Ultrahigh-porosity Ranunculus-like MgO adsorbent coupled with predictive deep belief networks: A transformative method for phosphorus treatment.

Phosphorus is a nonrenewable material with a finite supply on Earth; however, due to the rapid growth of the manufacturing industry, phosphorus contamination has become a global concern. Therefore, this study highlights the remarkable potential of ranunculus-like MgO (MO4-MO6) as superior adsorbents for phosphate removal and recovery. Furthermore, MO6 stands out with an impressive adsorption capacity of 596.88 mg/g and a high efficacy across a wide pH range (2-10) under varying coexisting ion concentrations. MO6 outperforms the top current adsorbents for phosphate removal. The process follows Pseudo-second-order and Langmuir models, indicating chemical interactions between the phosphate species and homogeneous MO6 monolayer. MO6 maintains 80 % removal and 96 % recovery after five cycles and adheres to the WHO and EUWFD regulations for residual elements in water. FT-IR and XPS analyses further reveal the underlying mechanisms, including ion exchange, electrostatic, and acid-base interactions. Ten machine learning (ML) models were applied to simultaneously predict multi-criteria (sorption capacity, removal efficiency, final pH, and Mg leakage) affected by 15 diverse environmental conditions. Traditional ML models and deep neural networks have poor accuracy, particularly for removal efficiency. However, a breakthrough was achieved by the developed deep belief network (DBN) with unparalleled performance (MAE = 1.3289, RMSE = 5.2552, R2 = 0.9926) across all output features, surpassing all current studies using thousands of data points for only one output factor. These captivating MO6 and DBN models also have immense potential for effectively applying in the real water test with error < 5 %, opening immense horizons for transformative methods, particularly in phosphate removal and recovery.

Ionic fluid as a novel cleaning agent for the control of irreversible fouling in reverse osmosis membrane processes.

While a variety of chemical cleaning strategies has been studied to control fouling in membrane-based water treatment processes, the removal of irreversible foulants strongly bound on membrane surfaces has not been successful. In this study, we firstly investigated the diluted aqueous solutions of ionic fluid (IF, 1-ethyl-3-methylimidazolium acetate) as a cleaning agent for three model organic foulants (humic acid, HA; bovine serum albumin, BSA; sodium alginate, SA). The real-time monitoring of cleaning progress by optical coherence tomography (OCT) showed that fouling layer was dramatically swelled by introducing IF solution and removed by shear force exerted during cleaning. This phenomenon was induced due to the pre-existing interactions between organic foulants were weakened by the intrusion of IF into the fouling layer, which was analyzed by the measurement of adhesion forces using atomic force microscopy (AFM). In the experiments with model foulants and wastewater effluent, IF was added to alkaline cleaning agents (NaOH) to verify the applicability to be supplemented in commercial cleaning agents, and resulted in the significantly enhanced control of irreversible membrane fouling. Implication of utilizing recyclable IF with negligible volatility is that environmental effects of membrane cleaning solutions could be minimized by decreasing usage of cleaning chemicals, while increasing the cleaning efficiency.

Incorporation of iron (oxyhydr)oxide nanoparticles with expanded graphite for phosphorus removal and recovery from aqueous solutions.

In this work, iron (oxyhydr)oxide nanoparticle-doped expanded graphite (IO/EG-1 and IO/EG-2) was prepared via a hydrothermal reaction and applied for the phosphorus adsorption in the aqueous solutions. The analysis of scanning electron microscopy (SEM) and X-ray diffraction (XRD) verified the successful fabrication of IO/EGs, and iron (oxyhydr)oxide nanoparticles became more crystalized according to the calcination at high temperature (IO/EG-2). The maximum adsorption capacity of IO/EG-1 was considerably higher (7.30 mg/g) than that of IO/EG-2 (0.70 mg/g) mainly due to the electrostatic interaction between the negatively charged phosphate ions with iron (oxyhydr)oxides. At the neutral pH, IO/EG-1 exhibited more positively charged than IO/EG-2, which the iso-electric points (IEP) were pH of 9.1 and 6.0, respectively. The thermodynamic study also suggested that the phosphorus adsorption energy of IO/EG-1was considerably favorable (-12.13 kJ/mol) than that of IO/EG-2 (-7.43 kJ/mol). The regeneration of IO/EG-1 were efficiently achieved by a simple extraction using an alkaline solution such as NaOH. Overall, our study suggested that the prepared IO/EGs could be used as good adsorbents for the phosphorus recovery from aqueous solutions.

Municipal wastewater treatment by forward osmosis using seawater concentrate as draw solution.

Forward osmosis (FO) has been used in the wastewater treatment due to its advantages including low energy consumption and low membrane fouling. In this study, real municipal wastewater was concentrated by FO process using seawater concentrate as draw solution (DS). The influences of operating conditions such as temperature, flow velocity and sewage pre-filtration on water flux were investigated. Chemical oxygen demand, total nitrogen, ammonia nitrogen and total phosphorus could not be enriched by 4 times while sewage was reduced to 1/4 volume. Excitation and emission matrix fluorescence spectrum showed that a fraction of dissolved organic compounds in sewage transported across membrane into DS. Membrane fouling was evaluated by scanning electronic microscope analysis that a dense cake layer was formed on the membrane surface after sewage filtration. However, water flux of the fouled membrane was highly recovered after 1 h of physical cleaning.

Presence of Fe-Al binary oxide adsorbent cake layer in ceramic membrane filtration and their impact for removal of HA and BSA.

To enhance the removal of natural organic matter (NOM) in ceramic (Ce) membrane filtration, an iron-aluminum binary oxide (FAO) was applied to the ceramic membrane surface as the adsorbent cake layer, and it was compared with heated aluminum oxide (HAO) for the evaluation of the control of NOM. Both the HAO and FAO adsorbent cake layers efficiently removed the NOM regardless of NOM's hydrophobic/hydrophilic characteristics, and the dissolved organic carbon (DOC) removal in NOM for FAO was 1-1.12 times greater than that for HAO, which means FAO was more efficient in the removal of DOC in NOM. FAO (0.03 µm), which is smaller in size than HAO (0.4 µm), had greater flux reduction than HAO. The flux reduction increased as the filtration proceeded because most of the organic foulants (colloid/particles and soluble NOM) were captured by the adsorbent cake layer, which caused fouling between the membrane surface and the adsorbent cake layer. However, no chemically irreversible fouling was observed on the Ce membrane at the end of the FAO adsorbent cake layer filtration. This means that a stable adsorbent cake layer by FAO formed on the Ce membrane, and that the reduced pure water flux of the Ce membrane, resulting from the NOM fouling, can easily be recovered through physicochemical cleaning.

Evaluation of natural organic matter adsorption on Fe-Al binary oxide: Comparison with single metal oxides.

The adsorption characteristics of three types of standard natural organic matter (NOM) on iron-aluminum (Fe-Al) binary oxide (FAO) and heated aluminum oxide (HAO) under natural surface water condition were investigated using various adsorption isotherms and kinetic models. FAO was synthesized by Fe oxide and Al oxide, mixed using the sol-gel hydrothermal method, and aluminum sulfate was used to make HAO. The amount of adsorbed NOM was increased to 79.6 mg g-1 for humic acid (HA), 101.1 mg g-1 for sodium alginate (SA) in the FAO, but the maximum adsorption capacity of bovine serum albumin (BSA) (461.3 mg g-1) was identified on the HAO. The adsorption of HA, BSA, and SA dramatically increased (>70%) on FAO in 5 min and HA was significantly removed (90%) among the three NOM. Mutual interaction among the adsorbed NOM (BSA) occurred on the HAO surface during adsorption due to formation of monolayer by protein molecules at neutral pH. The pseudo second order clearly represented the adsorption kinetics for both adsorbents. The equilibrium isotherm data of FAO was better exhibited by the Langmuir isotherm model than by the Freundlich isotherm, but HAO was a slightly non-linear Langmuir type. Also, the free energy, enthalpy, and entropy of adsorption were determined from the thermodynamic experiments. Adsorption on FAO was spontaneous and an exothermic process. Fluorescence excitation-emission matrix (FEEM) spectra were used to elucidate the variation in organic components. The results obtained suggests that the significant changes in the surface property of the adsorbent (large surface area, increased crystalline intensity, and fine particle size) were effectively determined by the Fe-synthesized Al oxide mixed using the sol-gel hydrothermal method. The results also suggest that the changes enhanced the adsorption capacity, whereby three NOM were notably removed on FAO regardless of NOM characteristics (hydrophobic and hydrophilic).

Improvement of bacterial hydrogen production by ATP in mixed organic compounds extracted from Rhodobacter sphaeroides aerobically cultured under dark conditions.

The aim of this study was to increase the hydrogen production of recombinant Escherichia coli harboring HupSL hydrogenase by supplementing physiologically activating compounds extracted from Rhodobacter sphaeroides cultured under anaerobic dark condition after treating them with dimethyl sulfoxide, and the 0.5% extracts contained 4×10(-8)M ATP, which was 100-fold higher than that in the extracts from E. coli. In addition, it was found that the hydrogen production from recombinant E. coli harboring HupSL hydrogenase isolated from R. sphaeroides was doubled under anaerobic conditions when it was supplemented by the extracts from R. sphaeroides cultured aerobically in dark conditions, and this also showed consistent pattern with the increased level of HupSL hydrogenase expression. Therefore, we conclude that the mixed organic compounds extracted from R. sphaeroides have an ATP which enhances the hydrogen production by increasing the amount of HupSL hydrogenase.

Evaluation of whole lysosomal enzymes directly immobilized on titanium (IV) oxide used in the development of antimicrobial agents.

Lysosomal enzymes isolated from egg white were directly immobilized on titanium (IV) oxide (TiO(2)) particles using shaking methods (150 rpm, room temperature, 10 min), and the immobilization efficiency, activity, and stability of lysosomal enzymes immobilized on TiO(2) were evaluated. Of the various mass ratios (w/w) of lysosomal enzymes to TiO(2) tested, we found that 100% immobilization efficiency was observed at a ratio of 1:20 (enzymes:TiO(2); w/w). Furthermore, the antimicrobial activities of the immobilized lysosomal enzymes were confirmed using viable cell counts against Escherichia coli. Our results showed that the antimicrobial activity of immobilized lysosomal enzymes is stable and can be maintained up to one month, but the antimicrobial activity of free enzymes without immobilization completely disappeared after five days in storage. In addition, enhanced immobilization efficiency was shown in TiO(2) pretreated with a divalent, positively charged ion, Ca(2+), and the antimicrobial activity for E. coli increased as a function of increasing ratio of immobilized enzymes. However, K(+), a monovalent, positively charged ion, did not have any positive effect on immobilization or antimicrobial activity. Finally, we suggest that activity and stability of immobilized lysosomal enzymes can be maintained for a longer time than those properties of free lysosomal enzymes.