Adsorption removal of Cu2+ and Ni2+ from waste water using nano‐cellulose hybrids containing reactive polyhedral oligomeric silsesquioxanes

Cellulose is an important biomass in natural material fields. Reactive polyhedral oligomeric silsesquioxane (R‐POSS) bearing multi‐N‐methylol groups is novel high reactive POSS monomer. The nano‐cellulose hybrids containing R‐POSS were synthesized by crosslinking reaction. It was interesting to investigate properties and applications of hybrids containing R‐POSS. In this work, nano‐cellulose hybrids as novel biosorbent were used for adsorpting copper and nickel ions in aqueous solution. Adsorption kinetics and equilibrium isotherm of Cu²⁺ and Ni²⁺ on the nano‐cellulose hybrids were investigated. The results showed that R‐POSS had been grafted to cellulose macromolecule. The nano‐cellulose hybrids could form new adsorptive position for heavy metal ions. The adsorption capacities of hybrid materials were obviously higher than that of control cellulose. The adsorption of heavy metal ions on nano‐cellulose hybrids followed the second‐order model. The equilibrium isotherms for adsorpting copper and nickel ions on the hybrids followed Langmuir isotherm model. Nano‐cellulose materials containing POSS as biosorbents or ultrafiltration membranes would be used in separation of toxic heavy metal ions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Preparation of nano‐structured pig bone hydroxyapatite for high‐efficiency adsorption of Pb2+ from aqueous solution

The nano‐structured hydroxyapatite was prepared from pig bone materials by mineralization. The obtained nano‐structured bone was much better compared to the bone without nanostructure for removing Pb²⁺. The process was investigated under different conditions including contact time, initial Pb²⁺ concentration, and pH. The pseudo‐second‐order kinetic model and Langmuir isotherm model were suitable for describing adsorption process. Moreover, the maximum adsorption capacities of nano‐structured bone and bone without nanostructure were 312.5 and 96.1 mg/g, respectively. Overall, the advantages of excellent adsorption capacity and simple mineralization together with low cost make nano‐structured bone an attractive material for removal of Pb²⁺ from aqueous solution.     

A dynamic buildup growth model for magnetic particle accumulation on single wires in high‐gradient magnetic separation

Magnetic fluids containing nano or submicron magnetic particles and their applications to food, biological, and pharmaceutical systems have recently attracted considerable attention. Magnetic particles can be collected efficiently in magnetizable matrices (e.g., iron wires) in high‐gradient magnetic separation processes. However, capture efficiencies based on results for clean, particle‐free, wires may be seriously in error because the particle accumulation on the wire distorts the flow and the magnetic fields, and thus influences the capture efficiency. A model is developed here in which the dynamic growth process is treated as a moving boundary problem, with the growing front tracked explicitly by marker points distributed evenly over its surface. The flow field and magnetic field are calculated using a finite element method, and a particle trajectory model is used to calculate the deposition flux on the surface. The marker point distribution and the buildup shape are updated at each simulation step. Simulation results show that, for weakly magnetic particles, the accumulation exhibits a smoothly growing front, whereas for strongly magnetic particles, an instability occurs, leading to dendritic growth. The capture efficiency decreases dramatically as particle accumulation increases; and this trend is more prominent for the transverse configuration than it is for the longitudinal configuration. The simulation results show good agreement with experimental results from the literature. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Separation and recovery of cellulose and lignin using ionic liquids: a process for recovery from paper‐based waste

BACKGROUND: The production of paper makes use of cellulose and lignin as a raw material, and almost all cellulose and lignin production comes from raw wood materials, contributing to deforestation and resulting in potential environmental harm. It is therefore beneficial to develop technologies for cellulose and lignin recovery for re‐use and sustainability of resources. RESULTS: Three imidazolium based ionic liquids (ILs), 1‐(2‐cyanoethyl)‐3‐methylimidazolium bromide (cyanoMIMBr), 1‐propyl‐3‐methylimidazolium bromide (propylMIMBr) and 1‐butyl‐3‐methylimidazolium chloride (butylMIMCl), were synthesised by microwave technology and fully characterised by mass spectrometry, thermogravimetric differential scanning calorimetry, thin layer chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopies. Cellulose and lignin were soluble in all three ILs with solubility being greatest in cyanoMIMBr. Regeneration of cellulose and lignin was achieved from saturated solutions of cellulose in IL and lignin in IL for all three ILs. The ILs propylMIMBr and butylMIMBr have been used for the first time in the separation and recovery of cellulose and lignin and regeneration of the IL from a mixture of cellulose and lignin in IL. FTIR analysis confirms successful recovery. CONCLUSIONS: This work demonstrates the ability of ILs to separate and recover cellulose and lignin from a mixed system. Copyright © 2009 Society of Chemical Industry     

Fabrication of a novel cellulose acetate imprinted membrane assisted with chitosan‐wrapped multi‐walled carbon nanotubes for selective separation of salicylic acid from industrial wastewater

Highly selective cellulose acetate (CA) blend imprinted membranes for salicylic acid (SA) removal were synthesized by phase inversion technique with chitosan as a functional polymer and chitosan‐wrapped multi‐walled carbon nanotubes (CHI‐wrapped MWCNTs) as the additives. The surface and cross‐sectional morphology of membranes were strongly affected by the amount of CHI‐wrapped MWCNTs. As compared to M₁‐MIM, M₂‐MIM, and M₄‐MIM, the M₃‐MIM with 2.0 wt % CHI‐wrapped MWCNTs showed higher membrane flux, faster kinetic, binding capacity and better selectivity for SA. The experimental data of adsorption kinetic were well fitted to the pseudo‐second‐order kinetic model by multiple regression analysis. The M₃‐MIM had the maximum adsorption capacity for SA. The selectivity coefficients of SA to p‐hydroxybenzoic acid (p‐HB) and acetylsalicylic acid (ASA) over M₃‐MIM were 6.3090 and 6.0019, respectively, showing that M₃‐MIM had excellent binding affinity and selectivity for separation of SA from SA‐contained aqueous solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42654.     

Properties and application of poly(acrylphenylamidrazone‐phenylhydrazide) chelating fiber for enrichment–separation of trace gold and ruthenium from solution samples

An ICP‐OES method using a new poly(acrylphenylamidrazone‐phenylhydrazide) chelating fiber to enrich and separate trace Au(III) and Ru(III) ions from solution samples is established. The results show that 50–500 ng/mL of Au or Ru ions can be enriched quantitatively by 0.1 g of the fiber at pH 4, with recoveries > 96%. The ions can be desorbed quantitatively with 10 mL of 4 M HCl and 3.0% CS(NH₂)₂ solution from the fiber column, with recoveries > 97%, and 200–1000‐fold excesses of Cu(II), Zn(II), Ca(II), Mg(II), Mn(II), Cr(III), Fe(III), Ba(II), and Al(III) caused little interference in the determination of these ions by ICP–OES. The chelating fiber can be reused eight times, and the recoveries are all > 95%. The relative standard deviations for enrichment and determination of 50 ng/mL of Au and Ru are in the range 1.8–1.9% (1.9% for Au and 1.8% for Ru). The recoveries of trace Au and Ru ions added to real waste water and alloy samples are 96–98%. The concentration of each ion found in the alloy samples was in good agreement with that provided by the plant. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2656–2660, 2001