Physicochemical Properties and Heavy‐Metal Leaching of Malaysian Sugar‐Refinery Pressmud
Maheera Mohamad, Khai Lin Chong, Che Azlan Taib, Mohamad Faizal Ahmad Zaidi, Md Abdul Kafi, Siti Nor Farhana Zakaria, Fatin Baherah Khusna YahyaABSTRACT
Pressmud is an organic‐rich residue generated during sugar refining, but integrated physicochemical and column‐leaching data for Malaysian refinery‐derived material remain limited. This study characterized Malaysian pressmud and evaluated heavy‐metal breakthrough to inform its potential, rather than demonstrated, use as a soil amendment. Natural moisture content, pH, organic and carbon contents, specific gravity, compaction behavior, permeability, cation exchange capacity (CEC), surface functional groups, and column‐leaching behavior were determined using relevant British Standard and ASTM procedures and Fourier‐transform infrared (FTIR) spectroscopy. The pressmud had a pH of 8.03, moisture content of 31.8%, organic content of 20.0%, carbon content of 16.5%, specific gravity of 1.8, CEC of 99.8 meq 100 g − 1 , and permeability of 1.84 × 10 − 5 cm s − 1 . The optimum moisture content was 29.50% at a maximum dry density of 1.168 Mg m − 3 . FTIR analysis indicated several oxygen‐containing and aliphatic functionalities. In duplicate column runs, the metals exhibited distinct breakthrough profiles; at pore volume 10, the plotted values showed the order Cr > Cu > Mn > Fe > Zn > Cd. These profiles are descriptive, and the proposed retention mechanisms remain literature‐based interpretations because metal speciation was not directly measured. The results provide a characterization baseline and do not demonstrate improved soil fertility or crop performance. Soil incubation, plant trials, total‐metal analysis, speciation, additional replication, and long‐term field monitoring are required before agronomic application rates can be recommended.