This　study　focused　on　the　adsorptive　behaviors　of　humic　acid　onto　freshly　prepared　hydrous　MnO2(s)　(δMnO2),　and　investigated　the　feasibility　of　employing　δMnO2　for　humic　acid　removal　from　drinking　water.　Effects　of　such　parameters　as　molecular　mass　of　humic　acid,　kinds　of　divalent　cations　on　adsorptive　behaviors　and　possible　mechanisms　involved　were　investigated.　This　study　indicated　that　humic　acid　with　higher　molecular　mass　exhibited　more　tendency　of　adsorbing　onto　δMnO2　than　that　with　lower　molecular　mass.　Ca2+　facilitated　more　humic　acid　adsorption　than　Mg2+;　UV-Vis　spectra　analysis　indicated　higher　capabilities　of　Ca2+　coordinating　with　acidic　functional　groups　of　humic　acid　than　that　of　Mg2+.　Additionally,　ζ　potential　characterization　indicated　that　Ca2+　showed　higher　potential　of　increasing　gz　potential　of　δMnO2　than　Mg2+.　Ca　2+　of　1.0　mmol/L　increased　ζ　potential　of　δMnO2　from　-37　mV　(pH　7.9)　to　+7　mV　(pH　7.2),　while　1.0　mmol/L　Mg2+　increased　to　lower　value　as　-9　mV　(pH　6.5),　correspondingly.　Fourier　transform　infrared　(FTIR)　spectra　demonstrated　the　adsorption　of　humic　acid　onto　δMnO2,　showing　the　important　roles　of-COO-　functional　groups　and　surface　Mn-OH　in　the　adsorption　of　humic　acid　onto　δMnO2.　©　Higher　Education　Press　2007.