Study on copper-containing wastewater treated by bio-modification of corn stalks.

In order to solve the copper ion pollution in water and the utilization of corn stalk, the Aspergillus niger was used as a modified microbial inoculum to produce bio-adsorbent by means of solid-state fermentation of corn stalk. The effect of adsorbent addition (0.05~0.30 g), initial solution pH (1.0~6.0)and initial concentration of Cu (Ⅱ)ions (10~200 mg·L-1)on the biosorption capacity of the Aspergillus niger-modified corn stalk (ACS)were investigated. The results indicated that the maximum biosorption capacity of ACS to the Cu (Ⅱ) ions was 33.6 mg·g-1, which was 2.65 times as many as the maximum biosorption capacity of the raw corn stalk (RCS). Comparing RCS and ACS by means of scanning electron microscopy (SEM)and fourier transform infrared spectroscopy (FT-IR),the results separately showed that ACS had rougher surface,and had more free hydroxyl and carboxyl groups, which explained the increase of Cu (Ⅱ)ions absorption. Biosorption kinetics and biosorption isotherm of ACS on Cu (Ⅱ)ions were investigated. The results indicated that biosorption process of Cu (Ⅱ)ions on ACS could reach biosorption equilibrium after 30 min, and the quasi-second-order kinetic biosorption model could describe the biosorption process effectively. The biosorption process was dominated by monolayer biosorption and was well fitted to the Langmuir equation. The results also showed that the modification of corn stalk using Aspergillus niger solid-state fermentation was a rapid resource treatment method for corn stalk.