en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:times new roman;"><strong>Background:</strong> Natural organic matters (NOMs) have the main role in formation of trihalomethanes. These compounds are in natural water sources due to biological activities. In the presented study, adsorption and separation of humic acid as an index of natural organic matters using multi-walled carbon nanotubes is evaluated.<br> <strong>Methods: </strong>The experiments were carried out in bath adsorption reactors with different concentrations of humic acid. The effects of pH, adsorbent dose, national concentrations of humic acid and contact time as study variables were tested in separated experiments, as well as, kinetic and isotherm models of the adsorption process were determined.<br> <strong>Results: </strong>The results showed that the adsorption follows Freundlich isotherm model and pseudo second-order kinetic equation. The removal percent of humic acid reached to higher than 90% with dosage of 1g/l of nanotube.<br> <strong>Conclusion: </strong>Adsorption of humic acid from water by multi-walled carbon nanotubes is an efficient alternative pretreatment method in water treatment plants.</span></span><br> &nbsp;</div> Adsorption, Nanotube, Humic acid, Water 253 260 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-39-3&slc_lang=en&sid=1 Zahra Abedi zmehr@zums.ac.ir 100319475328460010050 100319475328460010050 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Mohammad Reza Mehrasbi zmehr@zums.ac.ir 100319475328460010051 100319475328460010051 Yes Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Ali Assadi assadi@ zums.ac.ir 100319475328460010052 100319475328460010052 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.