Sorption of malachite green (a cationic dye) and heavy metals by dead biomass of Phormidesmis molle (cyanobacteria)-dominated mat

Abstract

The test mat biomass rapidly sorbed malachite green (MG; a cationic dye) and heavy metals from mono-component, binary and ternary systems. In mono-component system, the sorption of Cu, Cd and MG increased when pH was increased from 3 to 4. However, in binary and ternary systems sorption of metals and MG were not substantially influenced by pH within the range 3–5. The presence of Cu or MG in binary or ternary systems reduced the sorption of each other from the solution. However, Cd enhanced the sorption of MG from binary solution and vice versa. Moreover, the ability of mat biomass to rapidly sorb metal ions and malachite green from mono-component, binary and ternary systems, together with easy harvesting of biomass due to self-immobilized nature, make it a suitable sorbent for the treatment of wastewaters that concomitantly bear the both heavy metals and dyes as pollutants.