Enhanced Uptake and Selectivity of CO₂ Adsorption in a Hydrostable Metal–Organic Frameworks via Incorporating Methylol and Methyl Groups

A new methylol and methyl functionalized metal–organic frameworks (MOFs) QI-Cu has been designed and synthesized. As a variant of NOTT-101, this material exhibits excellent CO₂ uptake capacities at ambient temperature and pressure, as well as high CH₄ uptake capacities. The CO₂ uptake for QI-Cu is high, up to 4.56 mmol g^–1 at 1 bar and 293 K, which is top-ranked among MOFs for CO₂ adsorption and significantly larger than the nonfunctionalized NOTT-101 of 3.93 mmol g^–1. The enhanced isosteric heat values of CO₂ and CH₄ adsorption were also obtained for this linker functionalized MOFs. From the single-component adsorption isotherms, multicomponent adsorption was predicted using the ideal adsorbed solution theory (IAST). QI-Cu shows an improvement in adsorptive selectivity of CO₂ over CH₄ and N₂ below 1 bar. The incorporation of methylol and methyl groups also greatly improves the hydrostability of the whole framework

Expressed abundance of some rhizome formation-related genes identified previously.

<p>TMP, transcripts per million clean tags.</p

Categorization and abundance of tags.

<p>About 5.0 million tags were sequenced, and clean tags and distinct tags were obtained after removal of low quality tags from each library. Some distinct tags were unambiguous tags after mapping to the reference genes, and some were unambiguous tag-mapped genes.</p

Validation of tag-mapped genes from three stages of lotus root with quantitative RT–PCR.

<p>Validation of tag-mapped genes from three stages of lotus root with quantitative RT–PCR.</p

Distribution of total clean tags and distinct clean tags count from the four libraries.

<p>Distribution of total clean tags and distinct clean tags count from the four libraries.</p

DEGs across all libraries.

<p>All the genes mapped to the reference sequence and genome sequences were examined for their expression differences across different libraries. Numbers of differentially expressed genes represent transcripts, using threshold values FDR≤0.001 and |log2 Ratio|≥1 for controlling false discovery rates. L1, L2, L3, and L4 represent the samples which were collected at stolon stage, initial swelling stage, middle swelling stage, and later swelling stage of rhizome, respectively.</p

Analysis of tag mapped genes among four libraries.

<p>Analysis of tag mapped genes among four libraries.</p

Expression abundance of up-regulated transcriptional factors during rhizome formation.

<p>Expression abundance of up-regulated transcriptional factors during rhizome formation.</p

Detailed information about primers used for qRT-PCR variation.

<p>All primers used for qPCR were designed according to CDS obtained in this study in lotus root.</p

20 most differentially expressed annotated genes in L1/L2, L2/L3, and L3/L4 libraries based on expressed tag frequency.

<p>20 most differentially expressed annotated genes in L1/L2, L2/L3, and L3/L4 libraries based on expressed tag frequency.</p