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Synergetic adsorption and photo-Fenton degradation of methylene blue by ZnFe <sub/>2</sub> O <sub/>4</sub> /SiO <sub/>2</sub> magnetic double-mesoporous-shelled hollow spheres
摘要： Adsorption and Fenton technologies have been widely employed to deal with wastewater. ZnFe2O4/SiO2 magnetic double-mesoporous-shelled hollow spheres (MDSHSs) were feasibly synthesized by a solvothermal method. The as-synthesized MDSHSs show excellent adsorption and selectivity for methylene blue (MB), which it took about only 1 min to reach the adsorption equilibrium. About 50% MB was removed by adsorption, and other 50% MB was degraded under further photo-Fenton process. Effects of experimental conditions on the adsorption and photo-Fenton process were investigated. The mechanisms of MDSHSs formation and photo-Fenton process were proposed. Total organic carbon (TOC) reduction reached as high as 90% with 60 mg/L of MB for 90 min. The experimental results indicated that MDSHSs exhibit a remarkable adsorption and catalytic activity for photo-Fenton process in a wide pH range of 3.3–11.0. Simultaneously, the composite shows an excellent stability and reusability.
关键词： photo-Fenton,magnetic property,porous materials,ZnFe2O4/SiO2,adsorption
更新于2025-09-23 15:19:57
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Filler-Modified Castor Oil-Based Polyurethane Foam for the Removal of Aqueous Heavy Metals Detected Using Laser-Induced Breakdown Spectroscopy (LIBS) Technique
摘要： The use of polymeric material in heavy metal removal from wastewater is trending. Heavy metal removal from wastewater of the industrial process is of utmost importance in green/sustainable manufacturing. Production of absorbent materials from a natural source for industrial wastewater has been on the increase. In this research, polyurethane foam (PUF), an adsorbent used by industries to adsorb heavy metal from wastewater, was prepared from a renewable source. Castor oil-based polyurethane foam (COPUF) was produced and modified for improved adsorption performance using fillers, analyzed with laser-induced breakdown spectroscopy (LIBS). The fillers (zeolite, bentonite, and activated carbon) were added to the COPUF matrix allowing the modification on its surface morphology and charge. The materials were characterized using Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and thermal gravimetry analysis (TGA), while their adsorption performance was studied by comparing the LIBS spectra. The bentonite-modified COPUF (B/COPUF) gave the highest value of the normalized Pb I (405.7 nm) line intensity (2.3), followed by zeolite-modified COPUF (Z/COPUF) (1.9), and activated carbon-modified COPUF (AC/COPUF) (0.2), which indicates the adsorption performance of Pb2+ on the respective materials. The heavy metal ions’ adsorption on the B/COPUF dominantly resulted from the electrostatic attraction. This study demonstrated the potential use of B/COPUF in adsorption and LIBS quantitative analysis of aqueous heavy metal ions.
关键词： LIBS,polyurethane,characterization,castor oil,adsorption
更新于2025-09-23 15:19:57
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Synergy of adsorption and photocatalysis on removal of high-concentration dye by Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O nanocomposite using Bi12O17Cl2 as bismuth source
摘要： Novel basic bismuth nitrite nanocomposite-Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O has been applied to remove high-concentration methyl orange (MO). The nanocomposite was prepared by a two-step method with Bi12O17Cl2 as bismuth source. XRD, TEM, HRTEM and IR analyses were performed to clarify the composition and microstructure. TEM and HRTEM images reveal that the nanocomposite is consisted of plate-stacking Bi6O4(OH)4(NO3)6·H2O ultrathin nanosheets, where monodispersed AgCl (3-7 nm) and Ag (10-120 nm) nanoparticles are uniformly distributed. Influences of contact time, MO concentration and solution pH on adsorption capacity have been studied. Adsorption capacity is 349 mg g-1 at natural state, 740 mg g-1 at pH=3, and 141 mg g-1 at pH=9. Visible-light photocatalytic performance was evaluated by degradating high-concentration MO of 500 mg L-1 at natural state, 1500 mg L-1 at acidic condition, and 300 mg L-1 at the alkaline condition. Combining with distinct composition and structure of the nanocomposite, removal mechanism is proposed based on the synergy of adsorption and photocatalysis.
关键词： Adsorption,Photocatalysis,Synergy,High-concentration methyl orange,Ag/AgCl/Bi6O4(OH)4(NO3)6·H2O
更新于2025-09-23 15:19:57
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SOLAR-POWERED ADSORPTION REFRIGERATION CYCLE OPTIMIZATION
摘要： Solar energy is an attractive energy source among various renewable energy resources in Malaysia as relatively high solar radiation is available throughout the year. This solar energy can be utilized for air-conditioning by using solar-powered adsorption refrigeration cycle. Intermittent nature of the solar radiation leads to a challenge for continuous air-conditioning operation. In the present study, a combination of solar-powered adsorption refrigeration system and thermal storage is studied. Activated carbon-ammonia and activated carbon-methanol are the working pairs of the adsorption reaction. Analytical calculation results show that activated carbon-methanol pair indicates higher coefficient of performance (COP) than activated carbon-ammonia pair, while adsorption chiller system with hot water thermal storage has higher COP than the system with ice thermal storage. For the activated carbon-methanol case with hot water thermal storage, the COP is 0.79. Since this COP analysis is based on the ideal case with uniform temperature distribution within the reactor beds, which achieves equilibrium states at the end of the reactions. In more realistic situation, the reaction process will be terminated before reaching to the equilibrium states because of the non-uniform temperature distribution and the time required for the reaction. Transient simulation in which heat transfer and reaction equation are combined will be performed to model actual reactors.
关键词： Solar-powered,thermal storage,adsorption capacity,adsorption refrigeration
更新于2025-09-19 17:15:36
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Exploring the surface chemistry of cesium lead halide perovskite nanocrystals
摘要： Colloidal nanocrystals (NCs) of cesium lead halide perovskites (CsPbX3, X = Cl, Br or I) are emerging as an exciting class of optoelectronic materials, but the retention of their colloidal and structural integrity during isolation, purification and handling still represents a critical issue. The impelling questions concerning their intrinsic chemical instability are connected to the dynamic nature of the bonding between the inorganic surface and the long-chain capping ligands. However, the key aspects of CsPbX3's surface chemistry that directly impact their stability remain elusive. In this contribution, we provide an in-depth investigation of the surface properties of differently composed CsPbX3 NCs, prepared by traditional hot-injection methods. The study, mainly relying on solution NMR spectroscopy, is backed up by elemental analysis as well as morphological, structural and optical investigations. We ascertained that the nature of the ligand adsorption/desorption processes at the NC surface is dependent on its elemental composition, thus explaining the origin of the instability afflicting CsPbI3 NCs. We also evaluated the effect of NC purification as well as of the degradation pathways involving the organic shell on the surface chemistry of CsPbX3 NCs. This study paves the way for new post-functionalization strategies for this promising class of nanomaterials.
关键词： surface chemistry,colloidal stability,degradation pathways,cesium lead halide perovskite nanocrystals,purification,ligand adsorption/desorption,NMR spectroscopy
更新于2025-09-19 17:15:36
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First-principles investigation on detection of phosgene gas molecules using phosphorene nanosheet device
摘要： Non-Equilibrium Green’s function (NEGF) and density functional theory (DFT) method is employed in exploring the geometric, electronic and adsorption aspects of phosgene (COCl2) on phosphorene nanosheet based molecular device. Further, the attributes such as Bader charge transfer, energy band gap, and average energy gap variation assists in scrutinizing the surface assimilating properties of COCl2 gas on phosphorene nanosheet. Besides, the detection properties of COCl2 gas molecules using the phosphorene nanosheet device are evidenced by the transmission spectrum and V-I characteristics. Thus, the current work establishes the foundation for employing phosphorene nanosheet based molecular device in sensing COCl2 gas molecules.
关键词： Nanosheet,Phosgene,Adsorption,Density of states,Phosphorene
更新于2025-09-19 17:15:36
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A multifunctional anionic 3D Cd(II)-MOF derived from 2D layers catenation: Organic dyes adsorption, cycloaddition of CO2 with epoxides and luminescence
摘要： An anionic Cd(II)-based metal-organic framework, {[Cd(L)(bpb)0.5(H2O)]·H2O·[(CH3)2NH2]+}n (HL-7, HL is the initial of the author Hui-Ling Liu; H3L = 2′,6′-dimethyl-[1,1′-biphenyl]-3,4′,5-tricarboxylic acid and bpb = 1,4-bis(pyrid-4-yl)benzene), has been hydrothermally synthesized and structurally characterized. Interestingly, HL-7 reveals a three dimensional (3D) frameworks which are constructed from catenation of 2D layers. Further studies prove that as an anionic framework, HL-7 could be a good candidate as adsorption materials for cationic organic dyes, such as methylene blue (MB+) and rhodamine B (RhB+). Moreover, catalytic properties for the cycloaddition of CO2 with epoxides and luminescent property of HL-7 are also investigated at normal temperature and pressure.
关键词： Catalysis,Dye adsorption,Luminescence,Metal-organic frameworks
更新于2025-09-19 17:15:36
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Green Waste-Derived Substances Immobilized on SBA-15 Silica: Surface Properties, Adsorbing and Photosensitizing Activities towards Organic and Inorganic Substrates
摘要： Urban wastes are a potential source of environment contamination, especially when they are not properly disposed. Nowadays, researchers are finding innovative solutions for recycling and reusing wastes in order to favour a sustainable development from the viewpoint of circular economy. In this context, the lignin-like fraction of biomass derived from Green Compost is a cost-effective source of soluble Bio-Based Substances (BBS-GC), namely complex macromolecules/supramolecular aggregates characterized by adsorbing and photosensitizing properties. In this work BBS-GC were immobilized on a silica support (SBA-15) and the chemico-physical properties of the resulting hybrid material (BBS-SBA) were analysed by zeta-potential measurements, nitrogen adsorption at 77K and micro-calorimetric techniques. Successively, the BBS-SBA photosensitizing and adsorption abilities were tested. Adsorption in the dark of Rhodamine B and Orange II on BBS-SBA and their degradation upon irradiation under simulated solar light were shown, together with the formation of hydroxyl radicals detected by Electron Paramagnetic Resonance spectroscopy. Furthermore, the adsorption of six inorganic ions (Al, Ni, Mn, As, Hg, Cr) on BBS-SBA was studied in pure water at two different pH values and in a landfill leachate, showing the good potential of this kind of materials in the removal of wastewater contaminants.
关键词： photocatalysis,wastewater treatment,orange,adsorption,waste-derived substances,hybrid silica,rhodamine
更新于2025-09-19 17:15:36
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Dependance of Poly(acrylic acid) Interfacial Adhesion on the Nanostructure of Electrodeposited ZnO Films
摘要： Understanding the impact of the intricate morphology and surface chemistry of ZnO nanorod arrays on their interactions with polyelectrolyte polymers is crucial for the development of nascent ZnO-based adhesion-promoting materials. AFM based Single Molecule Force Spectroscopy (SMFS) was applied for the analysis of the adsorption of poly(acrylic acid) (PAA) on zinc oxide (ZnO) film covered stainless steel substrates in aqueous electrolytes at pH 7. Based on the electrodeposition process, the morphology of zinc oxide films could be varied ranging from platelet-like crystals to nanorods. This approach allowed for the morphology dependent analysis of macromolecular adsorption processes on complex ZnO nanostructures which have diverse applications in the field of adhesion-promoting thin films. The surface chemical composition, as determined by X-ray photoelectron spectroscopy, could be correlated to the AFM-based desorption studies. Only equilibrium desorption events (plateaus), centered at 42 pN, were observed on mirror polished, preconditioned stainless steel. However, for platelet-like ZnO films, the poly(acrylic acid) desorption showed a mixture of rupture events (mean rupture forces of about 350 pN) and equilibrium desorption, while ZnO nanorod structures showed solely rupture events with mean rupture forces of about 1300 pN. These results indicate that simultaneous multiple ruptures of carboxylate-zinc bonds occur due to the macromolecular coordination of poly(acrylic acid) to the ZnO nanorods. The analysis of the interfacial adhesion processes is further supported by the dwell time dependence of desorption processes.
关键词： poly(acrylic acid),Single Molecule Force Spectroscopy (SMFS),worm like chain (WLC) model,stainless steel,zinc oxide (ZnO),electrochemical deposition,molecular adhesion,adsorption free energy
更新于2025-09-19 17:15:36
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Removal of Textile Dye from Aqueous Media Using an Advanced Oxidation Process with UV/H <sub/>2</sub> O <sub/>2</sub>
摘要： This study investigated the treatment of water contaminated with textile dye (Cibacron Red FN-R, reactive red 238) using a UV/H2O2 process. The reaction was influenced by the input concentration of hydrogen peroxide H2O2, pH, temperature, and the concentration of textile dye in the wastewater. Analysis of the experimental results displayed both first order and the second order reactions. The reaction type was found to be of a first order throughout the systems. The removal efficiency of the UV/ H2O2 process at optimal conditions and dosage (H2O2 = 25 mg/L, pH=3, temperature =20 ?C for 50 mg/L dye concentration) were found to be 80.633% , 97.07%, and 99.43% at 60 min, 120 min, and 180 min, respectively with K1 = 0.0293 min-1 and R2=0.9992%. COD removal was also studied for the UV/H2O2 process and found to be 62.5%.
关键词： Hydrogen peroxide,Ozonation process,Destruction of organic and inorganic contaminants,Advanced Oxidation Processes (AOPs),Fenton process,adsorption,coagulation
更新于2025-09-19 17:15:36