title: Study on the adsorption of Neutral Red from aqueous solution onto halloysite nanotubes.
abstract: Halloysite nanotubes (HNTs), a low-cost available clay mineral, were tested for the ability to remove cationic dye, Neutral Red (NR), from aqueous solution. Natural HNTs used as adsorbent in this work were initially characterized by XRD, FT-IR, TEM and BET. The effect of adsorbent dose, initial pH, temperature, initial concentration and contact time were investigated. Adsorption increased with increase in adsorbent dose, initial pH, temperature and initial concentration. The equilibrium data were well described by both the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 54.85, 59.24 and 65.45mg/g at 298, 308 and 318K, respectively. Batch kinetic experiments showed that the adsorption followed pseudo-second-order kinetic model with correlation coefficients greater than 0.999. Thermodynamic parameters of DeltaG(0), DeltaH(0) and DeltaS(0) indicated the adsorption process was spontaneous and endothermic. The results above confirmed that HNTs had the potential to be utilized as low-cost and relatively effective adsorbent for cationic dyes removal.
authors.affiliation: School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Luo
authors.forename: Yafei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.forename: Jindun
authors.initials: J
authors.lastname: Liu
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Junfang
authors.initials: J
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D009499:Neutral Red / Q000302:isolation & purification*; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D012996:Solutions; D009499:Neutral Red; D000077215:Clay