Effects of Adsorbed F, OH, and Cl Ions on Formaldehyde Adsorption Performance and Mechanism of Anatase TiO₂ Nanosheets with Exposed {001} Facets

Formaldehyde (HCHO), as the main indoor air pollutant, is highly needed to be removed by adsorption or catalytic oxidation from the indoor air. Herein, the F^–, OH^–, and Cl^–-modified anatase TiO₂ nanosheets (TNS) with exposed {001} facets were prepared by a simple hydrothermal and post-treatment method, and their HCHO adsorption performance and mechanism were investigated by the experimental analysis and theoretical simulations. Our results indicated that the adsorbed F^–, OH^–, and Cl^– ions all could weaken the interaction between the HCHO and TNS surface, leading to the serious reduction of HCHO adsorption performance of TNS. However, different from F^– and Cl^– ions, OH^– ion could induce the dissociative adsorption of HCHO by capturing one H atom from HCHO, resulting in the formation of one formyl group and one H₂O-like group. This greatly reduced the total energy of the HCHO adsorption system. Thus, the adsorbed OH^– ions could provide the additional active centers for HCHO adsorption. As a result, the NaOH-treated TNS showed the best HCHO adsorption performance mainly because its surface F^– was replaced by OH^–. This study will provide new insight into the design and fabrication of high performance adsorbents for removing indoor HCHO and, also, will enhance the understanding of the HCHO adsorption mechanism

Predictors of time trade-off utility values from diabetic retinopathy patients and ophthalmologists, determined by multiple linear regression.

<p>TTO, time trade-off; CI, confidence interval; BCVA, best-corrected visual acuity; DR, diabetic retinopathy.</p><p>*Backward linear regression with <i>p</i> = 0.1 cut-off for exclusion was used.</p><p>Predictors of time trade-off utility values from diabetic retinopathy patients and ophthalmologists, determined by multiple linear regression.</p

Distribution of utility values from diabetic retinopathy patients and ophthalmologists.

<p>The utility values were measured by time trade-off and rating scale methods. Boxes indicate the 25^th to 75^th percentiles of the utility values distribution, e.g., the interquartile range, and the bars inside the boxes represent the median. The whiskers extend to the lower and the upper extremes defined as 25^th percentile minus 1.5 times the interquartile range and the 75^th percentile plus 1.5 times the interquartile range. 〇, mild outliers; *, extreme outliers.</p

Scatter plot of the position of minimum corneal thickness in the left eyes of 614 normal Chinese children.

<p>Along the verticat axis, a negative number represents the distance inferior to the pupil center, while a positive number represents the distance superior to the pupil center (μm). Along the horizontal axis, a negative number represents the distance temporal to the pupil center, while a positive number represents the distance nasal to the pupil center (μm).</p

Values and locations of the minimum corneal thickness in the area 5 mm from the pupil center in 614 normal Chinese children.

<p>Values and locations of the minimum corneal thickness in the area 5 mm from the pupil center in 614 normal Chinese children.</p

Inclusion and exclusion flowchart for analyzing corneal thickness and associated factors.

<p>CT, corneal thickness; IOP, intraocular pressure.</p

Comparison of the time trade-off and rating scale utility values from patients and ophthalmologists.

<p>TTO, time trade-off; RS, rating scale; SD, standard deviation; CI, confidence interval.</p><p>* <i>p</i> value comparing the TTO and SG methods within each visual group using the paired two-tailed Student’s t test.</p><p>Comparison of the time trade-off and rating scale utility values from patients and ophthalmologists.</p

Demographic and clinical characteristics of 109 patients with diabetic retinopathy.

<p>DR, diabetic retinopathy; SD, standard deviation; CI, confidence interval; BCVA, best-corrected visual acuity; DM, diabetes mellitus; NPDR, non-proliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy; DME, diabetic macular edema.</p><p>Demographic and clinical characteristics of 109 patients with diabetic retinopathy.</p

Predictors of time trade-off and rating scale utility values from diabetic retinopathy patients and ophthalmologists, determined by bivariate analyses.

<p>DR, diabetic retinopathy; TTO, time trade-off; RS, rating scale; DME, diabetic macular edema.</p><p>*Pearson correlation coefficients and analysis of variance (ANOVA) were used.</p><p>Predictors of time trade-off and rating scale utility values from diabetic retinopathy patients and ophthalmologists, determined by bivariate analyses.</p

Scatter dot-plots of utility values from diabetic retinopathy patients and ophthalmologists, using the time trade-off method.

<p>Scatter dot-plots of utility values from diabetic retinopathy patients and ophthalmologists, using the time trade-off method.</p