In this study, we investigated the ability of a magnetic wood biochar (WB)-based composite catalyst (Fe₃O₄–WB) to catalyze sodium persulfate (PS) for the remediation of estuary sediment contaminated with polycyclic aromatic hydrocarbons (PAHs). The effects of various critical parameters, including the catalyst dose and initial pH, were investigated. The degradation of the PAHs was found to be related to the number of rings in their structure. The results showed that Fe₃O₄–WB is an efficient catalyst for the removal of high-ring PAHs (HPAHs), with the highest degradation rates for the 6-, 5-, and 4-ringed PAHs being 90%, 84%, and 87%, respectively, for a PS concentration of 2 × 10⁻⁵ M, catalyst concentration of 3.33 g/L, and pH of 3.0. That the reduction rate of the HPAHs was greater than that of the low-ring PAHs can be attributed to the strong affinity of the HPAHs for biochar derived from wood biomass. Overall, this study revealed that the WB-mediated electron transfer catalysis of the surface functional groups in a wide range of pH in the Fe₃O₄–WB/PS system and potentially application in the remediation of sediments contaminated with PAHs.

In Taiwan, swine wastewater has become one of the major causes of the deterioration of surface water quality. The objective of this study was to evaluate the efficacy of using aquatic plant ecosystem to polish the treated swine wastewater. In this study, a hog farm was selected as the case study site. The daily wastewater of the studied farm was approximately 40 m³/d. Eichhornia crassipes was used as the aquatic plant for water polishment in the aquatic plant basin. Influent and effluent samples from each treatment unit were collected for water quality analyses. Results show that although the conventional three-stage system (solid separation followed by anaerobic and aerobic treatment) was effective to remove more than 97% of suspended solid (SS), ammonia nitrogen (NH₃-N), chemical oxygen demand (COD), and biochemical oxygen demand (BOD), BOD and COD in effluents still could not meet the discharge standards. The full-scale study shows that the aquatic plant ecosystem played an important role in the swine wastewater polishment and more than 27% of SS, NH₃-N, COD, and BOD, could be removed further from the effluents of the three-stage system, and the treated water could comply with the discharge standards and also meet the water reuse standards for irrigation and road washing. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analyses indicate that a variation in microbial diversity in the treatment system was observed. The system contained significant amounts of microbial ribospecies, which contributed to the carbon and nitrogen removal. DGGE results show that disappearance of E. coli was observed indicating that the system could remove E. coli and pathogens effectively. Results indicate that the aquatic plant ecosystem can be combined with the conventional three-stage treatment system to further polish the swine wastewater effluent.

This study uses the tree stumps of the three representative trees in Taiwan (Leucaena leucocephala, Syzygium samarangense, and Ziziphus jujuba) as the material source and recyclable oyster shell powder as an activator. A carbonization process for upgrading and recycling the tree stumps was developed with our homemade, digital-controlled, energy-saving carbonization system. First, the tree stumps are carbonized at a medium temperature of 500 °C and then heated to 900 °C for high-temperature carbonization, followed by the activation procedure as required. With our method, we can produce biochar with a high proportion of fixed carbon and a high proportion of meso- and macropores while maximizing the yield of wood vinegar. The specific surface area of the meso- and macropores can reach up to 70 m²/g or more. The effect of different activation materials on the pore characteristics and specific surface area of biochar was carefully examined. It was found that both KOH and oyster shell powder is the ideal activator for producing biochar with a high proportion of meso- and macropores. The FTIR spectrum, CEC, and contents of the ordinary elements and heavy metals of the biochar were also reported. It is clear from the FTIR data that the absorption peaks of the overall spectrum of the three types of biochar after carbonization at high temperature are cleaner than those of biochar carbonized at low temperature. This research can promote the recycling of agricultural residues, enhance soil carbon sequestration, preserve fertilizers, and suppress diseases and pests, moving towards approaching the goal of net-zero carbon emissions.

This study utilized two common macroalgae species from Taiwanese waters, green algae Ulva lactuca (Ulva) and red algae Sarcodia suae (Sarcodia), to evaluate the feasibility and efficacy of a novel cell wall disruption technique combining Fenton reagent and ultrasound-assisted extraction (UAE). The study analyzed protein characteristics, polysaccharide changes, and texture properties after pretreatment. Following cell wall disruption, the combined treatment of Fenton reagent and ultrasound significantly enhanced protein extraction yields, reaching 13.34 ± 0.50 % for Ulva and 3.96 ± 0.28 % for Sarcodia. In addition to increased yields, SDS-PAGE analysis and elevated free amino acid concentrations confirmed extensive protein degradation into low-molecular-weight peptides, indicating effective breakdown of protein structures. This enhanced degradation profile suggests that the pretreatment not only improves extraction efficiency but also promotes the production of functional protein hydrolysates. The surface hydrophobicity of the treated macroalgae significantly increased, while total and free sulfhydryl groups showed a decreasing trend, indicating that proteins were broken into smaller peptides, resulting in the destruction of sulfhydryl groups. To investigate the impact of the novel extraction technique on polysaccharides, the water-soluble total sugar and reducing sugar contents were measured. The disrupted Sarcodia samples showed total sugar and reducing sugar contents of 33.62 % and 2.76 mg/mL, respectively, while Ulva samples exhibited 27.00 % and 3.12 mg/mL, with significant increases observed in both macroalgae. Additionally, texture analysis and scanning electron microscopy (SEM) revealed that cell wall disruption enhanced the texture and compactness of the macroalgae. This study presents a high-efficiency cell wall disruption technique that effectively overcomes the challenges associated with macroalgae processing. By providing a robust scientific foundation, the research highlights the potential of macroalgae as valuable resources for food processing and plant-based meat production, while simultaneously contributing to sustainable practices and supporting efforts to reduce carbon emissions.