Removal of Heavy Metal from Aqueous Solution by Magnesium Oxide Loaded Granular Activated Carbon

Joint Research on Environmental Science and Technology for the Eart

Preparation and characterization of activated carbons produced from oil palm empty fruit bunches

Activated carbons were prepared by activating oil palm empty fruit bunches (EFB) using various chemicals including H3PO4, KOH or ZnCl2 and were characterized by elemental analysis, nitrogen and methylene blue adsorption. The effect of the pre-treatment of EFB by NaOH was also investigated. Among all samples, EFB pre-washed with NaOH and then activated with ZnCl2 showed the greatest maximum adsorption capacity (357 mg/g) and BET specific surface area (1265 m2/g). The experimental data of all adsorbents were well fitted to the Langmuir isotherm model and pseudo-second-order kinetics model. This study demonstrated that ZnCl2 activation was the best way to obtain an activated carbon, and that NaOH pre-washing was effective as well for developing mesopores in EFB activated by H3PO4 and ZnCl2

Relationship between helium degassing of cattle-manure-compost adsorbents and copper ions removal

This work was aimed to investigate the effect of helium degassing of cattle-manure-compost (CMC) based activated carbons on the adsorptive removal of copper ions from aqueous solution. Degassing temperatures were 500°C, 800°C and 1000°C. Activated carbons were characterized according to surface chemistry and pore structures. Adsorption of copper ions was carried out using the conventional bottle-point technique to which the equilibrium data were correlated to Langmuir and Freundlich models. Results indicated that the uptake of copper ions could be well characterized by Langmuir model. It was found that the adsorption of copper ions decreased with significant decrease in surface area as a result of helium degassing at higher temperature. The increase of electron density on graphene layers offered higher affinity towards copper ions at lower equilibrium concentration. It was inferred that copper ions favorably adsorbed on mesopores at lower equilibrium concentration and switched to micropores at higher equilibrium concentration

Impacts of different extracellular polysaccharides on colony formation and buoyancy of

On the surface of Microcystis cells, there is a carbohydrate called extracellular polysaccharides (EPS) playing a significant role in the colony formation of Microcystis. EPS consists of tightly cell-bound EPS (TB-EPS), and both of these substances are considered to be strongly related to the colony formation and buoyancy of Microcystis. In this study, Microcystis aeruginosa (strain: NIES-843) was used to examine the effects of EPS, TB-EPS, and divalent metal cations such as calcium and magnesium on the buoyancy and colony formation of M. aeruginosa NIES-843. Under various light conditions, the addition of TB-EPS into the culture medium induced M. aeruginosa NIES-843 to obtain high buoyancy at concentrations of Ca2+ and Mg2+ concentrations of 10 mg/L and 30 mg/L, respectively. Under the absence of light, the addition of EPS could lead M. aeruginosa to form a colony and obtain buoyancy, and the addition of TB-EPS could not significantly change the buoyancy of M. aeruginosa NIES-843. The colony size analysis showed that at the same cationic concentration, the addition of TB-EPS could induce M. aeruginosa to form the largest colony and present strong buoyancy. This study suggested that temperature and illumination are conducive to colony formation and present higher buoyancy of M. aeruginosa.Tightly cell-bound extracellular polysaccharides (TB-EPS) enhanced colony formation of Microcystis aeruginosa NIES-843, which is strictly related to buoyancy. Microscope observation shows the colony induced by TB-EPS likes wild Microcystis. Temperature and light affected colony formation and buoyancy

Adsorption of aqueous metal ions on cattle-manure-compost based activated carbons

The objective of this study is to examine the suitability and performance of cattle-manure-compost(CMC) based activated carbons in removing heavy metal ions from aqueous solution. The influence of ZnCl(2) activation ratios and solution pH on the removal of Cu(II) and Pb(II) were studied. Pore texture. available surface functional groups, pH of point zero charge (pH(PZC)), thermogravimetric analysis and elemental compositions were obtained to characterize the activated carbons. Batch adsorption technique was used to determine the metal-binding ability of activated carbons. The equilibrium data were characterized using Langmuir, Freundlich and Redlich-Peterson models. It was found that the uptake of aqueous metal ions by activated carbons could be well described by Langmuir equation. It is suggested that the increase of surface area and mesopore ratio as a result of increasing activation ratios favored the removal of Cu(II), while activated carbon rich in acidic groups showed selective adsorption towards Pb(II). The preferable removal of Cu(II) over Pb(II) could be due to the rich nitrogen content as well as the higher mesoporous surface area in the CIVIC activated carbons. The impregnated CMC activated carbons also showed a better performance for Cu(II) removal at varying solution pH than Filtrasorb 400 (17400), while a similar performance was observed for Pb(II) removal