Sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate

Endpoint summary

Description of key information

Adsorption / desorption

Adsorption study was conducted for evaluating the adsorption capacity of test chemical sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (CAS no. 57741-47-6) onto nanoclay at a temperature of 95°C (Yiqi Yang, et. al; 2005). In this study, Nanoclay Cloisites 10A, 15A, 30B and Na+were selected for dye sorption. Dye sorption onto nanoclay was performed at 95°C for 6 hours with a liquor-to-clay ratio of 100:1. A pre-study showed that dye sorption equilibrium was obtained within 6 hours. No purification was performed to either the commercial dyestuffs or the clays. Dye concentration differences in the bath before and after dyeing were used to obtain dye sorption data. A Hunterlab spectrophotometer was used to measure dye concentrations using the Beer–Lambert law.Before absorbance measurement, the clay was filtered from the dye liquor using syringe filters and a centrifuge to assure that small clay particles did not interfere with absorbance measurement. The clay treated with quaternary ammonium had a very strong sorption capability to acid red 266. This result indicated that the major contributive forces to dye sorption onto clay were van der Waals forces and hydrophobic interaction. Ionic attraction also played an important role. Nanoclay (10A, 15A, 30B and Na+) have a sorption capacity ranging from 150-700 mg dye per gram of the sorbent at a liquor-to-sorbent ratio of 100 to 1. Furthermore, it could have a sorption of 90% at an initial dye concentration of 6 g/L, or 60% based on the weight of the sorbent, indicating a very high dye affinity. This indicatesthat the substance sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (C. I. Acid Red 266) has a very strong sorption tosoil and therefore have negligible migration potential to ground water.

Additional information

Adsorption / desorption

Various experimental study and predicted data for the target compound sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (CAS No. 57741-47-6) were reviewed for the adsorption end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (Yiqi Yang, et. al; 2005) for the target chemicalsodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxy naphthalene-2-sulphonate(CAS No. 57741-47-6),adsorption experiment was conducted for evaluating the adsorption capacity of test chemical sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate onto nanoclay at a temperature of 95°C. In this study, Nanoclay Cloisites 10A, 15A, 30B and Na+ were selected for dye sorption. Dye sorption onto nanoclay was performed at 95°C for 6 hours with a liquor-to-clay ratio of 100:1. A pre-study showed that dye sorption equilibrium was obtained within 6 hours. No purification was performed to either the commercial dyestuffs or the clays. Dye concentration differences in the bath before and after dyeing were used to obtain dye sorption data. A Hunterlab spectrophotometer was used to measure dye concentrations using the Beer–Lambert law. Before absorbance measurement, the clay was filtered from the dye liquor using syringe filters and a centrifuge to assure that small clay particles did not interfere with absorbance measurement. The clay treated with quaternary ammonium had a very strong sorption capability to acid red 266. This result indicated that the major contributive forces to dye sorption onto clay were van der Waals forces and hydrophobic interaction. Ionic attraction also played an important role. Nanoclay (10A, 15A, 30B and Na+) have a sorption capacity ranging from 150-700 mg dye per gram of the sorbent at a liquor-to-sorbent ratio of 100 to 1. Furthermore, it could have a sorption of 90% at an initial dye concentration of 6 g/L, or 60% based on the weight of the sorbent, indicating a very high dye affinity. This indicates that the substance sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (C. I. Acid Red 266) has a very strong sorption to soil and therefore have negligible migration potential to ground water.

 

Another adsorption study was conducted for evaluating the adsorption capacity of test chemical sodium 6 -amino-5 -[[4 -chloro-2 -(trifluoromethyl)phenyl]azo]-4 -hydroxy naphthalene-2 -sulphonate (CAS no. 57741 -47-6) onto sewage sludge (NTRL report, Report no. OTS0514199, March 1988). Test chemical conc. used for the study was 0.5 mg/l (0.5 ppm).Three wastewater treatment were selected plants for sludge collection. These plants were coded A, B and C. All plants selected for study treated an influent containing at least 75% wastewater from textile dyeing and finishing processes. All three plants were activated sludge systems operated in extended aeration mode.Plant A is a municipal system typically processing 35 million gallons per day of wastewater. Approximately 90% of the wastewater is from industrial sources. The plant achieves 97-98% BOD reduction. Sludge obtained from this plant had been sand bed dried.Plant B is operated by atextilecompany and has a capacity of 2 million gallons per day. The influent is almost100%textile process wastewater.Plant C is a municipal plant processing 1.5 million gallons of wastewater per day with 75% of the influent from textile dyeing processes. Plant C achieves a 98% BOD removal with a 5 day residence time.For adsorption study, test solution was exposed in several experiments to sludge in a chromatography column. Sludge was obtained from the N.E. Clayton County sewage plant. This sludge contained about 0.9% dry solids. The sludge was allowed to settle, the supernatant decanted and the sludge washed with distilled H20. This was repeated to remove any water soluble chemicals from the sludge. The sludge was left in a closed container for thirty days to starve the bacteria. No bacterial count was made so it is possible that the sludge contained active bacteria.The sludge adsorption columns were prepared in 16 mm by 500 mm chromatography columns. The column was fitted with a stopcock at the lower end preceded by an inch of packed glass wool to prevent sludge from seeping out of the column, but allowing the dye solution to pass through. Approximately 500 ml of sludge solution was allowed tosettleand the top layer of H20 decanted. The column was then filled with sludge and the sludge was allowed to settle in the column. The stopcock was opened allowing excess water to drain off. This process was continued until the column was filled, leaving 1-inch at the top of the column for a glass wool plug. A Kelly infusion jar was attached to the column by a 2 inch piece of Teflon tubing. Dye solution was poured into the infusion jar and passed slowly through the sludge packed column. The effluent was collected and analyzed for dye content. Effluents were collected from the columns on a regular basis. Upon collection from the column the effluents were placed in clean freezer jars and maintained in a freezer until analyzed. Analysis was carried out using liquidchromatography and absorption spectrophotometry.Thus, it was possible by knowing the concentration of dyes and volume of the influent to the sludge column and the dye concentration and volume of the effluent to determine the actual quantity of each dye adsorbed on the sludge.The percentage recovery of the test chemical Acid Red 266 was determined to be 18.7%.These result certainly suggest that the test chemical Acid Red 266 is strongly adsorbed by waste treatment plant sludges and are very difficult to remove.This indicatesthat the substance sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (C. I. Acid Red 266) has a strong sorption to sewage sludge and therefore have negligible to slow migration potential to ground water.

 

From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical), the adsorption coefficient i.e KOC for test substance sodium 6 -amino-5 -[[4 -chloro-2 -(trifluoromethyl)phenyl]azo]-4 -hydroxynaphthalene-2 -sulphonate was estimated to be 3640 L/kg (log Koc = 3.561).The predicted KOC result based on the 5 OECD principles. This Koc value indicates that the substance sodium 6 -amino-5 -[[4 -chloro-2 -(trifluoromethyl)phenyl]azo]-4 -hydroxynaphthalene-2-sulphonate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

On the basis of above overall results for target chemical sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate (from peer reviewed journal, secondary source and modelling database Comptox Chemistry Dashboard), it can be concluded that the test substance sodium 6-amino-5-[[4-chloro-2-(trifluoromethyl)phenyl]azo]-4-hydroxynaphthalene-2-sulphonate has a strong to very strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.