used at rotation speeds of 30 and 60 rpm. A series of experiments was conducted to measure the color change of the solution over 80 minutes following treatment and subsequent purification. It was found that pre-mixing significantly increases adsorption efficiency compared to untreated samples: without treatment, the final color intensity was 45°, while after milling at 60 rpm, it decreased to only 15°, with no turbidity formation. The most effective approach was mixing with a milling stirrer before adsorption on silica gel: color intensity decreased to 10–15° after 80 minutes.Even at 30 rpm, it showed efficiency down to 20°. The frame stirrer showed worse results (35–38°) but provided better stability, which is important when working with activated carbon. Using a milling stirrer with carbon led to the formation of a fine suspension, complicating sampling and further analysis. Thus, optimal pre-treatment modes were identified: for silica gel – milling stirrer at 60 rpm; for activated carbon – frame stirrer at 60 rpm. It was established that applying adsorption post-treatment after preliminary mechanical activation allows a significant reduction in the residual dye concentration. The adsorption capacity of activated carbon after mechanical activation and oxidation increased by 1.3–1.6 times, depending on the dye type. The obtained results have high practical relevance for improving wastewater treatment technologies, particularly in industries using organic dyes – textile, leather, pulp and paper, and food industries.The proposed combination of methods is energy-efficient, requires minimal chemical reagents, reduces sludge formation, and can be integrated into existing treatment facilities. This ensures the economic feasibility of implementing the developed technology in both centralized and local industrial wastewater treatment systems.