Abstract: In order to solve the problems of cadmium ion pollution in water bodies and the resource utilization of solid waste based materials,wheat straw and boron sludge were mixed in equal amounts and calcined at 700 ℃ (nitrogen oxygen displacement) for 2 h to prepare composite biochar adsorption material ( BBm). Using BBm as adsorbent,simulated wastewater containing cadmium with a Cd2+ concentration of 200 mg / L was studied for adsorption. The results of the single-factor test results showed that with the increase of BBm dosage,solution pH,speed and adsorption reaction time,the removal rate of Cd2+ by BBm increased until the removal rate no longer increased after the adsorption equilibrium. The orthogonal test results showed that the strength of each factor was as following:solution initial pH value,BBm dosage,speed and reaction time,and 100 mL of simulated wastewater (the concentration of cadmium is 200 mg / L) was adsorbed for 180 min at room temperature ( about 25 ℃ ),BBm dosage of 0. 5 g,pH value of 8 and speed of 200 r / min,and a good index of removal rate of 99. 99% was obtained. The results of adsorption isothermal fitting showed that the adsorption process of BBm to Cd2+ was in line with the Langmuir isothermal adsorption model,and the quasi-secondary kinetic model could better fit the adsorption process.

Key words: heavy metal ions,wastewater containing cadmium,biochar,boron mud,adsorptio