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With growing concerns over water pollution and depletion of freshwater resources, finding sustainable and cost-effective solutions for water treatment is crucial. This study introduces a novel MIL-53(Fe)/Mn-doped SrTiO 3 (MIL-53(Fe)/Mn-STO) direct Z-scheme photocatalyst, designed to efficiently degrade organic contaminants in water. Specifically, the photocatalytic degradation of o-nitrophenol (ONP) was investigated under an Xe lamp. The MIL-53(Fe)/Mn-STO photocatalyst demonstrated a maximum removal efficiency of 97.75% within 90 min, with a rate constant ( k ) of 0.0374 min −1 , outperforming the individual MIL-53(Fe) and Mn-STO photocatalysts. A comprehensive analysis of the material’s properties was conducted using Fourier transform Infrared spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence techniques, and the photocatalytic activity was evaluated under various conditions, including variations in pH, ONP concentration, catalyst dosage and the presence of inorganic anions. The improved photocatalytic activity of the MIL-53(Fe)/Mn-STO system can be ascribed to the synergistic interaction between its two components, which also contributed to its excellent recyclability over five cycles. These findings demonstrate that MIL-53(Fe)/Mn-STO is a highly effective and sustainable photocatalyst with a strong potential for wastewater treatment applications.

Water pollution is a dreadful affair that has incessantly aggravated, exposing our planet to danger. In particular, the persistent nitro aromatic compound like nitrophenols causes anxiety to the researchers due to their hazardous impacts, excessive usage, and removal difficulty. For this purpose, a novel multi-featured composite was constructed based on κ-Carrageenan (κ-Carr), MOF (MIL-125(Ti)), and magnetic Fe 3 O 4 for efficient adsorptive removal of o-nitrophenol (o-NP). Interestingly, BET measurements revealed the high surface area of Fe 3 O 4 -κ-Carr/MIL-125(Ti) of about 163.27 m 2 /g, while VSM showed its excellent magnetic property (20.34 emu/g). The comparison study pointed out the synergistic effect between Fe 3 O 4 , κ-Carr, and MIL-125(Ti), forming a composite with an excellent adsorption performance toward o-NP. The adsorption data obeyed pseudo-second-order kinetic model, and Freundlich isotherm model was better fitted than Langmuir and Temkin. Furthermore, Langmuir verified the supreme adsorption capacity of o-NP onto Fe 3 O 4 -κ-Carr/MIL-125(Ti) since the computed q max  reached 320.26 mg/g at pH 6 and 25 °C. Furthermore, the XPS results postulated that the adsorption mechanism pf o-NP proceeded via H-bonding, π - π interaction, and electron donor–acceptor interactions. Interestingly, Fe 3 O 4 -κ-Carr/MIL-125(Ti) composite retained good adsorption characteristics after reusing for five cycles, suggesting its viable applicability as an efficient, renewable, and easy-separable adsorbent for removing nitro aromatic pollutants.

This study reports a sustainable route for the synthesis of an eco-friendly adsorbent derived from Balanites aegyptiaca (Laloub) decorated with strontium oxide nanoparticles (SrO NPs) for the removal of ortho-nitrophenol (o-NP) from water. The plant extract was used as a reducing agent for the green synthesis of SrO-NPs, while the plant branches were used to prepare biomass (BM) and biochar (BC). The obtained composites (SrO-BM and SrO-BC) were characterized by XRD, FTIR, and SEM, that revealed that SrO NPs crystallinity, and confirmed the presence of functional oxygenated groups, with a uniform distribution of SrO-NPs on the BM and BC surfaces. A comparative study has been executed to evaluate whether converting BM into BC enhances its adsorption performance or represents wasted energy. The experimental results reflected that SrO-BC exhibited higher adsorption capacity of 335.57 mg/g toward o-NP compared with 234.74 mg/g for SrO-BM at optimum conditions of pH 5, 25 °C, and 0.5 g/L dosage. Adsorption isotherm models showed that the adsorption onto SrO-BM followed the Langmuir model, while that for SrO-BC followed Freundlich model with a pseudo-second-order behavior for both. Mechanistic insights suggested electron donor–acceptor interactions, hydrogen bonding, π–π stacking, and coordination bonding as governing pathways. Reusability tests confirmed adsorbent stability since they retained more than 80% of their removal efficiency after five cycles. These findings provide a green and eco-friendly route to fabricate efficient and reusable adsorbents derived from Balanites aegyptiaca with a superior adsorption potential of SrO-BC for sustainable wastewater treatment.

Worldwide industrialization has grown at a rapid pace, contaminating water resources, particularly with phenolic pollutants that pose a risk to aquatic systems and human health. The goal of this study is to create an inexpensive magnetic composite that can effectively remove nitrophenol (o-NP) using adsorptive means. In this instance, a nonanyl chitosan (N-Cs) derivative was synthesized and then combined with activated petroleum coke (AP-coke) and magnetic Fe 3 O 4 to boost its adsorbability towards o-NP and to facilitate its separation. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffractometer (XRD), Vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and zeta potential were employed to characterize the magnetic composite. The experimental results indicated that the Fe 3 O 4 /AP-coke/N-Cs composite possesses a greater affinity toward o-NP with a maximal efficiency reached 88% compared to 22.8, 31.2, and 45.8% for Fe 3 O 4 , AP-coke and N-Cs, respectively. The equilibrium adsorption data coincided with the Langmuir, Freundlich, and Temkin isotherm models, with a maximum adsorption capacity of 291.55 mg/g at pH 6, whereas the pseudo second order kinetic model offered the best fit to the experimental data. Besides, the developed adsorbent preserved satisfactory adsorption characteristics after reuse for five successive cycles. The proposed adsorption mechanism involves the H-bonding, π-π interaction, hydrophobic interactions and electron donor-acceptor interactions. These findings hypothesize that the constructed magnetic composite could efficiently remove nitrophenols from polluted water with high performance and ease-separation.

With growing concerns over water pollution and depletion of freshwater resources, finding sustainable and cost-effective solutions for water treatment is crucial. This study introduces a novel MIL-53(Fe)/Mn-doped SrTiO3 (MIL-53(Fe)/Mn-STO) direct Z-scheme photocatalyst, designed to efficiently degrade organic contaminants in water. Specifically, the photocatalytic degradation of o-nitrophenol (ONP) was investigated under an Xe lamp. The MIL-53(Fe)/Mn-STO photocatalyst demonstrated a maximum removal efficiency of 97.75% within 90 min, with a rate constant (k) of 0.0374 min-1, outperforming the individual MIL-53(Fe) and Mn-STO photocatalysts. A comprehensive analysis of the material's properties was conducted using Fourier transform Infrared spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence techniques, and the photocatalytic activity was evaluated under various conditions, including variations in pH, ONP concentration, catalyst dosage and the presence of inorganic anions. The improved photocatalytic activity of the MIL-53(Fe)/Mn-STO system can be ascribed to the synergistic interaction between its two components, which also contributed to its excellent recyclability over five cycles. These findings demonstrate that MIL-53(Fe)/Mn-STO is a highly effective and sustainable photocatalyst with a strong potential for wastewater treatment applications.With growing concerns over water pollution and depletion of freshwater resources, finding sustainable and cost-effective solutions for water treatment is crucial. This study introduces a novel MIL-53(Fe)/Mn-doped SrTiO3 (MIL-53(Fe)/Mn-STO) direct Z-scheme photocatalyst, designed to efficiently degrade organic contaminants in water. Specifically, the photocatalytic degradation of o-nitrophenol (ONP) was investigated under an Xe lamp. The MIL-53(Fe)/Mn-STO photocatalyst demonstrated a maximum removal efficiency of 97.75% within 90 min, with a rate constant (k) of 0.0374 min-1, outperforming the individual MIL-53(Fe) and Mn-STO photocatalysts. A comprehensive analysis of the material's properties was conducted using Fourier transform Infrared spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence techniques, and the photocatalytic activity was evaluated under various conditions, including variations in pH, ONP concentration, catalyst dosage and the presence of inorganic anions. The improved photocatalytic activity of the MIL-53(Fe)/Mn-STO system can be ascribed to the synergistic interaction between its two components, which also contributed to its excellent recyclability over five cycles. These findings demonstrate that MIL-53(Fe)/Mn-STO is a highly effective and sustainable photocatalyst with a strong potential for wastewater treatment applications.

The 6SA-CASSCF(10, 10)/6-31G (d, p) quantum chemistry method has been applied to perform on-the-fly trajectory surface hopping simulation with global switching algorithm and to explore excited-state intramolecular proton transfer reactions for the o-nitrophenol molecule within low-lying electronic singlet states (S 0 and S 1 ) and triplet states (T 1 and T 2 ). The decisive photoisomerization mechanisms of o -nitrophenol upon S 1 excitation are found by three intersystem crossings and one conical intersection between two triplet states, in which T 1 state plays an essential role. The present simulation shows branch ratios and timescales of three key processes via T 1 state, non-hydrogen transfer with ratio 48% and timescale 300 fs, the tunneling hydrogen transfer with ratios 36% and timescale 10 ps, and the direct hydrogen transfer with ratios 13% and timescale 40 fs. The present simulated timescales might be close to low limit of the recent experiment results.

A ternary photocatalyst composite-Silver decorated on ZnO supported with activated carbon (Ag/ZnO-AC) was investigated for the synthesis, characterization and UV assisted photocatalytic degradation of phenols and dyes present in wastewater. XPS and TEM revealed the elemental composition and formation of ternary Ag/ZnO-AC composite. Different operational parameters including the effect of calcination temperature, catalyst dose, initial concentration of pollutant and the effect of H2O2 and ethanol were studied. The photocatalytic activity was assessed for the degradation of p-Nitrophenol (PNP), o-Nitrophenol (ONP), and dye methyl orange (MO) under UV irradiation by ZnO, Ag/ZnO and Ag/ZnO-AC catalyst. The degradation for PNP, ONP and MO in presence of UV light were found to be in the order Ag/ZnO-AC>Ag/ZnO>ZnO. Improved degradation by Ag/ZnO-AC is attributed to high charge separation and greater adsorption of pollutant because of the combination of Ag and AC leading to a synergistic effect in the catalyst. Along with the high reusability, the composite catalyst Ag/ZnO-AC was found to be non-selective and cost-effective for the degradation of phenols as well as dyes. The as synthesized ternary composite Ag/ZnO-AC can be efficiently used as a photocatalyst for the degradation of recalcitrant and other deleterious contaminants present in wastewater.

Two kinds of fluorescent conjugated microporous polymers containing pyrazine moieties were prepared by the polymerization reaction of 2,5-di-triphenylamine-yl-pyrazine (DTPAPz) and N,N,N′,N′-tetrapheny-2,5-(diazyl) pyrazine (TDPz) with 2,4,6-trichloro-1,3,5-triazine (TCT) through Friedel–Crafts reaction using the methanesulfonic acid as a catalysts. Both CMPs have high thermal stability and decomposition temperature reaches above 596 and 248 °C under nitrogen atmosphere, respectively. By right of porous morphology and electron-donating nitrogen, as well as electron-rich π-conjugated structures, the adsorption performance for iodine vapor on the CMPs is very excellent, which can reach 441% and 312%. In addition, fluorescence studies showed that the two CMPs exhibited high fluorescence sensitivity to electron-deficient iodine, o-nitrophenol (o-NP), and picric acid (PA) via fluorescence quenching.

To explore the mechanism of extraction and enrichment of three nitrophenol isomers by charge-transfer supramolecular synergistic three-phase microextraction system, a charge transfer supramolecular-mediated hollow fiber liquid-phase microextraction (CTSM-HF-LPME) combined with high-performance liquid chromatography-ultraviolet detector (HPLC–UV) method was established for the determination of real environmental water samples. In this study, the three nitrophenols (NPs) formed charge-transfer supramolecules with electron-rich hollow fibers, which promoted the transport of NPs in the three-phase extraction system and greatly increased the EF s of NPs. The relationships between the EF s of NPs and their solubility, p K a , apparent partition coefficient, equilibrium constant, and structural property parameters were investigated and discussed. At the same time, most of factors affecting the EF s of NPs were investigated and optimized, such as the type of extraction solvent, pH value of sample phase and acceptor phase, extraction time, and stirring speed. Under optimal conditions, the EF s of o- nitrophenol, m -nitrophenol, and p -nitrophenol were 163, 145, and 87, respectively. With good linearity in the range of 5 × 10 −7  ~ 1 µg/mL, and the limit of detection of 0.1 pg/mL, the relative standard deviations of the method precision were lower than 7.4%, and the average recoveries were between 98.6 and 106.4%. This method had good selectivity and sensitivity, satisfactory precision, and accuracy and had been successfully applied to the trace detection of real water samples.

A theoretical assessment of the o-nitrophenol adsorption on layered double hydroxides containing different metallic species (Ca-Al, Ni-Al and Zn-Al) was performed. Experimental o-nitrophenol adsorption isotherms obtained at different adsorption temperatures with these layered double hydroxides were analyzed using a statistical physics monolayer model. Model calculations showed that the o-nitrophenol aggregation could occur with a high degree. It was estimated that the o-nitrophenol adsorption implied a non-flat orientation on all adsorbent surfaces and this process was multi-molecular. It was also demonstrated that there was no significant difference on the o-nitrophenol adsorption capacities of tested adsorbents, which varied from 77 to 135, 95 to 122 and 74 and 130 mg/g for Ca-Al, Ni-Al and Zn-Al layered double hydroxides, respectively. This finding suggested that the incorporation of Ca-Al, Ni-Al and Zn-Al in the layered double hydroxide structure played a similar role to adsorb o-nitrophenol molecules from aqueous solution. Calculated adsorption energies and thermodynamic functions confirmed an exothermic adsorption with the presence of physical-based interaction forces. This paper highlights the importance of reliable theoretical calculations based on statistical physics theory to contribute in the understanding of the adsorption mechanisms of a relevant water pollutant using layered double hydroxides as promising adsorbents for industrial applications.