Modified hardwood sawdust as adsorbent of heavy metal ions from water
The sawdust of oak and black locust hardwood was found to have good adsorption capacities for heavy metal ions. The leaching of coloured organic matters during the adsorption can be prevented by each of the following pre-treatments of adsorbents: with formaldehyde in acidic medium, with sodium hydroxide solution after formaldehyde treatment, or with sodium hydroxide only. The studies indicated that the leaching of coloured matters from modified hardwood sawdust was less than that from unmodified hardwood sawdust, namely between 70 and 94%, dependent on wood species and the method of modification. At the same time, adsorption capacities of modified adsorbents were higher than unmodified adsorbents when sodium hydroxide was applied for modification. When formaldehyde was applied for modification, the adsorption capacities of adsorbents remained unchanged. Only the application of sodium hydroxide was recommended for modification of hardwood sawdust.
KeywordsAdsorption Capacity Sodium Hydroxide Wheat Straw Sawdust Sodium Hydroxide Solution
The results are part of the Project No. 1775 “Development of methods for identification of toxic and cancerogenic pollutants in mass-cultures and procedures of their separation”, which is financially supported by the Ministry of Science, Technologies and Development of the Republic of Serbia.
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