Design Phosphate Removal Technology using Volcanic Rocks: Kinetics and Equilibrium Studies

Fetene, Yohannis; Tegegn, Melaku; Alemayehu, Esayas

doi:10.17577/ijertv4is120093

Cited by 1 publication

(1 citation statement)

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“…However, except adsorption, most of these methods involve high capital cost with recurring expenses, which are not suitable for many parts of the world [15][16][17][18]. Several adsorbents have been investigated in various studies for the removal of phosphate from aqueous solution such as nanoparticles [19,20], nanoscale zero-valent materials [21], activated red mud [22], biogenetic calcium carbonate minerals [23], hybrid impregnated polymeric sorbent containing hydrated ferric oxide [24], industrial acidified laterite by-product [25], mixture of sand and dolomite [26], slag and fly ash [27], steel slags [28], silicate hybrid materials [29], schwertmannite (which is ferric oxyhydroxide sulphate) [30], and volcanic rocks [31]. Nanoparticle clay mineral receives much more attention among the natural adsorbents due to the high specific surface area, high adsorption rates compared to other adsorbents, low toxicity, easy operation, and, to some extent, cost-effectiveness.…”

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confidence: 99%

Halloysite Nanotubes as Adsorptive Material for Phosphate Removal from Aqueous Solution

Saki

Alemayehu

Schomburg³

et al. 2019

Water

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In this study, we were aiming at testing halloysite nanotubes as an efficient adsorbent for the removal of phosphate from agricultural runoff. Adsorption of phosphate onto powder and granular form of halloysite nanotubes has been examined by using the classical batch method and diffusion experiments at room temperature. Different forms of halloysite nanotubes were investigated to explore the effect of structure on the adsorption of phosphate. The maximum adsorption efficiency was obtained for powder halloysite nanotubes (79.5%) and granular form (94.7%). It is believed that the pore space of the granular halloysite nanotubes accommodates phosphorus in addition to physico-chemically bound phosphate at surfaces. The pseudo-first order and pseudo-second order model fitted well the experimental kinetic data for both powder and granular form of halloysite nanotubes. The fit of the Freundlich isotherm model was superior as compared with the Langmuir approach, implying that the halloysite nanotubes are heterogeneous because of multiple surface groups and different pore structures. The two forms of halloysite nanotube tested have the abundant potential for removal of phosphate from agriculture runoff. Additional investigations at the pilot scale are, however, required to draw definite conclusions.

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