Comparative study of the adsorption/immobilization of Cu by turmeric residues after microbial and chemical extraction

The turmeric industry produces a huge amount of residues annually. After undergoing different extraction process, turmeric residue biomass may be transformed from waste to resource. Turmeric residues exhibit different characteristics suitable for various environmental applications. In this work, the adsorption of Cu(II) onto turmeric residues from microbial (TR-A) and chemical (TR-B) extraction was investigated. The characteristics of the residues were examined via Brunauer-Emmett-Teller analysis, thermogravimetric analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and elemental analysis. Then, applications to Cu(II) immobilization were identified. Results suggested that although TR-B had better thermal stability, larger surface area, and more pores than TR-A, the adsorption capacity of Cu(II) onto TR-A was higher (13.12 mg/g) than that onto TR-B (7.37 mg/g) because TR-A had more microbial cell debris, metabolites, and S element than TR-B. In practice, TR-A-added soil achieved 40% more Cu immobilization than TR-B-added soil under continuous leaching of simulated acid rain. Consequently, the residues extracted using the microbial method prevented pollution after the traditional extraction process and transformed waste into a material for environmental remediation.

Pyrolysis of agricultural biomass residues: Comparative study of corn cob, wheat straw, rice straw and rice husk

Pyrolysis studies on conventional biomass were carried out in fixed bed reactor at different temperatures 300, 350, 400 and 450°C. Agricultural residues such as corn cob, wheat straw, rice straw and rice husk showed that the optimum temperatures for these residues are 450, 400, 400 and 450°C respectively. The maximum bio-oil yield in case of corn cob, wheat straw, rice straw and rice husk are 47.3, 36.7, 28.4 and 38.1wt% respectively. The effects of pyrolysis temperature and biomass type on the yield and composition of pyrolysis products were investigated. All bio-oils contents were mainly composed of oxygenated hydrocarbons. The higher area percentages of phenolic compounds were observed in the corn cob bio-oil than other bio-oils. From FT-IR and ¹H NMR spectra showed a high percentage of aliphatic functional groups for all bio-oils and distribution of products is different due to differences in the composition of agricultural biomass.