Phosphorus In Aqueous Solution Research Articles

Lanthanum-doped chitosan-based polyacrylamide double network hydrogels for adsorption of phosphorus from wastewater.

Excessive phosphorus in aqueous solutions can cause eutrophication, which can harm aquatic organisms and pose a risk to the safety of drinking water for humans. The Chitosan/Polyacrylamide/Lanthanum (CS/PAM/La) hydrogel was designed to get rid of phosphate from aqueous solutions. La (III) was used to enhance the capacity of adsorption of CS. Polyacrylamide was used to enhance the mechanical properties of CS. The results showed that the adsorption capacity of CS/PAM/La hydrogel for phosphate was increased compared with that of CS. When pH of 5.0, the adsorption capacity was 80.07mg-P/g. In addition, after five adsorption and desorption cycles, the adsorption efficiency remained above 90%. The mechanism of phosphate adsorption on CS/PAM/La material was analyzed using a mass transfer factor model (MTF) and the possible structure of CS/PAM/La hydrogel was calculated by density functional theory calculation (DFT). The application of CS/PAM/La composite hydrogel for removal of phosphate from actual wastewater was investigated, and the results met the requirement of national standard.

First principles study on the adsorption of lead ions by black phosphorus in aqueous solution

In this paper, the adsorption behavior of intrinsic black phosphorus (BP) and BP doped with five atoms of O, Si, S, Cu and Zn on Pb[Formula: see text] in aqueous solution was investigated by using the first principle of nature. The formation energy was calculated to be the smallest for Si-doped BP at 2.608[Formula: see text]eV, indicating the best structural stability. The adsorption energy was calculated and showed that the doped BP is more capable of adsorbing Pb[Formula: see text] than the intrinsic BP, with the S-doped BP having the strongest adsorption capacity of 0.151[Formula: see text]eV. The density of states was calculated and showed that the bandgaps of the doped BP are all smaller than the 1.3[Formula: see text]eV of the intrinsic BP, indicating that the doping can improve electrical conductivity of the adsorption system. The charge transfer was calculated and showed that S doping, O doping, Cu doping and Zn doping enhanced the ionic bonding between BP surface atoms and Pb[Formula: see text], while Si doping weakened the ionic bonding. The charge transfer of S doping was the largest at 1.371[Formula: see text]e, indicating that S-doped BP had the strongest ability to adsorb Pb[Formula: see text].

Sustainable phosphorus adsorption and recovery from aqueous solution by a novel recyclable Ca-PAC-CTS

Phosphorus removal has been explored for a long time, however sustainable phosphorus adsorption and recovery with adsorbents recycling is rarely reported. This work proposes a sustainable phosphorus recycling route with calcium-modified powdered activated carbon with chitosan (Ca-PAC-CTS). The morphology, functional groups and crystal structure of Ca-PAC-CTS were characterized. The maximum phosphorus adsorption capacity was 16.73 mg/g Ca-PAC-CTS with Langmuir model at 298 K. Stable phosphorus sorption on Ca-PAC-CTS could be observed at the large range of pH (4– 10) when coexisting with NO3−, SO42−, Cl− and F−, except HCO3−. 98.95 % The recovery of adsorbed phosphorus could get to 98.95 % using 0.05 M sulfuric acid solution, and the phosphate adsorption efficiency through Ca-PAC-CTS remained to be more than 80 % after five adsorption-desorption cycles, suggesting that Ca-PAC-CTS was one of the promising adsorbents for sustainable removal and recovery of phosphorus in aqueous solution.

Iron(Ⅲ)-modified resin YZS60 combined with laser-induced fluorescence spectra for the detection of phosphorus after solid-phase extraction in aqueous solutions

Phosphorus elements were extracted from aqueous solutions by iron-modified chelate resin YZS60. The characterization of the iron-modified chelate resin by using scanning electron microscopy, energy disperse spectroscopy, Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy showed that iron(Ⅲ) was successfully grafted onto the iminodiacetic acid functional group of chelating resin. The resin chelated with phosphorus emitted strong fluorescence after excited by very low power semiconductor laser, which was used for the detection of phosphorus in aqueous solutions, resulting in improving the sensitivity significantly for the detection of phosphorus in aqueous solutions. The fluorescence intensities of the chelates were proportional to the phosphorus concentrations with highly linear correlation coefficients R2 = 0.991 and the limit of detection of 0.018 mg/L was achieved. This work provides a simple, low-cost, and non-destructive method for the extraction and detection of phosphorus in aqueous solutions.

Efficient removal of nitrogen and phosphorus in aqueous solutions using modified water treatment residuals-sodium alginate beads.

A high-performance sorbent, modified water treatment residuals-sodium alginate beads (WTR-SA beads), was prepared through a series of salt and combined thermal roasting composite modification between water treatment residuals and sodium alginate. The properties of modified WTR-SA beads composites were characterized by SEM-EDS, FT-IR, XRD, and BET. The adsorption performance of WTR-SA beads was investigated in removing nitrogen and phosphorus from wastewater. Compared to the unmodified WTR, the removal efficiency of nitrogen and phosphorus onto the modified WTR-SA beads was increased from 22.34 and 77.13% to 95.14 and 98.31%, respectively. The adsorption capacities of nitrogen and phosphorus onto the modified WTR-SA beads were reach a maximum of 2.52 mg/g and 6.45 mg/g, respectively. The adsorption behavior can be well described using a quasi-second-order kinetic model and Langmuir isotherm model. The thermodynamic properties of nitrogen adsorption indicated that the adsorption was spontaneous and exothermic. On the contrary, the adsorption process of phosphorus is an endothermic reaction. The adsorption of nitrogen by modified WTR-SA beads is mainly carried out through ion exchange and hydroxyl complexation, and ion exchange plays a major role in it. While, the adsorption of modified WTR-SA beads on phosphorus is affected by three actions: ligand exchange, chemical precipitation, and ion exchange, which ligand exchange is the main effect. Based on these results, it can be concluded that the modified WTR-SA beads are a high efficiency adsorbent for removing nitrogen and phosphorus from domestic and industrial wastewater.

Development of polyaminated chitosan-zirconium(IV) complex bead adsorbent for highly efficient removal and recovery of phosphorus in aqueous solutions

The aim of this work is to examine the adsorption performance and mechanism of phosphorus (P) onto polyethyene polyamine (PEPA) grafted chitosan-zirconium(IV) composite beads (CS-Zr-PEPA) from aqueous solutions. The morphology, functional groups, and surface area of the CS-Zr-PEPA beads were characterized by SEM, FTIR, and BET analysis. Batch adsorption experiments were conducted via different operating parameters such as solution pH, initial phosphate concentration, co-existing anions and temperature. The adsorption kinetics, equilibrium isotherms and adsorption stability of the adsorbent were scrutinized. In comparison with other CS-based beads, the CS-Zr-PEPA had a greater affinity towards P and exhibited a maximum adsorption capacity of 103.96 mg-P/g predicted by Langmuir mode. The reusability studies of CS-Zr-PEPA beads were carried out. The CS-Zr-PEPA beads exhibit preferable sequestration of P through specific interactions, as further demonstrated by studying physicochemical characteristics of the virgin beads and P-adsorbed beads using X-ray photoelectron spectroscopy (XPS). The column performance of CS-Zr-PEPA beads was tested with P-containing wastewater. Results indicated that the developed CS-Zr-PEPA composite beads could be utilized as a promising adsorbent for effective removal and recovery of P from water and wastewater.

Novel iron manganese oxide modified mulberry biochar for the adsorption of phosphorus in aqueous solution

Novel iron manganese oxide modified mulberry biochar for the adsorption of phosphorus in aqueous solution

Ultrafast Cathodic Exfoliation of Few-Layer Black Phosphorus in Aqueous Solution

Preparing few-layer black phosphorus flakes, in a scalable, fast, and benign way, is a key step to promote both the fundamental research and practical applications of black phosphorus. Although the electrochemically assisted liquid exfoliation of bulk black phosphorus is a promising strategy, it is still challenging to obtain few-layer black phosphorus flakes in polar protic solvent through cathodic exfoliation. In this work, we demonstrate an ultrafast approach to exfoliate bulk black phosphorus, under a cathodic potential, in an aqueous solution of hexadecyltrimethylammonium chloride. Particularly, the exfoliation can be trigged within ∼20 s, and the obtained flakes exhibit satisfactory quality. Further detailed mechanical explorations reveal that the cathodic intercalation of hexadecyltrimethylammonium cations and their subsequent decomposition contribute to the ultrafast expansion and exfoliation of bulk black phosphorus crystals. In addition, the as-exfoliated flakes show improved stability due to the protection of hexadecyltrimethylammonium chloride. This exfoliation method, together with the findings, should shed light on the development of new exfoliation methods for preparing few-layer black phosphorus flakes in various liquid systems, thus facilitating the future applications of black phosphorus.

Enhancement of bauxite residue as a low-cost adsorbent for phosphorus in aqueous solution, using seawater and gypsum treatments

Bauxite residue (red mud), the by-product produced in the alumina industry, is being produced at an estimated global rate of approximately 150 Mt per annum. Due to its highly alkaline nature, many refineries use neutralisation techniques such as mud farming (atmospheric carbonation), direct carbonation using carbon dioxide or reactions with seawater, to treat the bauxite residue and reduce its alkalinity prior to disposal in the BRDA (bauxite residue disposal area). Applying a treatment can render the bauxite residue non-hazardous and may also prepare the bauxite residue for reuse, particularly as an adsorbent. In this study, gypsum and seawater treatments were applied to the various bauxite residue samples obtained and the effects on its mineral, elemental and physiochemical properties were examined, as well as the effect on its phosphorus (P) adsorption capacity. It was found that in addition to reducing the alkalinity of all bauxite residue samples used, the P adsorption capacity was also enhanced following amendment with seawater or gypsum, particularly with gypsum. A positive correlation was detected between P adsorption and both Ca and CaO. A negative correlation was detected between the P adsorption and pH of the media. Fitting the data obtained from a batch adsorption experiment to the Langmuir adsorption isotherm, the maximum adsorption capacity was estimated to range from 0.345 to 2.73 mg P per g bauxite residue, highlighting the re-use potential for bauxite residue as an adsorbent for P.

Facile and effective synthesis of adsorbent - utilization of yeast cells immobilized in sodium alginate beads for the adsorption of phosphorus in aqueous solution.

We compared the adsorption efficiency of phosphates onto Ca-alginate immobilized yeast and freely suspended yeast under different conditions of pH and temperature. The results clearly demonstrated that the adsorption efficiency onto Ca-alginate immobilized yeast was better than that of freely suspended yeast, and reached a maximum at pH 9.17 and 35 °C. Scanning electron microscopy was used to characterize the morphology of Ca-alginate immobilized yeast. Fitting the adsorption equilibrium data to existing models showed that the Freundlich isotherm model described the process better than the Langmuir model, and the process of adsorption followed pseudo-first-order kinetics. During the initial period of experiment, external diffusion was a key rate-controlling step, and intraparticle diffusion also contributed to the mass transport. The thermodynamic properties (Gibbs free energy change of -15.143 kJ/mol, enthalpy change of 274.118 kJ/mol, and entropy change of 290 J/(mol K)) indicated that the adsorption process was endothermic.

Adsorption Performance of a Novel Complex Absorbent to Phosphorus in Aqueous Solution

In the paper, a new composite absorbent was prepared by diatomite and zeolite. The structure of the prepared composite absorbent was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron micrograph (SEM) and Energy dispersive spectrometer (EDS). In addition, the kinetics and thermodynamics properties of the new composite absorbent to the phosphate in aqueous solution were investigated as well. The results showed that, new crystalline phases and fresh bonds might be formed in the prepared composite absorbent. The metallic contents in materials interacted with diatomite, leading to the formation of inorganic polymerized silicon complex and the increasing of the element content of calcium, magnesium, aluminum and ferrum in the new composite absorbent. It was found that the pseudo-second-order equation could fit the adsorption kinetics well, and the adsorption isotherms could be qualified by the Langmuir equation.

Carbonization of wood biomass loaded with calcium and its use in phosphorus removal from an aqueous solution

Wood biomass charcoal loaded with calcium was produced and the effects of the conditions of calcium-loading and carbonization on the product properties were examined. Calcium on charcoal was mainly CaCO 3 . In addition, the effects of calcium loading onto charcoal were examined for the removal of phosphorus from an aqueous solution. The amount of phosphorus removed increased with calcium loading while the amount removed by charcoal without calcium loading were small. Calcium phosphate would be produced on charcoal by the reaction of calcium on charcoal with phosphorus in aqueous solution. [TANSO 2012 (No. 254) 169–75.]

カルシウムと木質バイオマス炭素化物の複合と水中リン除去への利用

Wood biomass charcoal loaded with calcium was produced and the effects of the conditions of calcium-loading and carbonization on the product properties were examined. Calcium on charcoal was mainly CaCO3. In addition, the effects of calcium loading onto charcoal were examined for the removal of phosphorus from an aqueous solution. The amount of phosphorus removed increased with calcium loading while the amount removed by charcoal without calcium loading were small. Calcium phosphate would be produced on charcoal by the reaction of calcium on charcoal with phosphorus in aqueous solution.

Synergistic effect of vanadium–phosphorus promoted oxidation of benzylic alcohols with molecular oxygen in water

The synergistic effect of vanadium–phosphorus in aqueous solution is crucial to ensure high efficiency for oxidation of benzylic alcohols with molecular oxygen in water catalyzed by VOPO4/TEMPO (2,2,6,6-tetramethylpiperidyl-1-oxy).

Phosphorus mineralization for resource recovery from wastewater using hydrothermal treatment

We investigated the resource recovery of phosphorus from aqueous media containing various inorganic phosphorus compounds by hydrothermal mineralization treatment. The hydrothermal treatment was carried out for the model wastewaters containing 2000 mg/dm3 of phosphorus in forms of PVO43-, PIIIO33-, PIO23- or a mixed aqueous solution of PIIIO33- and PIO23- with mineralizer Ca(OH)2. The phosphorus concentration in the treated water, which contained PVO43-, was less than 0.1 mg/dm3. On the other hand, the hydrothermal mineralization treatments with solid-liquid separation under hydrothermal conditions were required for the treatment of PIIIO33- and PIO23-, in order to accomplish the national effluent standard of Japan (16 mg/dm3). In this case, the phosphorus concentration in the solution treated under the optimal conditions was 0.20 mg/dm3. Thus, the hydrothermal mineralization with Ca(OH)2 is recommended as one of the detoxification and recovery techniques of phosphorus in aqueous solution.

Phototaxis index of Daphnia carinata as an indicator of joint toxicity of copper, cadmium, zinc, nitrogen and phosphorus in aqueous solutions

An orthogonal design method was used for examining the responses of Daphnia carinata to 16 combination mixtures of copper, cadmium, zinc, nitrogen and phosphorus in synthetic solutions. Phototaxis index ( I p ), mobilization inhibition percentage (MIP) and mortality percentage (MP) were used as test endpoints for toxicity assessment. The results show that Cu and Cd were the dominant toxicants that affected the D. carinata in the test solutions. However, the contribution of nitrogen, relative to other components, to the overall toxicity to D. carinata could increase over time. It was found that three toxicity parameters ( i.e . I p , MIP and MP) used in this study were significantly interrelated (at p < 0.003 level). Cluster analysis also indicates that there was a general agreement between the toxicity indicated by I p and the universally accepted test endpoints (MIP or MP); MIP and MP represent the universally accepted test endpoints, i.e . mobilization inhibition and mortality. These results suggest that the phototaxis index of D. carinata is an appropriate test endpoint for toxicity testing of environmental samples. This has implications for developing rapid, non-destructive bioassays for ecotoxicological assessment of aquatic environments.

Electrolytic formation of phosphine from red phosphorus in aqueous solutions

Data are presented on the current-voltage behavior of red phosphorus suspensions at gold, platinum, lead, and cadmium cathodes in a 1.0 M Na2CO3 solution. In experiments with a red phosphorus suspension in alkaline solutions, the formal current efficiency for phosphine was 3–8%, while the current efficiency for hydrogen approached 100%. Similar results were obtained with cathodes produced by pressing a mixture of red phosphorus and graphitized soot. Sonication was found to accelerate the reaction between suspended phosphorus and NaOH, but it did not raise the electrolysis efficiency. The conclusion is made that red phosphorus is electrochemically inactive and that phosphine is formed through the reaction of phosphorus with the alkali present in increased concentration at the cathode.

Removal capacity of water plant alum sludge for phosphorus in aqueous solutions

Alum sludge, which is a waste product from a potable water treatment process, was tested as an inexpensive alternate adsorbent for phosphorus in wastewater. The sludge was composed dominantly of sand size aggregates, and could remain stable in aqueous media. The majority of reactive Al in alum sludge was present as an amorphous phase, and seemed to be the major absorbent for P. The batch sorption test showed that the removal of P was influenced by the solubility of Al, Fe and organic carbon depending on pH condition. The acidic condition favored the removal of P, and there was a side effect in the P removal process such as dissolution of Al and organic C at acidic (pH < 4) and alkaline (pH < 8) conditions. The pH range from 4 to 6 was effective for all inorganic and organic phosphates with a low solubility of Al and organic C. The maximum adsorption capacity of alum sludge was calculated as 25,000 mg/kg for orthophosphate, and followed the order: orthophosphate > pyrophosphate > triphosphate > organic phosphate (adenosin). From the column test with a 30 mg/L orthophosphate solution at a flow rate of 3.0 ml/min, the alum sludge removed P to less than 1.0 mg/L over 250 pore volumes at initial pH 4, and 200 pore volumes at initial pH 5, respectively.

Separation of inorganic phosphorus from municipal wastewater by solvent extraction with primary amine in the presence of sodium molybdate

Effective extraction and separation of inorganic phosphorus from municipal wastewater with primary amine as a solvent in the presence of sodium molybdate was studied. The optimum extraction acidity was found to be at pH 6–7. When the content of inorganic phosphorus in aqueous solutions is in the range of 0–300 mg L−1, the quantitative extraction of the inorganic phosphorus can be obtained with 1% primary amine in n-heptane solution and a phase ratio of 1:1 in the presence of 10 g L−1 Mo. Over 75% organic phosphorus in wastewater cannot be extracted by primary amine. The loaded organic phase can be stripped quantitatively with NaOH solution and less than 20% organic phosphorus in the organic phase can be stripped. The resultant aqueous solution after stripping is used directly for colorimetric determination of inorganic phosphorus.

Determination of phosphorus in aqueous solution via formation of the phosphoantimonylmolybdenum blue complex. Re-examination of optimum conditions for the analysis of phosphate

This paper describes an investigation of the conditions affecting the determination of phosphate using the reduced phosphoan-timonylmolybdic acid method. The aim was to develop a determination method with faster kinetics than the original procedure of Murphy and Riley, for automation using flow-injection analysis. Optimum colour formation was found to occur at [H +] [MoO 2− 4] ratios between 50–80 at all pH values tested (0.36–1.06). The maximum rate of formation occurs at a sol[H +] [MoO 2− 4] ratio of 70 within a pH range of 0.57–0.88 when an antimony concentration greater than 0.06 mM and ascorbic acid concentration greater than 0.009 M in the final solution are used. Full colour development occurs within 0.8–1 min. The ascorbic acid reagent was found to be stable for 30 days. The results of the study indicated that by suitable selection of reagent conditions, rapid chromophore development can be achieved.