The adsorption behavior of the methyl blue dye molecule, a mutagenic agent onto the graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets, has been investigated at different pH values, adsorption times, temperatures, and also in the presence of different ions like Na+, Ca2+, Mg2+, and SO4 2–. A green solution chemistry approach has been adopted for the synthesis of rGO where ascorbic acid is used as a reducing agent under ultrasonication. A kinetic investigation has revealed that adsorption of methyl blue at the GO/rGO nanosheets–water interface follows linear pseudo second-order kinetics. The endothermic and spontaneous nature of the adsorption process was ascertained by the thermodynamic parameters such as Gibbs free energy change (ΔG°), enthalpy change (ΔH°), and entropy changes (ΔS°). The adsorption density of methyl blue at the GO nanosheet–water interface increases with increasing pH of the medium, while it decreases at the rGO nanosheet–water interface. Such results indicates that methyl blue interacts with GO nanosheets mainly by its positively charged (N+H) group, while with rGO nanosheets interact by its negatively charged SO3 – groups. The influence of presence of different monovalent and divalent ions like Na+, Ca2+, Mg2+, and SO4 2– on the adsorption density of the methyl blue onto the GO and rGO nanosheets was also investigated. The mechanism of the adsorption process was finally investigated by diffuse reflectance infrared Fourier transform (DRIFT) spectra of GO and rGO nanosheets before and after adsorption of methyl blue dye molecule.

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One neotype, three second-step lectotypes and fourty lectotypes are designated for fourty four names in Indian Impatiens to fix the identity and to avoid the misapplication of names. Thirty nine names are synonymized, after a detailed ecological study of live plants in the field and examination of herbarium specimens including types. Six new combinations with change in their status are proposed for six taxa.

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Graphene oxide (GO) is amphiphilic in nature, due to its structure, which consists of hydrophilic oxygen-containing functional groups and a hydrophobic basal plane of polyaromatic benzene rings. Due to this amphiphilicity, GO can create stable bubbles at water-organic solvent interfaces. In this study, the formation of bubbles at aqueous-organic interfaces in the presence of GO is investigated with different organic solvents. Bubble formation and transfer of GO from water to the organic phase is more prominent in aromatic solvents compared to aliphatic solvents, due to π-π interactions. Maximum transfer of GO from the aqueous to the organic phase is achieved at pH 2, and decreases with rising pH of the aqueous phase. Based on this property, and the ability of GO to adsorb cationic and anionic dye molecules, its application as a carrier for reactive extraction of cationic and anionic dye molecules is explored in toluene, kerosene, and carbon tetrachloride at pH 2 and 25 °C. The kinetics of the adsorption of the dyes onto GO nanosheets that takes place in the aqueous phase is also evaluated with different models, and a pseudo-second-order (linear) model is found to be the best fit. The adsorption isotherm data are also analyzed with different isotherm models. The electrostatic interaction and π-π interaction between the dye molecules and GO nanosheets leads to dye extraction of up to 98.2% using this technique. The dye extraction is maximum in toluene and at low dye concentration.

Henckelia collegii-sancti-thomasii, a new species of Henckelia is described here from Nirijuli, Papum Pare district of Arunachal Pradesh, northeastern India. Detailed description, its habitat and ecology along with color photographs are provided.

The genus Henckelia Spreng. (Gesneriaceae), in the sense of Weber et al. (2011), presently includes about 73 species, distributed from China and N India to S India and Sri Lanka and from W India to Vietnam. In India, it is represented by 37 species, of which 21 species occur in western, eastern Himalaya and northeast India, and 16 species in the Western Ghats.During the authors' work on the floristic diversity of the Eastern Himalayan state Arunachal Pradesh, India, specimens of two Henckelia species were collected in the Lower Subansiri and Kurung Kumey districts (Figure 1), that proved new on closer inspection. They are formally described here as new species. | MATERIAL AND METHODSSpecimens of the two new species of Henckelia were collected during plant collection trips to Arunachal Pradesh from 2017 to 2019. Type specimens were deposited at ARUN and ASSAM. For comparison, material was studied from ARUN, ASSAM, BM, CAL, E, G, K, L, MH, P and PE. The number of mature individuals found in the type locality was recorded for both species for assessment of the conservation status.