Absorbance spectral slopes for monitoring tropical peat water dissolved organic matter fractions during microbubble pre‐ozonation

Abstract

AbstractThe dissolved organic matter (DOM) protonated fractions of various hydrophobicities were correlated with the tropical peat waters' UV–Vis spectral slopes. This study was conducted to determine how microbubble pre‐ozonation affects UV–Vis spectral slopes in tropical peat water treatment processes This study was conducted to determine how microbubble pre‐ozonation affects UV–Vis spectral slopes in tropical peat water treatment processes. Microbubble pre‐ozonation was carried out at pH 7 followed by alum coagulation and activated carbon (AC) adsorption. The results showed that the log‐transformed UV–Vis absorption of processed peat water had four spectral slopes in the range of 220 to 420 nm. The degradation of the transphilic (TPH) DOM fraction had a strong negative correlation with the S220‐240 and S241‐272 values (R2 > 0.85). Similarly, the hydrophilic‐charged (HPIC) and hydrophilic‐neutral (HPIN) fractions had a strong negative correlation with the S220‐240 and S241‐272 values (R2 > 0.84 and R2 > 0.70). Meanwhile, the S273‐350 S>350 values had a low and negligible correlation with all analyzed DOM fractions (R2 < 0.30). The lower wavelength spectral slopes ratio (S220‐240/S241‐272) was moderately correlated with the DOM fraction, while the correlation with higher wavelength values was negligible. Based on these findings, the UV–Vis spectral slopes ratio at lower wavelengths appears to be useful information for developing a surrogate parameter of DOM fractions in peat water treatment processes.