# Recent Developments and Emerging Trends in Paint Industry Wastewater Treatment Methods
## 3 Paint Industry Wastewater Treatment Methods
### Treatment by Advanced Oxidation Processes  
Advanced oxidation processes (AOPs) can efficiently decompose degradation-resistant organic waste and remove it from wastewater [71]. Some of these processes are, for example, [PERSON]'s oxidation, photo-Fenton, ozonation, or photo-catalytic degradation [72]. These techniques have been found to be very effective tools for the treatment of toxic organic pollutants in dye- and heavy metal-containing effluents. Of the mentioned AOPs techniques, [PERSON]'s oxidation and photo-Fenton processes have been studied for the treatment of paint industry effluents (Table 4) [73]. During the [PERSON]'s oxidation process, a solution of H2O2 and ferrous ions is applied for the oxidization of the contaminants in the wastewater. The process can be affected by the dose of H2O2, the pH, and the catalyst concentration. The treatment of water-based \begin{table}
\begin{tabular}{p{71.1 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Treatment Method** & **Treatment Parameters** & **Results** & **Source of Wastewater** & **References** \\ \hline [PERSON]’s oxidation process using rust particles & 10 g rust particles/L within 70 h & COD removal 80\% rust materials practically not an efficient source of Fe ions & Grab from painting unit of Profilo Telra plant, manufacturing televisions & [74] \\ \hline Fenton and photo-Fenton processes & All processes were carried out in pH 3.0 15.15 \(\times\) 10\({}^{-3}\) mol/L FeSO4 during 6 h & Photo-Fenton process assisted with solar radiation, reductions of 99.5 and 99.1\% of COD and TOC levels photo-Fenton’s is very efficient in treating alkyl resin using solar light compared to artificial source & & \\ \hline \hline \end{tabular}
\begin{tabular}{p{71.1 pt} p{113.8 pt} p{113.8 pt}} \hline \hline \multicolumn{2}{p{71.1 pt}}{} & Sample volume 250 mL, sample temperature 24 \({}^{\circ}\)C, pH = 3 stirring for 5 min at 200 rpm and subsequently process & 81\% of COD removal sludge generated in the Fenton’s process was not as much as in coagulation, hazardous chemical sludge clearance necessary & Treatment and recycling facilities of highly polluted water-based & [76] \\ \hline \hline \multicolumn{2}{p{71.1 pt}}{} & Ternary photocatalyst containing iron nitride, carbon nitride, and hematite (Fe3N/Fe2O3/C3N4) catalyst dosage 5 ppm rhodamine B concentration, pH 3.5 & Removal of rhodamine B solutions and CO2 photoduction 98\% of the contaminant was removed over the photocatalyst in the aqueous phase & & [77] \\ \hline \hline \multicolumn{2}{p{71.1 pt}}{} & Abbreviations: BOD—biochemical oxygen demand, COD—chemical oxygen demand. & & \\ \end{tabular}
\end{table} 
Table 4: AOPs treatment methods for paint industry wastewater. -paint wastewater using [PERSON]'s oxidation process has been tested using different [PERSON]'s catalysts and photo-Fenton's oxidation [74; 75; 76]. Different catalysts for [PERSON]'s oxidation process were studied for enhancing the COD removal efficiency by estimating the effects of column dimension, size of packing material, the dosage of reactive, pH, and reaction time based on packed columns and mixed reactors [74]. Oxidized iron rust particles were used as the catalyst for the [PERSON]'s process, enhancing the removal efficiency of COD to around 80%. Despite enhanced COD removal efficiency, using oxidized iron materials as catalysts is an impractical and inefficient source of Fe ions because low pH can cause the generation of dissolved metal ions, and the small particles of Fe can harm the rate of filtration [74]. The correlation has been studied between the effectiveness of Fenton's and photo-Fenton's oxidation and the application of sunlight and artificial radiation for the removal of COD, total organic carbon, and phenolic compounds from alkyld resin manufacturing wastewater.