Adsorption and removal of dye Acid Red B from wastewater by lignite
褐煤对废水中酸性红B的吸附去除

Lignite was used as a cheap adsorbent to remove dye Acid Red B from simulated wastewater.Batch experiments were carried out to study the kinetics equation,isotherm,as well as the affecting parameters such as pH,dosage of lignite and ionic strength.The results indicated that the kinetics of the adsorption of Acid Red B on lignite followed the pseudo-second-order rate expression(R2=1.000),which demonstrated that sorption mechanism was the formation of chemical bond.The adsorption isotherm was proven to fit the Langmuir equation properly(R2=0.986),and the maximum adsorption capacity reached 42 mg/g.Adsorption of Acid Red B on lignite was affected by pH significantly.The removal rate of the dye from simulates wastewater increased with the reduction of pH,at pH=1,the removal rate reached the highest value(100%).This demonstrates that the adsorption may involve valence forces and electrostatic attraction between Acid Red B and lignite.The removal rate of the dye increased with the increase of the dosage of lignite under some conditions.The adsorption capacity also increased with the addition of ionic strength(NaCl).All these show that lignite can be used as an economic adsorbent in treatment of wastewater containing dyes.