Na Ma

Adsorption equilibrium and kinetic studies of crystal violet and naphthol green on torreya-grandis-skin-based activated carbon

A new type of activated carbon, torreya-grandis-skin-based activated carbon (TAC), has been used to remove the harmful dyes (cationic dye crystal violet (CV) and anionic dye naphthol green (NG)) from contaminated water via batch adsorption. The effects of solution pH, adsorption time and temperature were studied. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and isotherm constant calculation. It was found that the maximum equilibrium adsorption capacities were 292mg/g and 545mg/g for CV and NG, respectively. Adsorption kinetics was verified by pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models. Results indicated that the rate of dye adsorption followed pseudo-second-order kinetic model for the initial dye concentration range studied. Temperature-dependent adsorption behavior of CV and NG shows that the adsorption is spontaneous and endothermic, accompanying an entropy increase. This work indicates that TAC could be employed as a low-cost alternative for the removal of the textile dyes from effluents.

Single and bicomponent anionic dyes adsorption equilibrium studies on magnolia-leaf-based porous carbons

A new type of porous carbon is prepared by cost-effective pyrolysis carbonization and subsequent alkali activation of an easily available biomass, magnolia leaf (ML). The as-prepared ML porous carbons (MPCs) show high specific surface areas and suitable pore size distributions. Surface characterization of ML and MPC-1 were investigated by N2 adsorption, FT-IR, SEM and TEM. Two anionic azo dyes were used, namely, orange II (OII) and methyl orange (MO), to simulate the textile effluent. Batch experiments of OII and MO in a single dye system (SDS) and a binary dye system (BDS) onto MPC-1 were investigated as a function of pH, contact time and species concentration. The adsorption process followed the Langmuir isotherm model with high coefficients of correlation (R2 > 0.999). The pseudo-second order kinetic model fitted well to the experimental results. This study indicates that MPCs demonstrated superior OII and MO adsorption capabilities and could be employed as a low cost alternative to commercially available porous carbon for the removal of dyes from wastewater.

Copper-containing porous carbon derived from MOF-199 for dibenzothiophene adsorption

A novel type of copper-containing porous carbon has been synthesized by filling the pores of MOF-199 hard template with furfuryl alcohol as carbon precursor, followed by carbonization and activation for the first time. The textural properties of the as-prepared carbon material were proven by examinations with XRD, SEM, TEM, ICP, XPS and N2 adsorption. The adsorption performance of dibenzothiophene in three types of model oils was investigated by batch tests. The equilibrium data was best represented by the Langmuir isotherm model, showing a maximum monolayer adsorption capacity of 59 μg g−1, which was much higher than some other adsorbents reported in the literature. Considering all the advantages, the as-prepared copper-containing porous carbon shows promising potential for practical deep desulfurization, especially for thiophenic compound removal.

The remarkable adsorption capacity of zinc/nickel/copper-based metal–organic frameworks for thiophenic sulfurs

A new type of Zn/Ni/Cu-BTC metal–organic framework (MOF) with three central metals (Cu2+, Zn2+ and Ni2+) and one organic ligand (1,3,5-benzene tricarboxylic acid, H3BTC) was synthesized and its adsorption performance for thiophene (Th), benzothiophene (BT) and dibenzothiophene (DBT) from three typical model oils was systematically studied using breakthrough curves. Due to its coordinatively unsaturated sites, Zn/Ni/Cu-BTC possesses a high sulfur capacity. In addition, it shows a strong durability in the presence of aromatic components and moisture. The saturated adsorbents could be easily regenerated with solvent washing and nitrogen sweeping. The results of this study revealed that Zn/Ni/Cu-BTC is a promising adsorbent for the removal of thiophenic sulfurs from fuels.

Competitive Adsorption of Dye Species onto Biomass Nanoporous Carbon in Single and Bicomponent Systems

We first present a cost-effective approach to simultaneously dispose of rutaceae plant waste (the discarded peels of orange, finger citron, pomelo and lemon) to yield biomass nanoporous carbons (BNCs). The adsorption of orange II (OII) and acid chrome blue K (ACBK) from aqueous solutions in single and binary dye systems by four types of BNCs were studied in a batch adsorption system. The adsorption studies include both equilibrium adsorption isotherms and kinetics. Four adsorption models for predicting the multicomponent equilibrium sorption isotherms have been compared in order to determine which one is the best fit model to predict or correlate binary adsorption data. The kinetic data were well described by the pseudo-second-order kinetic model. It was found that the adsorption capacity of orange peel-based nanoporous carbon (OPC) is much higher than those of the other types of BNCs. In addition, OPC also shows higher OII uptake capacities from binary dye solutions. The four types of BNCs could be employed as a low-cost alternative for the removal of textile dyes from effluents.

Facile synthesis of mesoporous calcium carbonate particles with finger citron residue as template and their adsorption performances for Congo red

Herein, we demonstrate a simple and cost-effective method to prepare the new hierarchically Ni-doped porous CaCO3 monoliths in a large scale by mineralizing finger citron residue templates with a calcium acetate precursor. The morphology, microstructure, and element composition of as-prepared adsorbents are characterized by Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), and N2 adsorption, respectively. Adsorption performance of anionic dye Congo red was investigated in a batch experiment. The results showed that pseudo-second-order kinetic model and Langmuir adsorption isotherm matched well for the Congo red adsorption. Compared with previously reported adsorbents, due to positive and negative charge effect between Congo red and Ni, Ni-doped porous CaCO3 monoliths demonstrated a superior Congo red dye adsorption capability. The results of the present study substantiate that Ni-doped porous CaCO3 monoliths is a promising adsorbent for the removal of the anionic dyes from wastewater.

Highly enhanced adsorption of congo red by functionalized finger-citron-leaf-based porous carbon

A novel high-performance porous carbon material, lanthanum(III)-doped finger-citron-leaf-based porous carbon (La/FPC), has been synthesized and used as an adsorbent for anion dye Congo red (CR). The La/FPC was characterized by nitrogen adsorption and desorption isotherms, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The adsorption performance of CR by the FPC and La/FPC composites with different contents of lanthanum(III) were evaluated in fixed-bed breakthrough experiments and batch tests at room temperature (298 K). The La/FPC had a high CR uptake capacity, which was superior to those previously reported for other adsorbents. The La/FPC sorbents can be easily regenerated using an ethanol elution technique, and after five cycles the reused La/FPC maintained about 98% of its original CR adsorption capacity. The adsorption kinetics of CR onto the lanthanum(III)-doped FPCs followed a pseudo-second-order kinetic model and fitted well with a Langmuir adsorption isotherm. La/FPC is a promising adsorbent for the removal of the anionic dyes from wastewater.