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Recently developed fabrication methods for inorganic patterns (such as laser printing and optical lithography) can avoid some patterning processes conducted by conventional etching and lithography (such as substrate etching and modulation) and are thereby useful for applications in which the substrates and materials must not be damaged during patterning. Simultaneously, it is also necessary to develop facile and economical methods producing inorganic patterns on various substrates without requiring a special apparatus while attaining the above-mentioned advantages. The present study proposes a reaction-based method for fabricating inorganic patterns by immersing substrates coated with a colloidal nanosheet into an aqueous solution containing inorganic precursors. Silica and TiO

Objective: The main purpose of this study was to examine the impacts of the pyrolysis temperature on the removal of pharmaceuticals (i.e., ibuprofen (IBF) and carbamazepine (CBZ)) using NaOH pre-treated biochars produced from pine sawdusts.Methods:Two different types of kinetic and isotherm models were applied to investigate the adsorption mechanisms of IBF and CBZ by the NaOH pre-treated biochars produced at 600℃ (PB-600) and 800℃ (PB-800). In addition, the removal efficiencies of IBF and CBZ by PB-600 and PB-800 were compared under various conditions (adsorbent doses: 5-40 mg/L; 20-160 mg/L; temperature: 15-45℃; ionic strength: 0-0.5 M) to assess their feasibility as an alternative adsorbent for the removal of pharmaceuticals. Results and Discussion:PB-800 could more effectively remove CBZ and IBF than PB-600 because of its larger specific surface area (PB-600 = 408.70 m2/g; PB-800 = 472.92 m2/g), pore volume (PB-600 = 0.336 cm3/g; PB-800 = 0.658 cm3/g), and pore size (PB-600 = 4.63 nm; PB-800 = 6.25 nm). The Langmuir isotherm was more suitable for adsorption of IBF by PB-600 and the Freundlich isotherm was well fitted to the adsorption of CBZ by PB-600 and adsorption of CBZ and IBF by PB-800. The adsorption of CBZ by PB-600 and PB-800 was not affected by temperature while the removal efficiency of IBF was decreased with increasing the temperature due to the increased repulsive interaction between IBF and the biochars. Furthermore, the effects of the ionic strength on the adsorption of IBF were more pronounced than that of CBZ due to the differences in the surface charge properties.Conclusions:The higher pyrolysis temperature can improve the physicochemical properties of the NaOH pre-treated pine sawdust biochars associated with the removal of the pharmaceuticals (i.e., CBZ and IBF). Moreover, the adsorption mechanisms of CBZ and IBF by the biochars were strongly influenced by their specific surface area, pore volume and pore size.

The adsorption of radioactive iodine, which is capable of presenting high mobility in aquatic ecosystems and generating undesirable health effects in humans (e.g., thyroid gland dysfunction), was comprehensively examined using pristine spent coffee ground biochar (SCGB) and bismuth-impregnated spent coffee ground biochar (Bi@SCGB) to provide valuable insights into the variations in the adsorption capacity and mechanisms after pretreatment with Bi(NO

This study explored the effects of peanut shell biochar (PSB) on the adsorption capacities of fungicides with and without successive chemical modifications, using KMnO4 and KOH (PSBOX-A), in order to provide a valuable understanding of their adsorption mechanisms and behaviors. To this end, the physicochemical properties of PSB and PSBOX-A were examined by using the Brunauer–Emmett–Teller method, Fourier transform infrared spectroscopy, and scanning electron microscopy with an energy dispersive X-ray spectrometer. The effects of temperature, ionic strength, and humic acids on the adsorption of fungicides, using PSB and PSBOX-A, were estimated through batch experiments. Furthermore, adsorption kinetics, isotherms, and thermodynamics were studied. The maximum adsorption capacities of fungicides by PSBOX-A were estimated to be more notable (Qmax of carbendazim = 531.2 μmol g−1, Qmax of pyrimethanil = 467.7 μmol g−1, and Qmax of tebuconazole = 495.1 μmol g−1) than PSB (Qmax of carbendazim = 92.6 μmol g−1, Qmax of pyrimethanil = 61.7 μmol g−1, and Qmax of tebuconazole = 66.7 μmol g−1). These findings suggest that successive chemical modification using KMnO4 and KOH could potentially be used to effectively fabricate PSB to remove fungicides in water-treatment processes.

In this study, the adsorption of herbicides using ground coffee residue biochars without (GCRB) and with NaOH activation (GCRB-N) was compared to provide deeper insights into their adsorption behaviors and mechanisms. The physicochemical characteristics of GCRB and GCRB-N were analyzed using Brunauer–Emmett–Teller surface area, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction and the effects of pH, temperature, ionic strength, and humic acids on the adsorption of herbicides were identified. Moreover, the adsorption kinetics and isotherms were studied. The specific surface area and total pore volume of GCRB-N (405.33 m2/g and 0.293 cm3/g) were greater than those of GCRB (3.83 m2/g and 0.014 cm3/g). The GCBR-N could more effectively remove the herbicides (Qe,exp of Alachlor = 122.71 μmol/g, Qe,exp of Diuron = 166.42 μmol/g, and Qe,exp of Simazine = 99.16 μmol/g) than GCRB (Qe,exp of Alachlor = 11.74 μmol/g, Qe,exp of Diuron = 9.95 μmol/g, and Qe,exp of Simazine = 6.53 μmol/g). These results suggested that chemical activation with NaOH might be a promising option to make the GCRB more practical and effective for removing herbicides in the aqueous solutions.

The single adsorption of radioactive barium (Ba(II)), cobalt (Co(II)), and strontium (Sr(II)) ions using pristine (SCWB–P) and chemically activated spent coffee waste biochars with NaOH (SCWB-A) were thoroughly explored in order to provide deeper insights into the changes in their adsorption mechanisms through alkaline chemical activation. The greater removal efficiencies of SCWB-A (76.6–97.3%) than SCWB-P (45.6–75.2%) and the consistency between the adsorptive removal patterns (Ba(II) > Sr(II) > Co(II)) and oxygen bond dissociation enthalpies (BaO (562 kJ/mol) > SrO (426 kJ/mol) > CoO (397 kJ/mol)) of radioactive species supported the assumption that the adsorption removal of radioactive species with spent coffee waste biochars highly depended on the abundances of O-containing functional groups. The calculated R2 values of the pseudo-first-order (SCWB–P = 0.998–0.999; SCWB-A = 0.850–0.921) and pseudo-second-order kinetic models (SCWB–P = 0.988–0.998; SCWB-A = 0.935–0.966) are evident that the physisorption mainly controlled the adsorption of radioactive species toward SCWB-P and the chemisorption played a crucial role in their adsorptive removal with SCWB-A. From the calculated intra-particle diffusion, isotherm, thermodynamic parameters, it can be concluded that the intra-particle diffusion and monolayer adsorption primarily governed the adsorption of radioactive species using SCWB-P and SCWB-A, and their adsorption processes occurred spontaneously and endothermically. The dominant adsorption mechanism of spent coffee waste biochars was changed from physisorption (ΔH° of SCWB-P = 21.6–29.8 kJ/mol) to chemisorption (ΔH° of SCWB-A = 42.4–81.3 kJ/mol) through alkaline chemical activation. The distinctive M-OH peak in the O1s XPS spectra of SCWB-A directly corresponding to the decrease in the abundances of O-containing functional groups confirms again that the enrichment of O-containing functional groups markedly facilitated the adsorption removal of radioactive species by chemisorption occurred at the inner and outer surfaces of spent coffee waste biochars.

This study investigated the competitive adsorption mechanisms of pharmaceuticals (i.e., naproxen, diclofenac, and ibuprofen) toward the pristine and NaOH-activated biochars from spent coffee wastes (SCW) in lake water and wastewater effluent. The kinetic and isotherm studies revealed that the improved physicochemical characteristics and physically homogenized surfaces of the pristine SCW biochar through the chemical activation with NaOH were beneficial to the adsorption of pharmaceuticals (competitive equilibrium adsorption capacity (Qe, exp): NaOH-activated SCW biochar (61.25–192.07 μmol/g) > pristine SCW biochar (14.81–20.65 μmol/g)). The adsorptive removal of naproxen (Qe, exp = 14.81–18.81 μmol/g), diclofenac (Qe, exp = 15.73–20.00 μmol/g), and ibuprofen (Qe, exp = 16.20–20.65 μmol/g) for the pristine SCW biochar showed linear correlations with their hydrophobicity (log D at pH 7.0: ibuprofen (1.71) > diclofenac (1.37) > naproxen (0.25)). However, their Qe, exp values for the NaOH-activated SCW biochar (naproxen (176.39–192.07 μmol/g) > diclofenac (78.44–98.74 μmol/g) > ibuprofen (61.25–80.02 μmol/g)) were inversely correlated to the order of their log D values. These results suggest that the reinforced aromatic structure of the NaOH-activated SCW biochar facilitated the π-π interaction. The calculated thermodynamic parameters demonstrated that the competitive adsorption of pharmaceuticals on the NaOH-activated SCW biochar compared to pristine SCW biochar occurred more spontaneously over the entire pH (5.0–11.0) and ionic strength (NaCl: 0–0.125 M) ranges. These observations imply that the NaOH-activated SCW biochar might be potentially applicable for the removal of pharmaceuticals in lake water and wastewater effluent.

In this study, the waste heat recovery performance of a hexagonal thermoelectric generator (TEG) was investigated experimentally. Based on the system configuration and dimensions, a total of 18 thermoelectric modules (TEMs) were used for thermal energy harvesting. The internal finned structures of the hexagonal TEG were placed on the inner surface of the exhaust gas channel, in consideration of the thermal resistance and friction factor, in order to augment the heat transfer from the exhaust gas to the thermoelectric modules (TEMs), under various operating conditions. The surface of the TEMs was positioned on the hexagonal-shaped exhaust gas channel surface, whereas the other surface of the TEMs was maintained cool by a set of coolers through which the engine coolant flowed. The coolant line was modified in order to induce a total coolant flow of 10 LPM at 353 K from a coolant controller to the hexagonal TEG. In this study, the assembled hexagonal TEG was installed in the middle of the exhaust gas pipe of the internal combustion engine manufactured for hybrid electric vehicles, and was used as the heat source. The waste heat recovery performance of the hexagonal TEG was evaluated by considering eight engine-operating conditions under which the automotive vehicles were most frequently driven. The output power of the hexagonal TEG tended to increase with the increase in engine speed and load, and ranged between 21.2 and 98.8 W, which corresponded to a conversion efficiency of ∼1.3–2.6%. An acceptable maximum pressure drop across the hexagonal TEG of ∼2.1 kPa was observed for the maximum exhaust gas flow rate condition.

This study rigorously investigated the adsorption behaviors and mechanisms of strontium ions (Sr2+) by the pristine and magnetic biochars prepared via the pyrolysis of pristine and FeCl3-pretreated spent coffee grounds (SCG). The FeCl3-pretreatment could magnetize successfully the pristine SCG biochars (magnetization value of pristine SCG biochars = 0.19 emu/g; magnetization value of magnetic SCG biochars = 8.99 emu/g) and improved substantially their specific surface area (pristine SCG biochars = 5.3 m2/g; magnetic SCG biochars = 431.7 m2/g) and total pore volume (pristine SCG biochars = 0.002 cm3/g; magnetic SCG biochars = 0.186 cm3/g). However, the removal efficiency of Sr2+ with the pristine SCG biochars (33.4–34.1%) was not significantly different from that with the magnetic SCG biochars (33.1–33.9%). The calculated kinetic parameters indicate that the adsorption of Sr2+ by the pristine and magnetic SCG biochars was governed by the chemisorption (R2 of the pseudo-first-order kinetic equation ≤ 0.602; R2 of the pseudo-second-order kinetic equation = 1.000). The higher R2 values of the Langmuir isotherm (R2 = 0.999) model compared to the Freundlich isotherm model (R2 ≤ 0.950) are evident that the monolayer adsorption mainly determined the adsorptive removal of Sr2+ with the pristine and magnetic SCG biochars. Moreover, the adsorption of Sr2+ using the pristine and magnetic SCG biochars was the spontaneous and endothermic process. These observations indicate that the FeCl3-pretreatment might offer a viable way to effectively recover the residual SCG biochars after the Sr2+ adsorption through the magnetic separation (recovery rate = 90%).

A compact thermoelectric generator is developed for waste-heat recovery in a sedan-type hybrid electric vehicle. The shape and dimensions of the thermoelectric generator are precisely determined by performing a series of theoretical analyses to meet spatial and maximum allowable pressure drop restrictions. The waste-heat recovery performance of the thermoelectric generator is experimentally evaluated using a hybrid electric vehicle engine under the nine most commonly experienced driving conditions. One surface of the thermoelectric modules is heated by the exhaust gas flow, whereas the other surface is cooled by the engine coolant flowing at 10 L/min and 353 K. A maximum power output of ~118 W and an energy conversion efficiency of ~2.1% are obtained using 12 thermoelectric modules under the engine operating conditions that led to the highest exhaust gas flow rate and temperature. The waste-heat recovery characteristics of the present thermoelectric generator are systematically analyzed, and the results corresponding to thermal energy flow and heat recovery efficiency, as well as the voltage output–current output and power output–load resistance curves, are presented.