Four　modifiers,　amorphous　iron　(hydr)oxides　(Fe-x(OH)(y)),　manganese　oxides　(MnxOy)　and　cationic　surfactants,　cetyltrimethylammonium　bromide　(CTMAB),　and　poly(dimethyldiallylammonium　chloride)　(PDMDAAC),　were　used　to　synthesize　single　and　complex　modified　bentonite.　Arsenic　removal　by　modified　bentonite　was　investigated　through　effects　of　the　type,　combination　and　adding　level　of　modifiers.　X-ray　powder　diffraction　(XRD),　scanning　electron　microscopy　(SEM)　and　N-2　adsorption-desorption　were　used　to　explore　the　characteristics　of　the　original　and　modified　bentonite.　It　was　found　that　the　type,　combination　and　adding　amount　of　modifiers　would　have　a　noticeable　influence　on　the　structure　and　adsorption　behavior　of　resulting　bentonite　adsorbents.　The　complex　modified　bentonite,　with　manganese　oxides　and　then　PDMDAAC　at　proper　addition　level,　showed　the　best　adsorption　properties　for　arsenic,　which　could　be　due　to　a　synergistic　effect　between　PDMDAAC　and　manganese　oxides　during　modification　process.　PDMDAAC　was　found　to　be　favorable　for　coating　of　manganese　oxides　onto　bentonite.　The　adsorbing　capacity　of　modified　bentonite　depended　not　only　on　specific　surface　area　(SSA),　but　mainly　on　composite　components　and/or　their　specific　surface　properties.　(C)　2015　Elsevier　B.V.　All　rights　reserved.