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Sirintornthep Towprayoon - One of the best experts on this subject based on the ideXlab platform.
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adsorption of three azo reactive dyes by Metal Hydroxide sludge effect of temperature ph and electrolytes
Journal of Colloid and Interface Science, 2004Co-Authors: Suchapa Netpradit, Paitip Thiravetyan, Sirintornthep TowprayoonAbstract:Abstract Adsorption of azo reactive dyes by Metal Hydroxide sludge were investigated using CI Reactive Red 2 (RR-2), CI Reactive Red 120, (RR-120), and CI Reactive Red 141 (RR-141). The adsorption isotherms, including the Langmuir constants (Q° and b) and the Freundlich constant (Kf), for RR-2 decreased with increasing temperature, but this was reversed for RR-120 and RR-141. This behavior implied an exothermic process for RR-2 but an endothermic process for RR-120 and RR-141. The enthalpy value of adsorption for RR-2, RR-120, and RR-141 was −5.56, 2.77, and 6.41 kJ/mol, respectively, indicating that the adsorption of the less charged dyes (RR-2) was mainly physical, but that of the more charged dyes (RR-120 and RR-141) was chemical. The optimum system pH of 8.6±0.3 was maintained even when the solution pH was varied from 3 to 10. Higher concentration or more valence of anions of electrolytes in dye solution caused decreasing dye adsorption efficiency of Metal Hydroxide sludge. A higher dosage of sludge is required for real textile wastewater (>1% w/v) than for the synthetic dye solution (0.2% w/v). The leachates of heavy Metals from Metal Hydroxide sludge to the environment are very low, which are within the standard limit of industrial effluent and leachable substances.
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application of waste Metal Hydroxide sludge for adsorption of azo reactive dyes
Water Research, 2003Co-Authors: Suchapa Netpradit, Paitip Thiravetyan, Sirintornthep TowprayoonAbstract:Abstract The capacity and mechanism of Metal Hydroxide sludge in removing azo reactive dyes from aqueous solution was investigated with different parameters, such as charge amount of dyes, system pH, adsorbent particle size, and adsorbent dosage. The three anionic dyes used were CI Reactive Red 2, CI Reactive Red 120, and CI Reactive Red 141, increasing in number of sulfonic groups, respectively. Only 0.2% (w/v) of powdered sludge ( −1 reactive dye solutions within 5 min without pH adjustment. The larger the charge amount of the dyes, the greater the adsorption (>90%) on the Metal Hydroxide sludge. The system pH played a significant role in the adsorption on Metal Hydroxides and formation of dye–Metal complexes. The optimum system pH for dye adsorption was 8–9 which was close to the pH zpc of the sludge while the precipitation of dye–Metal complexes occurred at system pH 2. The maximum adsorption capacity ( Q °) of the sludge for the reactive dyes was 48–62 mg dye g −1 adsorbent. The Langmuir and Freundlich models showed that the higher charged dyes had a higher affinity of adsorption. The smaller particle size and the greater amount of adsorbent showed the faster process, due to an increase in surface area of adsorbent. Desorption studies elucidated that Metal Hydroxide sludge had a tendency for ion exchange adsorption of sulfonated azo reactive dyes. Leaching data showed that the treated water was nontoxic at a system pH above 5 or a solution pH above 2.
Jin Hyeok Kim - One of the best experts on this subject based on the ideXlab platform.
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bifunctional 2d electrocatalysts of transition Metal Hydroxide nanosheet arrays for water splitting and urea electrolysis
ACS Sustainable Chemistry & Engineering, 2019Co-Authors: Pravin Babar, Vijay Karade, Myeng Gil Gang, A C Lokhande, B S Pawar, S M Pawar, Jin Hyeok KimAbstract:The replacement of noble-Metal-based electrocatalysts with earth-abundant, low-cost bifunctional electrocatalysts for efficient hydrogen generation is required. Herein, an amorphous and porous 2D N...
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Bifunctional 2D Electrocatalysts of Transition Metal Hydroxide Nanosheet Arrays for Water Splitting and Urea Electrolysis
2019Co-Authors: Pravi Aba, Abhishek Lokhande, Vijay Karade, Harati Pawa, Myeng Gil Gang, Sambhaji Pawa, Jin Hyeok KimAbstract:The replacement of noble-Metal-based electrocatalysts with earth-abundant, low-cost bifunctional electrocatalysts for efficient hydrogen generation is required. Herein, an amorphous and porous 2D NiFeCo Hydroxide nanosheets grown on nickel foam (NF) (NiFeCo LDH/NF) by a cost-effective electrodeposition method was explored for efficient electrolytic water splitting and urea electrolysis. Experimental results show that porous confinement in 2D orientation, amorphous nature, and synergistic effect leads to the excellent catalytical performance of the as-prepared 2D NiFeCo LDH/NF electrode for overall water splitting and urea electrolysis. The NiFeCo LDH/NF electrode presents promising behavior for water electrolysis with a small overpotential of 210 mV and 108 mV, respectively, is required for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) to gain 10 mA cm–2. More notably, the bifunctional NiFeCo LDH/NF catalyst, for water electrolysis, needs a lower potential of 1.57 V to gain 10 mA cm–2 in 1 KOH. Furthermore, the electrochemical urea oxidation results show that NiFeCo LDH/NF requires just 0.280 V (vs SCE) to drive 10 mA cm–2 in 1 M KOH with a 0.33 M urea, whereas urea-mediated electrolysis cells require a very low potential of 1.49 V at 10 mA cm–2. The present results provide remarkable and notable insights into the preparation of non-noble and highly efficient 2D transition Metal Hydroxide electrocatalysts with performances that allow them to compete for widespread use in various applications
Jihua Cai - One of the best experts on this subject based on the ideXlab platform.
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design and evaluation of a surfactant mixed Metal Hydroxide based drilling fluid for maintaining wellbore stability in coal measure strata
Energies, 2019Co-Authors: Shuya Chen, Yanping Shi, Xianyu Yang, Kunzhi Xie, Jihua CaiAbstract:Co-exploitation of coal measure gases (coalbed gas, shale gas, and tight sandstone gas) puts a higher requirement on drilling fluids. Conventional drilling fluids have disadvantages, such as causing problems of borehole collapse, formation damage, and water blockage. This paper proposes a set of high inhibitive and low-damage drilling fluids that function by electrical inhibition and neutral wetting. Zeta potential results showed that the negative electrical property of Longtan coal in Bijie, Guizhou, can be reversed by organic mixed Metal Hydroxide (MMH) and the cationic surfactant alkyl trimethylammonium bromide (CS-5) from −3.63 mV to 19.75 mV and 47.25 mV, respectively. Based on the contact angle and Fourier Transform Infrared Spectroscopy (FT-IR) results, it can be concluded that chemical adsorption dominates between the Longmaxi shale and surfactants, and physical adsorption between the Longtan coal and surfactants. A compound surfactant formula (0.001 wt% CS-4 + 0.001 wt% CS-1 + 0.001 wt% CS-3), which could balance the wettability of the Longmaxi shale and the Longtan coal, making them both appear weakly hydrophilic simultaneously, was optimized. After being treated by the compound surfactants, the contact angles of the Longmaxi shale and the Longtan coal were 89° and 86°, respectively. Pressure transmission tests showed that the optimized combination of compound surfactants and inorganic MMH (MMH-1) could effectively reduce permeability of the Longmaxi shale and the Longtan coal, thus retarding pore pressure transmission in coal measure strata. Then, the proposed water-based drilling fluid (WBDF) system (4 wt% sodium bentonite + 1.5 wt% sodium carboxymethyl cellulose + 2 wt% lignite resin + 5 wt% potassium chloride + 3 wt%MMH-1 + 0.001 wt% CS-4 + 0.001 wt% CS-1 + 0.001 wt% CS-3) was evaluated based on parameters including rheology, American Petroleum Institute (API) filtration, electrical property, wettability, inhibition capability, reservoir protection characteristics, and anti-pollution performance. It had an API filtration of 7 mL, reservoir damage rate of 10%, moderate and acceptable viscosity, strong inhibition capability to coal measure strata rocks, good tolerance to inorganic pollutants and drilling cuttings, and environmentally friendly properties. It could meet wellbore stability and reservoir protection requirements in the co-exploitation of coal measure gases.
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Design and Evaluation of a Surfactant–Mixed Metal Hydroxide-Based Drilling Fluid for Maintaining Wellbore Stability in Coal Measure Strata
MDPI AG, 2019Co-Authors: Shuya Chen, Yanping Shi, Xianyu Yang, Kunzhi Xie, Jihua CaiAbstract:Co-exploitation of coal measure gases (coalbed gas, shale gas, and tight sandstone gas) puts a higher requirement on drilling fluids. Conventional drilling fluids have disadvantages, such as causing problems of borehole collapse, formation damage, and water blockage. This paper proposes a set of high inhibitive and low-damage drilling fluids that function by electrical inhibition and neutral wetting. Zeta potential results showed that the negative electrical property of Longtan coal in Bijie, Guizhou, can be reversed by organic mixed Metal Hydroxide (MMH) and the cationic surfactant alkyl trimethylammonium bromide (CS-5) from −3.63 mV to 19.75 mV and 47.25 mV, respectively. Based on the contact angle and Fourier Transform Infrared Spectroscopy (FT-IR) results, it can be concluded that chemical adsorption dominates between the Longmaxi shale and surfactants, and physical adsorption between the Longtan coal and surfactants. A compound surfactant formula (0.001 wt% CS-4 + 0.001 wt% CS-1 + 0.001 wt% CS-3), which could balance the wettability of the Longmaxi shale and the Longtan coal, making them both appear weakly hydrophilic simultaneously, was optimized. After being treated by the compound surfactants, the contact angles of the Longmaxi shale and the Longtan coal were 89° and 86°, respectively. Pressure transmission tests showed that the optimized combination of compound surfactants and inorganic MMH (MMH-1) could effectively reduce permeability of the Longmaxi shale and the Longtan coal, thus retarding pore pressure transmission in coal measure strata. Then, the proposed water-based drilling fluid (WBDF) system (4 wt% sodium bentonite + 1.5 wt% sodium carboxymethyl cellulose + 2 wt% lignite resin + 5 wt% potassium chloride + 3 wt%MMH-1 + 0.001 wt% CS-4 + 0.001 wt% CS-1 + 0.001 wt% CS-3) was evaluated based on parameters including rheology, American Petroleum Institute (API) filtration, electrical property, wettability, inhibition capability, reservoir protection characteristics, and anti-pollution performance. It had an API filtration of 7 mL, reservoir damage rate of 10%, moderate and acceptable viscosity, strong inhibition capability to coal measure strata rocks, good tolerance to inorganic pollutants and drilling cuttings, and environmentally friendly properties. It could meet wellbore stability and reservoir protection requirements in the co-exploitation of coal measure gases
Suchapa Netpradit - One of the best experts on this subject based on the ideXlab platform.
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adsorption of three azo reactive dyes by Metal Hydroxide sludge effect of temperature ph and electrolytes
Journal of Colloid and Interface Science, 2004Co-Authors: Suchapa Netpradit, Paitip Thiravetyan, Sirintornthep TowprayoonAbstract:Abstract Adsorption of azo reactive dyes by Metal Hydroxide sludge were investigated using CI Reactive Red 2 (RR-2), CI Reactive Red 120, (RR-120), and CI Reactive Red 141 (RR-141). The adsorption isotherms, including the Langmuir constants (Q° and b) and the Freundlich constant (Kf), for RR-2 decreased with increasing temperature, but this was reversed for RR-120 and RR-141. This behavior implied an exothermic process for RR-2 but an endothermic process for RR-120 and RR-141. The enthalpy value of adsorption for RR-2, RR-120, and RR-141 was −5.56, 2.77, and 6.41 kJ/mol, respectively, indicating that the adsorption of the less charged dyes (RR-2) was mainly physical, but that of the more charged dyes (RR-120 and RR-141) was chemical. The optimum system pH of 8.6±0.3 was maintained even when the solution pH was varied from 3 to 10. Higher concentration or more valence of anions of electrolytes in dye solution caused decreasing dye adsorption efficiency of Metal Hydroxide sludge. A higher dosage of sludge is required for real textile wastewater (>1% w/v) than for the synthetic dye solution (0.2% w/v). The leachates of heavy Metals from Metal Hydroxide sludge to the environment are very low, which are within the standard limit of industrial effluent and leachable substances.
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application of waste Metal Hydroxide sludge for adsorption of azo reactive dyes
Water Research, 2003Co-Authors: Suchapa Netpradit, Paitip Thiravetyan, Sirintornthep TowprayoonAbstract:Abstract The capacity and mechanism of Metal Hydroxide sludge in removing azo reactive dyes from aqueous solution was investigated with different parameters, such as charge amount of dyes, system pH, adsorbent particle size, and adsorbent dosage. The three anionic dyes used were CI Reactive Red 2, CI Reactive Red 120, and CI Reactive Red 141, increasing in number of sulfonic groups, respectively. Only 0.2% (w/v) of powdered sludge ( −1 reactive dye solutions within 5 min without pH adjustment. The larger the charge amount of the dyes, the greater the adsorption (>90%) on the Metal Hydroxide sludge. The system pH played a significant role in the adsorption on Metal Hydroxides and formation of dye–Metal complexes. The optimum system pH for dye adsorption was 8–9 which was close to the pH zpc of the sludge while the precipitation of dye–Metal complexes occurred at system pH 2. The maximum adsorption capacity ( Q °) of the sludge for the reactive dyes was 48–62 mg dye g −1 adsorbent. The Langmuir and Freundlich models showed that the higher charged dyes had a higher affinity of adsorption. The smaller particle size and the greater amount of adsorbent showed the faster process, due to an increase in surface area of adsorbent. Desorption studies elucidated that Metal Hydroxide sludge had a tendency for ion exchange adsorption of sulfonated azo reactive dyes. Leaching data showed that the treated water was nontoxic at a system pH above 5 or a solution pH above 2.
Vishnu P Kamath - One of the best experts on this subject based on the ideXlab platform.
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hydration induced interpolytype transformations in the bayerite derived nitrate intercalated layered double Hydroxide of li and al
Journal of Solid State Chemistry, 2018Co-Authors: Supreeth Nagendran, Ganga Periyasamy, Vishnu P KamathAbstract:Abstract The bayerite-derived layered double Hydroxide of Li and Al crystallizes in a hexagonal structure (space group P 3 ¯ 1 m ) on temperature induced dehydration. The Metal Hydroxide layers are stacked one above another [stacking vector (0, 0, 1)] in this crystal and the nitrate ion is intercalated with its molecular plane parallel to the Metal Hydroxide layer. On hydration, (i) there is an expansion in the basal spacing, and (ii) a translation of successive Metal Hydroxide layers by (1/3, 0, 1) relative to one another. Additionally numerous weak reflections emerge in the powder X-ray diffraction pattern possibly signifying a massive change in the packing of atoms in the interlayer. Partial structure refinement using only the major Bragg reflections suggests that the crystal adopts a structure of monoclinic symmetry (space group C2/m) with the nitrate ion oriented with its molecular plane perpendicular to the Metal Hydroxide layer. The complete pattern could be indexed to a cell of orthorhombic symmetry (space group P222) but the structure could not be refined for want of a structure model. The absence of a rational relationship between the cell parameters of the orthorhombic and monoclinic cells suggests that the hydrated phase crystallizes in either an incommensurate structure or in an entirely different crystal structure.
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Reappraisal of Polytypism in Layered Double Hydroxides: Consequences of Cation Ordering in the Metal Hydroxide Layer
2017Co-Authors: Latha Pachayappan, Supreeth Nagendran, Vishnu P KamathAbstract:Recent diffraction studies on layered double Hydroxides have shown that the three-layer polytypes that were thought to crystallize in rhombohedral symmetry are actually one-layer polytypes of monoclinic symmetry. However, the prevailing Bookin and Drits (1993) scheme of polytypism, which is based on the widely accepted cation-disordered structure model, fails to predict the occurrence of low symmetry (monoclinic and orthorhombic) polytypes among the layered double Hydroxides. In this work, a cation-ordered Metal Hydroxide layer (layer group p3̅12/m or c12/m1) is chosen as the basic building block. Application of the structural synthon approach enables the description of the complete universe of polytypes comprising 1H, 1M1–7, 2H, 2O, 3R, 3H, 6H, and 6R among others (M: monoclinic; O: orthorhombic). These polytypes are characterized by their unique stacking vectors. The polytypes of large unit cell volume are obtained by a combination of two or more stacking vectors. This work has relevance to the understanding of several mineral structures, especially those with large unit cells
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structure of the chloride and bromide intercalated layered double Hydroxides of li and al interplay of coulombic and hydrogen bonding interactions in the interlayer gallery
European Journal of Inorganic Chemistry, 2013Co-Authors: Supreeth Nagendran, Vishnu P KamathAbstract:Rietveld refinement of the structures of the [LixAl(OH)3]Xx·yH2O (X = Br, Cl; y ≈ 1/2, 2/3) layered double Hydroxides (LDHs) shows that the halide ion occupies two distinct positions in each phase. One position (2a), promoted by Coulombic attraction, is proximal to the Li+ ion, which is the seat of the positive charge in the Metal Hydroxide layer. The other position (6h) is within a close hydrogen-bonding distance from the hydroxy group of the Metal Hydroxide layer as well as the intercalated water molecule. The LDH with intercalated Br– ions crystallizes in two different structures, one of which is isostructural with the Cl– analogue. In the other structure obtained at a higher relative humidity (≥76 %; y ≈ 2/3), the Br– ion occupies a site proximal to the Al3+ ion (2b), and intercalated water molecules are proximal to the Li+ ion. In this structure, the hydration of the Li+ ion in a distant coordination shell overcomes Coulombic interactions with Br– ions. On partial dehydration (ambient humidity 29 %; y ≈ 1/2), this Br– ion reversibly reverts back to the site (2a) proximal to the Li+ ion, which results in a humidity-induced structure change without any variation in the basal spacing. Thereby, the position of the halide ion in the interlayer gallery is determined by the interplay of Coulombic and hydrogen-bonding interactions.
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structure of bayerite based lithium aluminum layered double Hydroxides ldhs observation of monoclinic symmetry
Inorganic Chemistry, 2009Co-Authors: Sylvia Britto, Vishnu P KamathAbstract:The double Hydroxides of Li with Al, obtained by the imbibition of Li salts into bayerite and gibbsite−Al(OH)3, are not different polytypes of the same symmetry but actually crystallize in two different symmetries. The bayerite-derived double Hydroxides crystallize with monoclinic symmetry, while the gibbsite-derived Hydroxides crystallize with hexagonal symmetry. Successive Metal Hydroxide layers in the bayerite-derived LDHs are translated by the vector (∼−1/3, 0, 1) with respect to each other. The exigency of hydrogen bonding drives the intercalated Cl− ion to a site with 2-fold coordination, whereas the intercalated water occupies a site with 6-fold coordination having a pseudotrigonal prismatic symmetry. The nonideal nature of the interlayer sites has implications for the observed selectivity of Li−Al LDHs toward anions of different symmetries.