Study On The Adsorption Of Dyes In Water By Mineral Materials Modified With Surfactants And Its Mechanism

The characteristics of dye wastewater are high concentration and chroma, complexcomposition and bad biological degradation ability. It makes the dye wastewate moredifficult to be treated. The study of dye wastewat is focus on the decolorization anddegradation of dyes.Attapulgite was modified with sodium dodecyl sulfate (SDS) to prepare SDS-attapulgite sorption material. CTMAB-13X adsorbent was obtained by13X molecularsieve modified with hexadecyl trimethyl ammonium bromide (CTMAB). Theadsorption capability of SDS-attapulgite for auramine and the adsorption capability ofCTMAB-13X for methyl orange was investigated under different conditions. Theadsorbents were characterized by SEM，FTIR，XRD and Zeta-Potential. The purposewas to investigate the adsorption performance and adsorption mechanism.Attapulgite exhibited a parallel aggregates of fibrous structure. Compared witnattapulgite, fibers were found to be interknitted resembling a woven texture inSDS-attapulgite and the structure of individual fibers was looser. In addition, theparticle size of SDS-attapulgite was smaller and the specific surface area was larger.These changes would result in stronger adsorption capacity of SDS-attapulgite. Theremoval rate for auramine was increased to80.2%from59.3%of attapulgite. Theadsorption capacity of SDS-attapulgite was275mg/g. There existed less aggregation inCTMAB-13X than in13X molecular sieve.13X molecular sieve was grafted withCTMAB and structure of13X molecular sieve remained intact after modification. Theremoval rate and adsorption capacity of CTMAB-13X for methyl orange reached88.9%and275.0mg/g respectively.After being desorbed thermally, SDS-attapulgite and CTMAB-13X wereregenerated and could be used again. In addition, SDS-attapulgite and CTMAB-13Xwere granulated and performed a column adsorption. The result showed that theremoval rate for auramine and methyl orange reached81.4%and86.0%respectively.The adsorption effect of activated carbon was inferior to SDS-attapulgite andCTMAB-13X. The adsorption capacity of activated carbon for auramine and methylorange were only129.6mg/g and182.0mg/g respectively. Furthermore, compared withmineral materials modified, the cost of activated carbon is higher and the regeneration are more difficult. Hence, the inorganic mineral materials modified with surfactants arenew adsorption materials with potential applications.