Application of Zn-AL-NO3- layered double hydroxide as Nano-sorbent for Removal of Direct red 81dye (DR81) from Textile wastewater

In the present project the zinc–aluminum layered double hydroxide (Zn-Al LDH) was synthesized by a simple co-precipitation method with controlled pH at 9±0.2 and followed by thermal treatment (45°C) [1]. The Synthesized zinc–aluminum layered double hydroxide was successfully applied as a solid-phase extraction nano-sorbent for the separation and pre-concentration of trace levels of DR81 (direct red 81) from Textile wastewater samples [2]. The effect of several parameters such as type of interlayer anion in Zn-Al LDH structure, pH, sample flow rate, elution conditions, amount of nano-sorbent, sample volume and co-existing ions on the extraction efficiency of the analytes were investigated. The results showed that DR81 could be retained on the Zn-Al (NO3–) LDH at pH 8. The retained DR81 could be stripped from the Zn-Al (NO3–) LDH by 2.5 mL of 2.0 mol L−1 NaOH. The optimized method was successfully applied to the extraction of DR81 from various Textile wastewater samples [2].