Influence of seed maturity on the physicochemical characteristics and turbidity removal performance of sulfuric acid-modified Moringa oleifera biomass
Hidayatul Aini Zakaria, Nur Kamaliah Yusri, Nur Farizan Munajat, Hanis Mohd Yusoff, Fariza Hanim SuhailinABSTRACT
Three-stage summary: fresh and mature Moringa oleifera seeds, sulfuric acid treatment and carbonisation, then kaolin turbidity testing. Peak removal was 93.99% for mature and 93.50% for fresh biomass, a difference of 0.49 percentage points.
Biomass-derived adsorbents offer a low-cost, decentralized alternative to conventional coagulants for water treatment, but the influence of feedstock maturity on their performance remains largely unexamined. This study compared fresh and mature Moringa oleifera seeds, prepared under identical conditions, to determine whether seed maturity affects the physicochemical properties and turbidity removal performance of sulfuric acid-modified biosorbents. Seeds were impregnated with 0.6 M H2SO4 at biomass-to-solution ratios of 4–18% (w/v) for 2 or 4 h, then thermally treated at 400 °C for 2 h. The resulting materials were characterized by FTIR, XRD, and SEM, and evaluated for turbidity removal using a synthetic kaolin suspension. FTIR confirmed retention of oxygen-containing functional groups after acid treatment, with intensity declining after prolonged (4 h) impregnation; XRD showed both materials remained predominantly amorphous throughout, with no new crystalline phases forming. SEM revealed that both seed types developed rougher, more heterogeneous surfaces after treatment, though mature biomass formed a distinct layered fibrillar structure after 4 h while fresh biomass retained a porous, interconnected morphology. Turbidity removal peaked at an 11% (w/v) impregnation ratio and 4 h treatment, reaching 93.99% for mature biomass and 93.50% for fresh biomass, a difference small enough to indicate that impregnation duration, rather than seed maturity, was the dominant factor governing adsorbent performance. These findings suggest that seed maturity need not be a limiting consideration in the practical selection of Moringa oleifera biomass for sulfuric acid-modified water treatment applications.