Distinct interactions of pig and cow manure-derived colloids with TiO2 nanoparticles and their impact on stability and transport

Enhanced Transport of TiO2 in Unsaturated Sand and Soil after Release from Biodegradable Plastic during Composting

“…Further, the transport of the pristine TiO 2 was enhanced to a similar extent as the transport of the mulch-released TiO 2 (Figure D and Table S3), when the pristine TiO 2 particles cotransported with the compost residues. These results imply that the higher mobility of the mulch-released TiO 2 in the sand columns can be attributed to steric repulsion imposed by the presence of humic acid like substances in compost residues, consistent with previous studies. , …”

“…Similarly, Yang et al found that the blocking effect was accountable for the increased mobility of bacteria in sand columns preflushed with humic acid (1 mg L –1 ). Moreover, humic acid can promote colloid transport by adsorbing onto colloid surfaces and imposing steric interactions. , Indeed, the mulch-released TiO 2 particles appeared to be covered with compost residues (Figure S1A), and when steric interactions were included into the DLVO calculations, the energy barrier substantially increased between the TiO 2 particles and the sand–water interface (Figure S8C), suggesting unfavorable attachment conditions. Further, the transport of the pristine TiO 2 was enhanced to a similar extent as the transport of the mulch-released TiO 2 (Figure D and Table S3), when the pristine TiO 2 particles cotransported with the compost residues.…”

“…Further analysis with single-particle mass spectrometry (Figure 4) confirmed that the dislodged particles indeed contained TiO 2 particles, and the mass spectra of individual Ti-signaled particles matched those of pristine TiO 2 particles (Figure 4A). The majority of the released particles from the meshbags, however, was composed of compost material, as indicated by the dominance of 23 Na + , 27 Al + , 39 K + , and 44 SiO + /CO 2 + in the overall mass spectrum (Figure 4A, top panel). The size distribution of the released particles was similar to that of the pristine TiO 2 (Figure 4B).…”

Coupled impact of proteins with different molecular weights and surface charges on TiO2 mobility

“…To evaluate the influence of protein on the stability of TiO 2 , 25 mg L −1 TiO 2 suspension was prepared by ultrasonic bath for 30 min, which was mixed with certain concentrations (0, 2, 4, 8, and 16 mg L −1 ) of BSA in 1 mM NaCl solution or with 8 mg L −1 BSA, OVA, and A-LA in various IS (1, 5 and 10 mM). The absorbance ( A ) of TiO 2 with the protein mixture was monitored using a UV-vis spectrophotometer at a wavelength of 285 nm, 56 which was measured every 2 minutes during a 2 h duration.…”

“…The packing procedures of the quartz sand column were followed as described in previous studies. 56,57 About 95.5 g of clean quartz sand were wet-packed into a 12.4 cm long and 2.6 cm diameter stainless-steel column with a bulk density of 1.45 ± 0.02 g cm −3 and a porosity of 0.45 ± 0.01. The columns were flushed upward using a peristaltic pump (DHL-A, Huxi, China) at a flow rate of 1 mL min −1 .…”