Biosorption of nickel and cadmium using Pachira aquatica Aubl. peel biochar.

This study aimed to assess the value of Pachira aquatica Aubl. fruit peels by exploring their applicability in the biosorption process for the removal of Ni(II) and Cd(II) metal ions. The Pachira aquatica Aubl. fruit peel biochar (PAB) was extensively characterized through various techniques, including proximate analysis, helium pycnometer, XRD, SEM, point of zero charge determination, zeta potential measurement, and Boehm titration. Subsequently, kinetic, isotherm, and thermodynamic batch biosorption studies were conducted, followed by column biosorption tests. The characteristics of PAB, including low moisture content, a neutral point of zero charge, porosity, an irregular and heterogeneous structure, a negatively charged surface, and the presence of functional groups, indicate its remarkable capacity for efficiently binding with heavy metals. Biosorption equilibrium time was achieved at 300 min for both ions, fitting well with a pseudo second-order kinetic model and Langmuir isotherm model. These data suggest that the biosorption process occurred chemically in monolayer. The column C presented an exhaust volume of 1200 mL for Ni(II) and 1080 for Cd(II) and removal of 98% and 99% of removal for Ni(II) and Cd(II), respectively. In summary, PAB demonstrates substantial potential as a biosorbent for effectively removing heavy metals, making a valuable contribution to the valorization of this co-product and the mitigation of environmental pollution.

Chemical Composition of Pyroligneous Acid Obtained from Eucalyptus GG100 Clone.

The present study aimed to characterize the chemical composition of pyroligneous acid (PA) obtained from slow pyrolysis of the clone GG100 of Eucalyptus urophylla × Eucalyptus grandis. The efficiency of extraction of organic compounds by using different solvents-dichloromethane (DCM), diethyl ether (DE) and ethyl acetate (EA)-was evaluated. Wood discs were collected and carbonized at a heating rate of 1.25 °C/min until 450 °C. Pyrolysis gases were trapped and condensed, yielding a crude liquid product (CLP), which was refined to obtain pure PA. Then liquid-liquid extraction was carried out. Each extracted fraction was analyzed by GC-MS and the chemical compounds were identified. Experimental results showed that a larger number of chemical compounds could be extracted by using DCM and EA in comparison to diethyl ether DE. A total number of 93 compounds were identified, with phenolic compounds being the major group, followed by aldehydes and ketones, furans, pyrans and esters. Higher contents of guaiacol, phenol, cresols and furfural seem to explain the antibacterial and antifungal activity shown by PA, as reported previously in the literature. Experimental data indicated that the organic phase extracted from GG100 PA consists of a mixture of compounds similar to liquid smokes regularly used in the food industry.