In this work, the cocoa pod husk (CPH) was converted into biochar products at higher carbonization temperatures (i.e., 400–800 °C). The pore and chemical properties of the resulting biochars and its post-leaching biochars by acid washing, including specific surface area, total pore volume, pore size distribution, true density, and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and Fourier Transform infrared spectroscopy (FTIR) were studied. Based on the pore properties, pyrolysis temperature at around 800 °C seemed to have the most profound impact on the pore development for producing biochar, where its Brunauer–Emmet–Teller (BET) surface area is 101 m²/g. More noticeably, more pores in the CPH-based biochar could be significantly created during the acid-washing, resulting in an increase of BET surface area from 101 to 342 m²/g. According to the data on the EDS and FTIR, the resulting biochars seemed to have oxygen-containing functional groups on the surface. Furthermore, the methylene blue (MB) adsorption performance of the optimal biochar product with maximal BET surface area was tested to fit its kinetics by the pseudo-second order model, showing a strong interaction between the biochar adsorbent and the cationic adsorbate.

In this work, the Honduras Mahogany (Swietenia macropnylla King, SMK) seed husk was used as a novel biomass resource for producing activated carbon by physical activation. The texture characteristics and chemical characterization of resulting products were investigated in correlation with the process parameters. Based on the thermochemical properties of the SMK biomass, the process conditions were set to a rate of about 10 °C/min under nitrogen (N₂) flow of 500 cm³/min heated to 500 °C, then switched to carbon dioxide (CO₂) flow of 100 cm³/min in the specified activation conditions (i.e., temperature of 700–850 °C for holding times of 0–60 min). Our findings showed that the texture characteristics (i.e., surface area and pore volume) increased with an activation temperature increase from 700 to 800 °C for a holding time of 30 min but gradually decreased as the temperature increased thereafter. Similarly, the texture characteristics also indicated an increasing trend with the residence time extending from 0 min to 30 min but slightly decreased as the time was extended to 60 min. Therefore, the optimal activation conditions for producing SMK-based activated carbon should be set at 800 °C for a holding time of 30 min to obtain the maximal texture characteristics (i.e., BET surface area of 966 m²/g and total pore volume of 0.43 cm³/g). On the other hand, the chemical characteristics were analyzed by energy dispersive X-ray spectroscopy (EDS) and Fourier Transform infrared spectroscopy (FTIR), showing oxygen complexes contained on the hydrophilic surface of the resulting activated carbon.

The edible mushroom industry has grown significantly in recent years due to the dietary change and the demand for heathy food. However, the spent mushroom compost (SMC) will be produced in large quantities after the harvest, thus forming an agricultural waste requiring proper management other than dumping or burning. In this work, two types of SMCs with the cultivation of shiitake fungus (SF) and black fungus (BF) were converted into porous biochar products (a series of SMC-SF-BC and SMC-BF-BC) at higher pyrolysis temperatures (i.e., 400, 600 and 800 °C) based on their thermochemical characteristics, using thermogravimetric analysis (TGA). The pore and chemical properties of the resulting products, including surface area, pore volume, average pore size, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier Transform infrared spectroscopy (FTIR), were studied to correlate them with the most important process parameter. The results showed that the pore properties of the biochar products indicated a significant increase with the increase in the pyrolysis temperature from 400 to 600 °C. The data on the maximal Brunauer-Emmett-Teller (BET) surface area for the biochar products produced at 800 °C (i.e., SMC-SF-BC-800 and SMC-BF-BC-800) were found to be 312.5 and 280.9 m²/g, respectively. Based on the EDS and FTIR, plenty of oxygen-containing functional groups were found on the surface of the resulting biochar products.

In this work, pineapple peel (PP) was reused as a precursor in biochar (BC) production at elevated temperatures (i.e., 500–900 °C) for residence times of 0–60 min. The findings showed that pyrolysis temperature and residence time played a vital role in pore development. As pyrolysis temperature increased from 800 to 900 °C for residence times of 20 and 60 min, the data on the Brunauer–Emmett–Teller (BET) surface area of the resulting biochar products significantly jumped from 11.98–32.34 to 119.43–133.40 m²/g. In addition, there was a significant increase in the BET surface area from 1.02 to 133.40 m²/g with the residence time of 0 to 20 min at 900 °C. From the data of the nitrogen adsorption–desorption isotherms and the pore size distribution, both micropores (pore diameters of <2.0 nm) and mesopores (pore diameters of 2.0–50.0 nm) are present in the PP-based biochar products. Due to its good fittings in the pseudo-second-order model and its hydrophilic nature, as seen in the Fourier transform infrared spectroscopy (FTIR), the resulting biochar could be a porous material to be used for the effective removal of cationic compounds (i.e., methylene blue (MB)) from liquid phases.

Fluorinated greenhouse gases (F-gases), including hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), and nitrogen trifluoride (NF₃), are used in a variety of applications, but they are potent greenhouse gases (GHGs). Therefore, they have been blanketed into the list of items to be phased out under international protocols or treaties. During the desk research, the updated statistics of Taiwan’s National Inventory Report (NIR) were used to analyze the trends of F-gases (i.e., HFCs, PFCs, SF₆, and NF₃) emissions during the period of 2000–2020. Furthermore, the regulatory strategies and measures for the reduction of the four F-gas emissions will be summarized to be in accordance with the national and international regulations. With the rapid development in the electronics industry, the total F-gas emissions indicate a significant increase from 2462 kilotons of carbon dioxide equivalents (CO_2eq) in 2000 to the peak value (i.e., 12,643 kilotons) of CO_2eq in 2004. However, it sharply decreased from 10,284 kilotons of CO_2eq in 2005 to 3906 kilotons of CO_2eq in 2020 due to the ongoing efforts of the regulatory requirements and the industry’s voluntary reduction in time sequence. It was also found that the most commonly used method for controlling the emissions of F-gases from the semiconductor and optoelectronic industries in Taiwan is based on the thermal destruction-local scrubbing method.

In recent years, the rapid economic development in Taiwan has resulted in greater complexity in handling industrial hazardous waste. The main aim of this paper was to present a trend analysis of the online reported amounts of industrial hazardous waste from the official database over the past decade (2010–2020). In addition, this study focused on the environmental policies and regulatory measures for the mandatory material resources from industrial hazardous waste according to the promulgation of the revised Waste Management Act. It was found that the annual reported amounts of industrial hazardous waste ranged from 1200 thousand metric tons to 1600 thousand metric tons, reflecting a balanced relationship between the industrial production and waste management. Based on the principles of resource recycling and circular economy, some case studies for specific types of industrial hazardous waste (including spent acid etchant, spent pickling liquid, and spent dimethyl formamide-contained liquid) were compiled to echo the government efforts in sustainable material management. In Taiwan, recycling amounts in 2020 were recorded up to 92,800, 130,460, and 54,266 metric tons, respectively. It was suggested to be a successful circular economy model in the printed circuit boards, steel/iron processing, and synthetic leather industries. In order to effectively reduce the environmental loadings and conserve material resources from industrial hazardous waste, some recommendations were also addressed to provide for the policy makers, environmental engineers and process manager.