Respirometric Study of Optical Brighteners in Textile Wastewater

Abstract

Optical brighteners (OBs) are colorless fluorescent dyes, widely used in industry to improve whiteness in materials. Nearly 80% of all OBs in the market are derivatives of stilbene. They absorb the near-ultraviolet light and re-emit most of it in the blue range as visible fluorescence. OBs are commonly applied on textiles, detergents, paper and plastic products, among others. OBs have a low degradation ratio. In biological plants, they can only be partially removed by adsorption into the sludge and a tertiary treatment could be required to fully remove them. Part of them may persist and can be found in river and lake waters. The current work aims to evaluate the effect of the OBs in the bacterial activity of biological wastewater treatment plants. The influence of two commercial OBs (Goldblanc BHA and Leucophor PC) on respiration rate was monitored by means of a semi-continuous electrolytic respirometer, in order to obtain information related to the growth of the biomass and the degradation of the substrate. Their acute toxicity was also determined. It was concluded that the OB effect on bacteria population is variable depending on its chemical structure. Unlike the former, the Leucophor-PC brightener had an impact on the respirometric rate.

Identification of Fluorescent Brighteners as Another Emerging Class of Abundant, Ubiquitous Pollutants in the Indoor Environment

“…Thus, they are expected to exhibit high persistence (P), bioaccumulation (B), and toxicity (T). In fact, there is evidence that some FBs have multiple toxicities, such as developmental toxicity in aquatic organisms, − and can be harmful to humans owing to their association with cancer, genetic mutations, and eczema. , FBs have been reported to be persistent in the environment and resistant to biodegradation owing to their chemical stability; consequently, they are likely to accumulate on regional and global scales. However, although a broad range of FBs have been recorded with worldwide applications in large qualities for decades, the available literature on their environmental occurrence, distribution, and toxicity remains extremely limited.…”

The Influence of Iron Ions on Optical Brighteners and Their Application to Cotton Fabrics

“…The role of OBs in detergent formulation for washing cotton fabrics is to improve the optical and UV properties. Previous research has mainly focused on the optical properties of OBs in detergents but not on the UV Materials 2021, 14, 4995 2 of 14 properties [3,[19][20][21]. OBs in detergents can provide UV protection properties as an added value of textiles in the washing process [18,[22][23][24][25][26].…”

Isolation, Identification, and Selection of Bacteria With Proof-of-Concept for Bioaugmentation of Whitewater From Wood-Free Paper Mills

“…Carbohydrates increase the biological oxygen demand, leading to the growth of mucus, while sizing and binding agents cause the formation of stickies, which impair the properties of the paper ( Miranda et al, 2008 ; Licursi et al, 2016 ). Residues of azo dyes are unwanted visual contaminants and fluorescent stilbene dyes are recalcitrant and toxic to aquatic life ( Salas et al, 2019 ). To the best of our knowledge, no specific treatment studies to address these issues associated with wood-free paper production have been conducted.…”