Solvent-free mechanochemically synthesized Zn layered hydroxide salts for the adsorption of naphtholate AS dye

• Published in: Applied surface science 2020-03, Vol.506, p.144930, Article 144930
• Main Authors: Santosa, Sri Juari, Sudiono, Sri, Wibawani, Rizqa Syah
• Format: Article
• Language: English
• Subjects: Adsorption; Dye; Grinding; Mechanochemical method; Solvent-free; Zn layered hydroxide salts
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2019.144930

[Display omitted] •A solvent-free mechanochemical method could be used to synthesize Zn LHSs.•Mechanochemically synthesized Zn LHSs were successfully prepared at OH/Zn molar ratio 0.6•Mechanochemically synthesized Zn LHSs showed similar characteristics as Zn LHSs prepared by coprecipitation method.•Adsorption of naphtholate AS on Zn LHSs closely followed the Langmuir isotherm model.•Mechanochemically synthesized Zn LHSs had relatively better capacity than Zn LHSs prepared by coprecipitation method for naphtholate AS dye. Solvent-free synthesis through a mechanochemical method is one of the most promising benign methodologies in the recent decades. In this study, a very simple solvent-free mechanochemical method for the synthesis of Zn layered hydroxide salts (Zn LHSs) by manual grinding in a mortar was reported in detail. With a single step grinding for fifteen minutes at ambient temperature, Zn LHSs were successfully synthesized from Zn(NO3)2·4H2O and NaOH with OH/Zn molar ratio 0.6. Based on the characterization results using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermal analysis (TGA/DTA) and scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS), the as-synthesized Zn LHSs (mechano-Zn LHSs) showed similar characteristics as Zn LHSs prepared by conventional coprecipitation method (copre-Zn LHSs) but with slightly worse crystallinity and lower dehydroxylation temperature. Mechano-Zn LHSs were highly pure with only insignificant noticeable contamination from other phases. Adsorption of naphtholate AS dye on mechano-Zn LHSs and copre-Zn LHSs was optimum at pH 9.14 and matched well in Langmuir isotherm model with capacity and energy of adsorptions were 0.67 × 10−3 mol/g and 23.79 kJ/mol for mechano-Zn LHSs which were slightly higher than those of copre-Zn LHSs, i.e. 0.62 × 10−3 mol/g and 23.18 kJ/mol, respectively.