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Tetrahydrofuran (THF) and dimethylsulfoxide (DMSO) are miscible in water due to hydrogen (H) bonding. Amphiphilic glycerol and sucrose esters with a different number of tails and heads separate them, depending on the organic solvent concentration. Separation is worse in solutions where amphiphiles are most soluble. Separation occurs due to interactions between the amphiphiles and either organic solvents or water, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Separation is best with glycerol esters with more heads and tails. Multiple tails hamper interactions between glycerol ester heads, thereby facilitating interactions with organic solvents or water to promote solvent–water separation. THF interacts with the glycerol ester tails, while water H bonds with the glycerol ester heads, as indicated by activity coefficients estimated with conductor-like screening model for real solvents. In THF, amphiphiles self-assemble into micelles, as shown by small angle x ray scattering (SAXS). Without water, THF is likely both inside and outside the micelles. SAXS shows that micelles shrink with 4% water in THF because water molecules partition inside them and are smaller than THF. With additional water, micelles swell into emulsions. Dissimilar to THF, DMSO preferentially interacts with the glycerol ester heads rather than their tails. ATR-FTIR shows that the proportion of free vs bonded S=O groups of DMSO decreases upon mixing with glycerol esters. DMSO and glycerol esters primarily accept H bonds, as indicated by their sigma profile. This leads to competition for interactions with water, displacing DMSO. [ABSTRACT FROM AUTHOR]

Hydrochar (HC) was obtained through the hydrothermal digestion of beetroot, carrot, or spent coffee grounds. The yield (i.e., mass of HC produced per mass of feedstock used) was [approximately equal to]80%, [approximately equal to]20%, and [approximately equal to]50% with spent coffee, carrot, and beetroot, respectively. The surface area determined with the Brunauer-Emmett-Teller method was 3.06 [m.sup.2] * [g.sup.-1] for HC from beetroot, 1.19 [m.sup.2] * [g.sup.-1] for HC from carrot, 2.84 [m.sup.2] * [g.sup.-1] for HC from dark roast coffee, and 3.22 [m.sup.2] * [g.sup.-1] for HC from original roast coffee. Fourier transform infrared spectroscopy experiments showed that amine groups had a significantly higher density in HC produced with spent coffee grounds than that produced using either beetroot or carrot. HC could sorb hexavalent chromium (Cr(VI)) from water. The concentration of Cr(VI) in water decreased from 0.3 ppm to [approximately equal to]0.07 ppm and to [approximately equal to]0.1 ppm within 90 min using 20 g * [L.sup.-1] of HC made from spent coffee grounds and from beetroot and carrot, respectively. Key words: hydrochar, sorption, hexavalent chromium (Cr(VI)), water treatment. L'hydrochar (HC) a ete produit par digestion hydrothermale de betteraves, de carottes ou de grains de cafe uses. Le rendement (c.-a-d. la masse d'HC produite par poids de matiere premiere utilisee) etait de [approximately equal to]80, [approximately equal to]20 et [approximately equal to]50 % avec le cafe use, la carotte et la betterave, respectivement. La superficie determinee selon la methode Brunauer-Emmett-Teller etait de 3,06 [m.sup.2] * [g.sup.-1] pour l'HC obtenu a partir de betteraves, de 1,19 [m.sup.2]-g_1 pour l'HC a partir de carottes, de 2,84 [m.sup.2] * [g.sup.-1] pour l'HC a partir de cafe torrefie fonce et de 3,22 [m.sup.2] * [g.sup.-1] pour l'HC a partir de cafe torrefie original. Les experiences de spectroscopie infrarouge a transformee de Fourier ont montre que les groupes d'amines avaient une densite significativement plus elevee dans l'HC produit avec des grains de cafe uses que dans l'HC produit avec de la betterave ou de la carotte. L'HC pouvait sorber le chrome hexavalent (Cr(VI)) present dans l'eau. La concentration de Cr(VI) dans l'eau a diminue de 0,3 ppm a 0,07 ppm et a 0,1 ppm en 90 min, en utilisant 20 g * [L.sup.-1] d'HC a base de grains de cafe uses et de betterave et de carotte, respectivement. [Traduit par la Redaction] Mots-cles: hydrochar, sorption, chrome hexavalent (Cr(VI)), traitement de l'eau., 1. Introduction Hexavalent chromium (Cr(VI)) is highly toxic. If inhaled, Cr(VI) can cause acute toxic effects, including ulceration of the nasal septum and asthma. If ingested, Cr(VI) may adversely affect [...]

This study shows that salt type and pH affect the removal of perfluorooctanoic acid (PFOA) from water through flocculation and electro-enhanced flocculation. PFOA concentrations decreased by approximately 80% with 20 mM Fe[Cl.sub.3] and initial pH = 3-10. Electro-enhanced flocculation at pH = 3 reduced PFOA concentrations in water by approximately 70% with Ca[Cl.sub.2] and KCl, and by 50% with NaCl. At alkaline pH, PFOA removal was approximately 20% with Ca[Cl.sub.2] and KCl. PFOA removal was negligible without salts or with Al[Cl.sub.3], and with NaCl at alkaline pH. Differences in PFOA removal are likely due to the settling behaviour of the cation-PFOA complexes formed. Key words: electro-enhanced flocculation, flocculation, interfacial tension, perfluorooctanoic acid, separation. Cette etude montre que le type de sel et le pH influent sur l'elimination de l'acide perfluorooctanoique (APFO) de l'eau par floculation et floculation electro-intensifiee. Les concentrations d'APFO ont diminue d'environ 80 % avec 20 mmol de Fe[Cl.sub.3] et un pH initial de 3-10. La floculation electro-intensifiee a pH = 3 a reduit les concentrations d'APFO dans l'eau d'environ 70 % avec le Ca[Cl.sub.2] et le KCl et de 50 % avec le NaCl. A un pH alcalin, l'elimination de l'APFO etait d'environ 20 % avec Ca[Cl.sub.2] et KCl. L'elimination de l'APFO etait negligeable sans sels ou avec l'Al[Cl.sub.3], et avec le NaCl a pH alcalin. Les differences dans l'elimination de l'APFO sont probablement attribuables au comportement de decantation des complexes cations-APFO formes. [Traduit par la Redaction] Mots-cles: floculation electro-intensifiee, floculation, tension interfaciale, acide perfluorooctanoique, separation., 1. Introduction Perfluorooctanoic acid (PFOA; Fig. 1) is a carcinogenic perfluorinated amphiphilic carboxylic acid and it is extremely persistent in the environment. PFOA has been detected in the blood of [...]

A calcium-rich rock (limestone) was used as adsorbent to remove phosphorus from water. Phosphorus could be subsequently desorbed from limestone at pH = 4, and potentially reused as fertilizer following pH neutralization. Sorption of phosphorus onto limestone was not affected by 100 mM KCl or by the nitrogen present in a commercial fertilizer, but it was hindered by 100 mM NaCl, urea and river water. The phosphorus removed was however never below ~9 mg P/kg rock, and it increased with increasing phosphorus concentrations in water. Phosphorus removal increased with 100 mM CaCl2 at neutral pH, likely due to its precipitation. Mixing for 30 s enhanced phosphorus sorption. Desorption of phosphorus from limestone following sorption in deionized water was ~50%, ~22%, and ~11% at pH = 4, pH = 7, and pH = 11, respectively. Phosphorus desorption was lower when sorption had occurred in river water than in deionized water or in 100 mM urea. Key words: phosphorus, agricultural, sorbent, calcium, rock, limestone. Une roche riche en calcium (calcaire) a ete utilisee comme adsorbant pour eliminer le phosphore de l'eau. Le phosphore pourrait subsequemment etre desorbe a partir du calcaire a un pH = 4 et potentiellement reutilise comme engrais apres la neutralisation du pH. La sorption du phosphore sur le calcaire n'a pas ete modifiee par 100 mM de KCl ni par l'azote present dans un engrais commercial, mais la sorption a ete freinee par 100 mM de NaCl, d'uree et d'eau de riviere. Le phosphore elimine n'a toutefois jamais ete inferieur a ~9 mg P/kg de roche, et il a augmente avec l'augmentation des concentrations de phosphore dans l'eau. L'elimination du phosphore a augmente avec 100 mM de CaCl2 a un pH neutre, probablement en raison de sa precipitation. En melangeant pendant 30 s, ilyaeu amelioration de la sorption du phosphore. La desorption du phosphore a partir du calcaire apres la sorption dans l'eau desionisee etait de ~50, ~22 et ~11 % a un pH = 4, pH = 7 et pH = 11, respectivement. La desorption du phosphore etait plus faible lorsque la sorption s'etait produite dans l'eau de riviere que dans l'eau desionisee ou dans 100 mM d'uree. [Traduit par la Redaction] Mots-cles: phosphore, agricole, sorbant, calcium, roche, calcaire., Introduction The ingress of phosphorus from overland into lakes causes eutrophication and algal blooms (Meinikmann et al. 2015; Schindler et al. 2016) and has become a significant issue in recent [...]