Ni(II) immobilization by bio-apatite materials: Appraisal of chemical, thermal and combined treatments

Animal bones are natural and rich source of calcium hydroxyapatite (HAP), which was found to be a good sorbent material for heavy metals and radionuclides. Various treatments can reduce the content of bone organic phase and improve sorption properties. In this study, sorption capacities of raw bovine bones (B) and samples obtained by chemical treatment with NaOH (BNaOH), by heating at 400 oC (B400) and by combined chemical and thermal treatment (BNaOH+400), were compared, using Ni(II) ions as sorbates. Maximum sorption capacities increased in the order B<BNaOH<B400<BNaOH+400. Based on different sorption data and FT-IR analyses, the mechanism of Ni(II) sorption was found to be complex, with participation of both HAP and organic phase (when present). Sequential extraction analysis was applied for testing the stability of Ni(II) ions sorbed by BNaOH+400. Majority of Ni(II) was found in residual phase (65%) at lower level of sorbent loading, while with the increase of sorbent saturation carbonate fraction became dominant (39 %). According to the results, BNaOH+400 can be utilized in water purification systems. As an apatite based material with low organic content and high efficiency for Ni(II) sorption, it is also a good candidate for in-situ soil remediation, particularly at lower contamination levels.

Lead Contamination In Soil Of Yogyakarta City, Indonesia

This paper investigates on Pb concentrations and mobility in soil of overall Yogyakarta City, Indonesia. The objectives of this study include to investigate Pb concentrations in the surface soil throughout Yogyakarta and to study their possible sources and potential environmental impacts. The soil samples from 168 locations in Yogyakarta was obtained, representing different land use and traffic conditions. Spatial analysis and sequential extraction analysis were performed. Generally, contour pattern of Pb value clearly shows that high value is concentrated in the middle and few north part of the study area, confirmed by traffic condition in the study area. In general, the results of sequential extraction analysis shows that Pb was predominantly associated with exchangeable fraction. The presence of lead in the exchangeable fractions may pose a serious environmental concern since they are highly soluble and potentially bio-available in the soil of study area. Keywords: Soil, lead contamination, GIS, sequential extraction.

Comparison of nickel speciation in workplace aerosol samples using sequential extraction analysis and X-ray absorption near-edge structure spectroscopy

XANES and Zatka speciation methods were compared for application in epidemiology of occupational aerosols from sulphidic nickel production.

Effect of pH on phosphorus, copper, and zinc elution from swine wastewater activated sludge

With the goal of reducing the amounts of phosphorus (P), copper (Cu), and zinc (Zn) discharged from swine wastewater activated sludge treatment facilities, we studied the elution of these elements from activated sludge at various pH values. Sludge samples with neutral pH collected from three farms were incubated at pH values ranging from 3 to 10. The soluble concentrations of these elements changed dramatically with pH and were highest at pH 3. We assumed that P present in the sludge under neutral and alkaline conditions was in insoluble form bound up with magnesium (Mg) and calcium (Ca), because Ca and Mg also eluted from the sludge at low pH. To clarify forms of Zn and Cu in the sludge, we performed a sequential extraction analysis. Zinc in adsorbed, organically bound, and sulfide fractions made up a large proportion of the total Zn. Copper in organically bound, carbonate, and sulfide fractions made up a large proportion of the total Cu. The soluble P concentrations were lowest at pH 9 or 10 (11–36 mg/L), the soluble Zn concentrations were lowest at pH 8 or 9 (0.07–0.15 mg/L), and the soluble Cu concentrations were lowest at pH 6–9 (0.2 mg/L, the detection limit).