Showing items 1 - 2 of 2

Your selections:

Effect of pyrolysis conditions on bone char characterization and its ability for arsenic and fluoride removal

- Alkurdi, Susan, Al-Juboori, Raed, Bundschuh, Jochen, Bowtell, Les, McKnight, Stafford

  • Authors: Alkurdi, Susan , Al-Juboori, Raed , Bundschuh, Jochen , Bowtell, Les , McKnight, Stafford
  • Date: 2020
  • Type: Text , Journal article
  • Relation: Environmental Pollution Vol. 262, no. (2020), p.
  • Full Text: false
  • Reviewed:
  • Description: This study examined arsenite [As(III)], arsenate [As(V)] and fluoride (F−) removal potential of bone char produced from sheep (Ovis aries) bone waste. Pyrolysis conditions tested were in the 500 °C–900 °C range, for a holding time of 1 or 2 h, with or without N2 gas purging. Previous bone char studies mainly focused on either low or high temperature range with limited information provided on As(III) removal. This study aims to address these gaps and provide insights into the effect of pyrolysis conditions on bone char sorption capacity. A range of advanced chemical analyses were employed to track the change in bone char properties. As pyrolysis temperature and holding time increased, the resulting pH, surface charge, surface roughness, crystallinity, pore size and CEC all increased, accompanied by a decrease in the acidic functional groups and surface area. Pyrolysis temperature was a key parameter, showing improvement in the removal of both As(III) and As(V) as pyrolysis temperature was increased, while As(V) removal was higher than As(III) removal overall. F− removal displayed an inverse relationship with increasing pyrolysis temperature. Bone char prepared at 500 °C released significantly more dissolved organic carbon (DOC) then those prepared at a higher temperature. The bone protein is believed to be a major factor. The predominant removal mechanisms for As were surface complexation, precipitation and interaction with nitrogenous functional groups. Whereas F− removal was mainly influenced by interaction with oxygen functional groups and electrostatic interaction. This study recommends that the bone char pyrolysis temperature used for As and F− removal are 900 °C and 650 °C, respectively. © 2020 Elsevier Ltd
  • Description: This research was performed as a part of PhD research which was supported in part by the Iraqi Government and the Australian Research Training Program.

Naturally occurring potentially harmful elements in groundwater in makueni county, south‐eastern kenya : effects on drinking water quality and agriculture

- Gevera, Patrick, Cave, Mark, Dowling, Kim, Gikuma‐njuru, Peter, Mouri, Hassina

  • Authors: Gevera, Patrick , Cave, Mark , Dowling, Kim , Gikuma‐njuru, Peter , Mouri, Hassina
  • Date: 2020
  • Type: Text , Journal article
  • Relation: Geosciences (Switzerland) Vol. 10, no. 2 (2020), p.
  • Full Text:
  • Reviewed:
  • Description: Makueni County is located in the semi‐arid south‐eastern Kenya region characterized by unreliable rainfall and limited surface water resources. This necessitates a high reliance on groundwater for domestic and agricultural use. In this paper, we report on the physico‐chemical characteristics of 20 drinking water sources (boreholes, shallow wells, streams, and tap water) collected during the dry season (November 2018), the geochemical processes controlling their composition, and their suitability for drinking water and irrigation. Of all the physico‐chemical parameters analysed, the concentrations of total dissolved solids, hardness, electrical conductivity, magnesium, calcium, chloride, and fluoride exceeded the permissible drinking water limits set by both the World Health Organization (WHO) and Kenya Bureau of Standards (KEBS) in up to 55% of the samples. The dominant ions reflect the high salinity in the water that ranged from very high to extreme in up to 50% of samples. The northern region shows the highest concentrations of the dominant parameters. The water type is predominantly Ca‐Mg‐HCO3 with a trend to Ca‐Mg‐Cl‐ SO4. Rock weathering and evaporation are suggested to be the primary controls of groundwater geochemical characteristics. High salinity and fluoride, which are associated with reported undesirable taste and gastrointestinal upsets, as well as cases of dental fluorosis are some of the effects of consuming groundwater in the region. These two parameters can be attributed to the weathering of biotite gneisses, granitoid gneisses, migmatites, and basaltic rocks that occur in the area. The high salinity and alkalinity of most of the samples analysed, renders the water unsuitable for irrigation in the study area. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  • 1