Adsorption of solophenyl dyes from aqueous solution by modified nanozeolite from bottom ash and its toxicity to C. dubia

Abstract

Background: It is known that wastewater from textile industries are responsible for producing large amounts of highly contaminated effluents by various types of synthetic dyes. These compounds can be toxic, and in some cases, are carcinogenic and mutagenic and its removal is recommended.

Application: In the area of water purification, nanomaterials have been applied for removal of several compounds. Of the four classes of nanomaterials, zeolites have demonstrated good results for the removal of dyes. Nanozeolite synthesized from bottom ash and modified with hexadecyltrimethylamonium (ZMB) was used as adsorbent to removal of Solophenyl Navy (SN), Solophenyl Turquoise (ST) and their hydrolyzed forms (SNH and STH, respectively) from simulated textile wastewater.

Method: The physical-chemical characterization of materials was presented by using relevant analytical methods (XRD, SEM, BET surface area, etc.). Effects of parameters such as initial dye concentration, contact time and equilibrium adsorption were evaluated. The adsorption kinetics followed the pseudo-second-order model.

Results: Langmuir isotherm model shows the best fit for most dyes-ZMB systems. In order to identify if ZMB presented toxicity for the environment, bioassay and toxicity identification evaluation (TIE) with C. dubia were performed. The leached of ZMB was toxic to daphinids (11.3 TU).

Conclusion: TIE results appointed that the main cause of the toxicity could be due the surfactant and metal ions presents in aqueous solution.