The objective of this study was to evaluate the adsorption of tetracycline (TC) on the Pinus taeda-derived activated biochar (BC). After NaOH activation, the well-developed porous surface structure was observed with a significantly increase in surface area (959.9 m/g). The kinetic and isotherm studies indicated that hydrogen bonding and π-π interaction on the heterogeneous surface would be the possible mechanisms, while intra-particle diffusion was considered as the major limitation for the adsorption of TC on the activated BC. The maximum adsorption capacity of the activated BC (274.8 mg TC/g BC) was higher than those of various activated BCs from the previous studies while it was similar to those of commercial activated carbons. It indicated that the activated BC had the high potential for TC removal in water.

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In the present work, the corrosion inhibition properties of three amino acid compounds, glycine (Gly), 2,2′-azanediyldiacetic acid (IDA), 5-aminopentanoic acid (5-APA), and two triazine (Tris) derivatives containing Gly or IDA units were investigated. It was found that the amino acids and their triazine derivatives behaved like mixed-type corrosion inhibitors that reduced oxidative dissolution and retarded a hydrogen emission reaction. In the case of the three amino acids, it was found that the increase in the length and the number carboxylic acid groups of the molecules enhanced the corrosion inhibition properties. It was also observed that the presence of triazine ring enhanced the corrosion inhibition properties significantly. It was suggested that the adsorption of triazine derivatives on a metal surface was the Langmuir isotherm adsorption and mainly physisorption. In the case of Tris-IDA, the six acetic acid moieties emanating from the triazine ring led to partial negative charges on the outer layer and disrupted the physisorption and chemisorption of Tris-IDA on the metal surface. In addition, two acetic acid moieties per IDA caused steric hindrance when Tris-IDA adsorbed onto the metal surface. These results made the corrosion inhibition properties of Tris-IDA lower than those of Tris-Gly.

We discuss trends in residual stress as a function of film thickness, growth temperature, and substrate orientation for GaN/AlN/6H-SiC heterostructures. Films are mostly compressive for samples less than about 0.7 m thick, are tensile up to about 2 m, then abruptly become less tensile with stress values near 1 kbar thereafter. We interpret this as a successive relief of lattice mismatch and thermal stresses culminating in a catastrophic relief by unknown mechanisms at moderate thicknesses. These data indicate that relaxation processes in these heterostructures are not as well understood as previously supposed.

The adsorption of sulfamethoxazole (SMX) onto a NaOH-activated pine wood-derived biochar was investigated via batch experiments and models. Surprisingly, the maximum adsorption capacity of activated biochar for SMX (397.29 mg/g) was superior than those of pristine biochars from various feedstock, but comparable to those of commercially available activated carbons. Elovich kinetic and Freundlich isotherm models revealed the best fitted ones for the adsorption of SMX onto the activated biochar indicating chemisorptive interaction occurred on surface of the activated biochar. In addition, the intraparticle diffusion limitation was thought to be the major barrier for the adsorption of SMX on the activated biochar. The main mechanisms for the activated biochar would include hydrophobic, π-π interactions and hydrogen bonding. This was consistent with the changes in physicochemical properties of the activated biochar (e.g., increase in sp 2 and surface area, but decrease in the ratios of O/C and H/C).