Novel chitosan-modified biochar prepared from a Chinese herb residue for multiple heavy metals removal: Characterization, performance and mechanism.

In this study, the sorption properties of Cr(VI), As(III), and Pb(II) on chitosan-modified magnetic biochar (CMBC) derived from residues of Ligusticum chuanxiong Hort. were investigated. CMBC was found to be a valuable material for removing three heavy metals from water simultaneously. Kinetic analysis suggested Cr(VI), As(III), and Pb(II) were chemisorbed onto CMBC, while isotherm data conformed well to Langmuir model, the maximum adsorption capacity of CMBC was found to be 65.74 mg/g for Cr(VI), 49.32 mg/g for As(III), and 69.45 mg/g for Pb(II). Experiments, characterization, and density functional theory (DFT) calculations were employed to explore the mechanisms. Furthermore, CMBC demonstrated excellent removal rates of over 95% for Cr(VI), 99% for As(III) and Pb(II) from contaminated water bodies. This work shows that CMBC holds significant potential for wastewater treatment of heavy metals and provides an effective solution for the utilization of Chinese herb residues in environmental remediation.

A comprehensive investigation on the chemical diversity and efficacy of different parts of Ligusticum chuanxiong.

Ligusticum chuanxiong Hort. (CX) is a medicinal and edible plant with a wide range of constituents of biological interest. Since the biomass of the non-medicinal parts of CX is huge, discarding them will cause a waste of resources. To expand the medicinal uses of CX, we comprehensively investigated the chemical diversity and efficacy of its different parts (rhizomes, fibrous roots, stems and leaves). 75 compounds in the volatile oil and 243 compounds in the methanol extracts (including 95 phthalides) obtained from CX were characterized by GC-MS and UHPLC/Q-Orbitrap MS analysis, respectively. Of 95 phthalides, 14 potential new compounds and 5 phthalide trimers were identified from CX for the first time. Phthalide monomers were more abundant in rhizomes and fibrous roots, and phthalide dimers or even phthalide trimers mainly in stems and leaves. By multivariate and univariate analyses, 22 and 24 different compounds were found in the volatile oils and the methanol extracts, respectively. In the bioactivity evaluation of different parts, stems and leaves showed the best antioxidant activity, fibrous roots showed the strongest vasodilator activity, and rhizomes showed the most significant anticoagulant activity, which was related to the different metabolites in different parts. Ultimately, this work revealed the similarities and differences of phytochemicals and bioactivities in different anatomical parts of CX. It might provide helpful evidence for the rational application of non-medicinal resources.