Application and optimization of the combined use between C.
obtusifolia seed gum and alum in coagulation process were investigated
in this study. Based on the current findings, the combined use
of C. obtusifolia seed gum and alum tremendously reduced the optimal
dosage of coagulants by 90.5 and 62.5%, respectively. Without
adjusting the initial pH of raw PPME, 0.17 and 0.09 g/L of C. obtusifolia
seed gum and alum, respectively were required to achieve the
maximum treatment performance (89.6 and 55.4% of TSS and COD
removals, respectively) under slow-mixing time of 3.40 min.
The floc characteristics using both C. obtusifolia seed gum with
alum, revealed distinctive results on the presence of functional
groups and thermal stability of the floc. Based on the combined floc
morphology, possible coagulation mechanisms included adsorption
with inter-particle bridging and charge neutralization. The
present study successfully revealed that C. obtusifolia seed gum,
as an emerging plant-based coagulant, could be potentially used
as a coagulant substitute or coagulant aid together with alum in
treatment of raw industrial effluent like PPME.