Biosorption of manganese (II) and aluminium (III) ions from aqueous solution by immobilized Trichoderma asperellum BHU216

Removal of Al³⁺ and Mn²⁺ from solution by Trichoderma asperellum BHU216 immobilized on Irvingia gabonensis matrix in a batch system was investigated. Effect of biosorption conditions contact time, pH, bead size and spore load were studied. Equilibrium isotherms and re-usability of biosorbent were also determined. The result showed that optimum sorption of Mn²⁺ and Al³⁺ by immobilized sorbent was achieved at 7 mm bead size and 1.6 g l^-1 spore load. Optimum pH were 5 and 6 while equilibrium was attained at 120 and 180 mins for Mn²⁺ and Al³⁺ sorption respectively. Immobilized biosorbent was used in more than 5 batch cycles with over 50% removal achieved in 3 and 5 cycles for Al³⁺ and Mn²⁺ sorption. Brunauer-Emmett-Teller (BET) isotherm had the best-fit than both Langmuir and Freundlich isotherms for both metals (R² =0.98 and 0.92 for Mn²⁺ and Al³⁺ respectively). Manganese sorption proceeded at both surface and multi-layer levels with high sorption rates 18.88 mg/L and 19.72 mg l^-1, while aluminium sorption was feasible in a multi-layer process with low uptake (0.87 mg g^-1). This study showed that immobilized T. asperellum BHU216 can effectively act as biosorbent for Mn(II) and Al(III) sorption from solution.