pH levels over 12, as the stability of MOF is not strong in basic conditions. Also, it
was shown that the adsorption of arsenic take place in the interior of MOFs and not
on the exterior surface. This clarifies a higher adsorption limit of MOFs in contrast
with Fe 2 O 3 nanoparticles because it gives progressively inside space. Additionally,
MIL-53 (Fe) MOFs was utilized for arsenate removal and showed the higher
adsorption capacity (21.27 mg/g) than Fe-BTC (Vu et al. 2015). ZIF-8 (Zeolitic
imidazolate framework-8) was also examined to remove arsenic species and showed
the adsorption limits of 60.03 mg/g and 49.49 mg/g for As (V) and As (III),
respectively, (Jian et al. 2015).
6.9 Disposal of Metal ion Contaminated Materials
The nanomaterials may require disposing when their absorption limit is saturated.
For different metals and organics adsorbed nanoparticles, it might be recuperated
through burning (Mohan and Pittman 2007). But, for arsenic-adsorbed materials,
burning might not be perfect as oxide based arsenics are unpredictable and are
effectively discharged to the environment during the ignition procedure, that
makes another ecological hazard (Saiz et al. 2014). Hence, the most appealing
choice to deal with arsenic-adsorbed nanoparticles is to encapsulate through
stabilization-solidification process and transfer to safe landfill discarding
(Bystrzejewska-Piotrowska et al. 2009). The initial process, stabilizationsolidification, which is a mainstream strategy utilized to change over a possibly
dangerous liquids or solids into a non-dangerous waste materials before it goes to the
safe landfills (Leist et al. 2000).
6.10 Reusability
The economic situation is not favourable for the immediate disposal of hazardous
waste materials is expensive process, hence, regeneration and reusability of the
adsorbent is the favoured choice. Several investigations proposed that the greatest
adsorption limit of metal oxide based adsorbents remains practically steady after
multiple cycles of recovery and reuse (Tuutijärvi et al. 2012; Hu et al. 2005). Also,
pH is seemed to be a significant factor in the desorption process of arsenic from the
metal oxide adsorbents. The results showed the desorption qualities of As(V) and the
regeneration of the maghemite (γ-Fe 2 O 3 ) nanoparticle adsorbent (Tuutijärvi et al.
2012). 0.1 M NaOH alkaline solution demonstrated the most elevated desorption
productivity of 90% compare to other alkaline solution such as Na 2 CO 3 , Na 2 HPO 4 ,
NaOAc, and NaHCO 3 . Additionally, desorption was demonstrated to be influenced
by the concentration of alkaline and pH of the solution, for example, when the
concentration of NaOH was increased to 1M, complete desorption of As(V) was
accomplished.
6 Metal Oxides for Removal of Arsenic Contaminants from Water
183
was shown that the adsorption of arsenic take place in the interior of MOFs and not
on the exterior surface. This clarifies a higher adsorption limit of MOFs in contrast
with Fe 2 O 3 nanoparticles because it gives progressively inside space. Additionally,
MIL-53 (Fe) MOFs was utilized for arsenate removal and showed the higher
adsorption capacity (21.27 mg/g) than Fe-BTC (Vu et al. 2015). ZIF-8 (Zeolitic
imidazolate framework-8) was also examined to remove arsenic species and showed
the adsorption limits of 60.03 mg/g and 49.49 mg/g for As (V) and As (III),
respectively, (Jian et al. 2015).
6.9 Disposal of Metal ion Contaminated Materials
The nanomaterials may require disposing when their absorption limit is saturated.
For different metals and organics adsorbed nanoparticles, it might be recuperated
through burning (Mohan and Pittman 2007). But, for arsenic-adsorbed materials,
burning might not be perfect as oxide based arsenics are unpredictable and are
effectively discharged to the environment during the ignition procedure, that
makes another ecological hazard (Saiz et al. 2014). Hence, the most appealing
choice to deal with arsenic-adsorbed nanoparticles is to encapsulate through
stabilization-solidification process and transfer to safe landfill discarding
(Bystrzejewska-Piotrowska et al. 2009). The initial process, stabilizationsolidification, which is a mainstream strategy utilized to change over a possibly
dangerous liquids or solids into a non-dangerous waste materials before it goes to the
safe landfills (Leist et al. 2000).
6.10 Reusability
The economic situation is not favourable for the immediate disposal of hazardous
waste materials is expensive process, hence, regeneration and reusability of the
adsorbent is the favoured choice. Several investigations proposed that the greatest
adsorption limit of metal oxide based adsorbents remains practically steady after
multiple cycles of recovery and reuse (Tuutijärvi et al. 2012; Hu et al. 2005). Also,
pH is seemed to be a significant factor in the desorption process of arsenic from the
metal oxide adsorbents. The results showed the desorption qualities of As(V) and the
regeneration of the maghemite (γ-Fe 2 O 3 ) nanoparticle adsorbent (Tuutijärvi et al.
2012). 0.1 M NaOH alkaline solution demonstrated the most elevated desorption
productivity of 90% compare to other alkaline solution such as Na 2 CO 3 , Na 2 HPO 4 ,
NaOAc, and NaHCO 3 . Additionally, desorption was demonstrated to be influenced
by the concentration of alkaline and pH of the solution, for example, when the
concentration of NaOH was increased to 1M, complete desorption of As(V) was
accomplished.
6 Metal Oxides for Removal of Arsenic Contaminants from Water
183