Adsorbent For Nitrate Removal Research Articles

Effects of Fe3O4 magnetic nanoparticles on nitrate removal efficiency: an optimization study using response surface methodology

ABSTRACT The nitrate contamination of water resources is a serious environmental problem, which may be solved by nitrate sorption onto magnetic nanoparticles. In this study, the effects of Fe3O4 magnetic nanoparticles on nitrate removal were investigated. Fe3O4 was synthesized by a co-precipitation method and used as an adsorbent for nitrate removal. pH, adsorbent dosage, and contact time were considered as the main variables. The effective ranges of these variables were chosen as pH = 4–10, adsorbent dose = 0.5–1.5 g/L, and contact time = 30–90 min. The optimization study was conducted using the Box–Behnken statistical design method. According to the analysis of variance table, it can be concluded that the model is ‘significant’ and the value of R2 was 0.99. The results of the study show that the maximum nitrate removal efficiency was about 91.02%. This was obtained at pH 7, using a dose of 1.3 g/Lof Fe3O4, and a contact time of 28 min.

Adsorptive removal of nitrate from aqueous solution using a MnFe2O4@zeolite-activated carbon magnetic nanocomposite: isotherm and kinetics studies

Nitrate elimination from groundwater and surface water has received growing attention in recent years, as its gradual accumulation severely endangers freshwater reserves around the world.

Mechanistic insights of nitrate removal by MgFe/layered double hydroxides prepared by different synthesis pathways

In this study, a layered MgFe/double hydroxide (MgFe/LDH) adsorbent for nitrate removal from simulated systems was developed and investigated. Three different synthesis methods were used: coprecipitation at constant pH (CC), conventional hydrothermal (CH), and pre-ultrasonic followed by conventional hydrothermal (UCH). The XRD results indicated that all synthesized samples presented the characteristic structure of LDHs. The analysis of FT-IR spectra before and after nitrate adsorption allowed the analysis of NO3−MgFe/LDH interaction in different adsorbents. Adsorption kinetics showed that all adsorbents reached equilibrium around 120 min, with the adsorption capacity being 6.970, 6.690, and 5.610 mg g−1 for the UCH, CH, and CC, respectively. Pseudo-second order and Langmuir models were the best models for describing the kinetics and isotherm data. The highest maximum adsorption capacity was reached at 330 K, with a value of 21.18 mg g−1 for the UHC. Thermodynamic analysis indicated that the adsorption of nitrate was exothermic and spontaneous despite the system. The results of this study suggest that the MgFe/LDH adsorbent synthesized by the UCH method with hydrothermal treatment presents a promising and efficient way of removing nitrate from polluted water, with potential application in the purification of water for human and environmental use.

Removal of nitrate from aqueous solution by using orange peel and wheat straw

Increasing nitrate contamination in water bodies causing various human health and environmental challenges. Nitrate enters the human body through the drinking water and causes number of health issues such as methaemoglobinemia, gastric cancer, hormonal imbalance disorder, birth malformations, hypertention etc. when present in high concentration in drinking water. Hence there is strong need for economic and ecofriendly technology to treat the excess nitrate from water.There are chemical and physical methods are available for removal of nitrate but as compare to such methods biological methods are considered to be an effective solution due to its low cost, easy availability and high efficiency. The present study aims to examine the efficiency of orange peel and wheat straw an adsorbent for removal of nitrate from aqueous solution. The batch method was used to study the adsorption. The obtained results from the batch experiment have shown the ability of both the adsorbents in removing nitrate. The optimum bio-adsorption of nitrate over orange peel and wheat straw bio-adsorbent was obtained at contact time = 3 hr., Quantity of adsorbent = 3 g and initial concentration = 700 mg/l. Obtained results from batch experiment found that the orange peel is more efficient than wheat straw for nitrate removal. Adsorption isotherm was described by Langmuir isotherm model and model fitted well.Therefore, the adsorbents are efficient and cost effective in the treatment of nitrate contaminated water.

Using ZrO2 coated sludge from drinking water treatment plant as a novel adsorbent for nitrate removal from contaminated water

This study aimed to produce a novel efficient absorbent using sludge generated from drinking water treatment plants (DWTPs) as a low-cost absorbent and applied to treat nitrate (NO3−) from contaminated water. Before the ZrO2 coating experiment, the drinking water sludge (DWS) from DWTPs was pretreated by thermal treatment (80 °C, 200 °C, and 500 °C). After that, ZrO2 coated drinking water sludge (DWS@ZrO2) was produced by a simple precipitated reaction. The synthesized DWS@ZrO2 was characterized by FTIR, SEM, and EDS with mapping analysis, XRD, and VSM. The results revealed that DWS@ZrO2 could improve the pore filling in the adsorption experiment. The highest nitrate adsorption capacity was achieved (30.99 mg g− 1) at pH 2 with DWS500@ZrO2. Adsorption kinetics indicated that pyrolyzed DWS at 500 °C provided the highest nitrate adsorption capacity, followed by 200 °C, and 80 °C. Thermodynamic results showed that the obtained nitrate removal was an endothermic and spontaneous process. The possible nitrate adsorption mechanism of DWS@ZrO2 could mainly involve pore filling, electrostatic interaction, and ligand exchange. The experimental results suggest that DWS@ZrO2 is a feasible absorbent with high-efficiency, low-cost, high recyclability, and eco-friendly characteristics for treating nitrate in an aqueous solution.

Management and removal of nitrate contamination of water at the source using modified natural nano zeolite

Nitrate is a hazardous substance for human health, the removal of which is an important environmental priority. Therefore, in this study, first, the sources of nitrate pollution of water were investigated, then the structure, role, and application of nanozeolites for the removal of nitrate ions were studied by the analytical method. Also, the presentation of management solutions, identification of polluting industrial sectors, different methods of removal and fabrication of ZSM-5/Fe/Ni nanosorbents, and the determination of optimal conditions for nitrate removal were investigated by experimental design software and graphical analysis of effective parameters. The results of graphical analysis of laboratory method showed us, the highest nitrate removal efficiency at a residence time of 150 minutes, pH 3, 4 g L-1 adsorbent, and 40 mg L-1 nitrate were achieved (%RE:91.5-97.4). Experimental results indicate the high efficiency, absorption capacity, and effectiveness of ZSM-5/Fe/Ni adsorbents for nitrate removal in waters. Finally, the absorbance values or nitrate concentrations between 20-120 mg L-1 were measured by the UV-Vis spectrophotometry. The maximum absorption capacity of ZSM-5/Fe/Ni adsorbents for nitrate was obtained 136.7 mg g-1. The developed method based on a novel ZSM-5/Fe/Ni adsorbents has many advantages such as simple, low cost, high efficiency, and favorite recovery.

Adsorption capacity of nitrate from artificial fertilizers and soil on pyrophyllite

The study at hand presents for the first time the use of pyrophyllite as adsorbent for nitrate removal from soil and artificial fertilizers. A series of column and batch adsorption experiments were conducted to examine the effects of the adsorbent’s various parameters, the contact time, pH of the solution, the initial concentration of nitrate, concentration and adsorbent granulometry. Pyrophyllite fractions of 0.25, 0.50 and 1.00 mm had very similar pH values of aqueous suspensions and were in the weakly basic range. Nitrate adsorption capacity on pyrophyllite expressed by recovery factor values ranges from 93.14 to 99.77%. High recovery factor values from 90.44 to 97.45% for 1, 3, 5 and 8 mL min−1 flow rates were obtained using all pyrophyllite fractions. Nitrate removal was very effective by the contact time of 1 and 2 h, and the recovery factor values were in the range of 90.38–91.47% and 92.15–93.18% for a contact time of 1 h and 2 h, respectively. In addition, elution of nitrate from pyrophyllite was performed using the following solution with different pH values: 1.70 (synthetic gastric juice), 6.40 (rainwater), 7.70 (distilled water), 9.30 and 12.50 (NaOH solution). Elution was very low for all used solutions and was the highest at the pH 9.30. The results show that the use of pyrophyllite for removal of nitrate from artificial fertilizers and soil was an adequate approach because it has a high nitrate adsorption capacity, while the nitrate elution from the pyrophyllite was very low.

A colloid chemistry route for the preparation of hierarchically ordered mesoporous layered double hydroxides using surfactants as sacrificial templates

An efficient synthetic route was developed to prepare hierarchically ordered mesoporous layered double hydroxide (LDH) materials. Sodium dodecyl sulfate (SDS) was used as a sacrificial template to tune the interfacial properties of the LDH materials during the synthetic process. The SDS dose was optimized to obtain stable dispersions of the SDS-LDH composites, which were calcined, then rehydrated to prepare the desired LDH structures. Results of various characterization studies revealed a clear relationship between the colloidal stability of the SDS-LDH precursors and the structural features of the final materials, which was entirely SDS-free. A comparison to the reference LDH prepared by the traditional co-precipitation-calcination-rehydration method in the absence of SDS shed light on a remarkable increase in the specific surface area (one of the highest within the previously reported LDH materials) and pore volume as well as on the formation of a beneficial pore size distribution. As a proof of concept, the mesoporous LDH was applied as adsorbent for removal of nitrate and dichromate anions from aqueous samples, and excellent efficiency was observed in both sorption capacity and recyclability. These results make the obtained LDH a promising candidate as adsorbent in various industrial and environmental processes, wherever the use of mesoporous and organic content-free materials is required.

Strontium Oxide Decorated Iron Oxide Activated Carbon Nanocomposite: A New Adsorbent for Removal of Nitrate from Well Water

In the present study, activated carbon was magnetized by iron oxide and modified by strontium based nanoparticles (FeAC@Sr) to introduce it as an efficient favorable adsorbent for the removal of nitrate ions from underground water. The decorated adsorbent was characterized in terms of size, structure, morphology and composition using scanning electron microscopy, Fourier-transform infrared spectroscopy and energy dispersive X-ray spectroscopy. The equilibrium adsorption data were well fitted and explained by Langmuir isotherm with a maximum adsorption capacity of 87.42 mg g-1 (theoretical value calculated from the Langmuir isotherm model). Regarding adsorption kinetic it was seen that it is fit for pseudo-second-order process with an equilibrium state which was reached at pH 4.0 in 90 min. The results also revealed that the incorporation of positively charged strontium and iron oxide into the activated carbon has triggered removal efficiency for the negatively charged nitrate ions.

Characterizations and nitrate adsorption capacity of Amine-SiO2 material

Amine-SiO2 material (basically on silicon dioxide) was synthesized by the grafting method with triamine silane to form activated amine groups on the surface of SiO2 support and was applied as a novel adsorbent for nitrate removal from aqueous solution. The characterizations of Amine-SiO2 were determined by using TGA, FTIR, BET, SEM. Nitrate adsorption capacity and durability of Amine-SiO2 were compared with the anion exchange resin (Akualite A420 commercial). The results showed that Amine-SiO2 had high nitrate adsorption capacity, ~ 1.14 fold higher than the Akualite A420 ion exchange resin, based on the adsorption efficiency. This might be due to a strong affinity for nitrate ions of the activated amine groups on the surface of SiO2 support. In addition, the experimental results also proved that Amine-SiO2 material had good durability (stable performance after 10 regeneration times).

Synthesis of TiO2/nZVI nanocomposite for nitrate removal from aqueous solution

To develop a new adsorbent for removal of nitrate and to enhance the adsorbent separation from aqueous solution, surface modification of titanium dioxide nanoparticles with nano-zero-valent iron (nZVI) was performed through chemical coprecipitation of magnetic nanoparticles on TiO2 surface. Morphological, structural and magnetic properties of modified adsorbents (TiO2/nZVI) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR) and vibrating sample magnetometer (VSM). To determine the ionic strength effect and optimal removal conditions, the effect of contact time (60–210 min), pH (4–10) and adsorbent dosage (0.5–1.5 g/L) on adsorption efficiency were studied, using response surface method. Obtained results showed that the nitrate removal efficiency decreased with increasing ionic strength. The TiO2/nZVI nanocomposites exhibited a ferromagnetic behavior and its saturation magnetization was 795.28 memu/g. The maximum nitrate removal (98.226%) achieved by modified TiO2 was about 14.65% higher than the unmodified nanoparticles. The optimized adsorption parameters were: adsorbent dosage 0.982 g/L, pH 4.185 and the contact time 150.091 min.

Adsorptive removal of nitrate from wastewater using modified lignocellulosic waste material

Waste lignocellulosic material, namely brewers' spent grain (BSG), was modified by quaternisation, where amino groups were introduced into BSG via the reaction with N,N-dimethylformamide (DMF) and epichlorohydrin. The applicability of the modified BSG (MBSG) for the removal of nitrate ions from model solutions and wastewater was evaluated in batch adsorption experiments. Adsorption of nitrate to the MBSG was confirmed by FTIR analysis of the saturated/spent adsorbent. Fixed bed adsorption column and regeneration studies were performed to determine the regeneration capacity of MBSG. The MBSG had a maximum nitrate adsorption capacity of 22.65 mg g−1 for model nitrate solution, 18.22 mg g−1 for model wastewater and 14.4 mg g−1 for the real wastewater effluent generated from dairy industry. The analysis of the equilibrium data showed that the Freundlich isotherm model provided a slightly better fit to the obtained data than the Langmuir model, indicating multilayer sorption. The data were further analysed by pseudo-first-order and pseudo-second-order kinetic models, and the results revealed that the adsorption followed pseudo-second-order kinetics. The intraparticle diffusion model was used to interpret the mechanism of adsorption, and the results suggest that intraparticle diffusion was not the only process that controlled the adsorption. The adsorption-desorption studies in fixed bed column indicated that MBSG could be regenerated and reused for more than three cycles when model nitrate solutions were used. However, when real dairy industry effluent was used in the fixed bed experiments, the clogging of the column occurred. The applied modification technique was found to be appropriate yielding an effective adsorbent for selective nitrate removal from water.

Adsorption of nitrate from aqueous phase onto nitrogen-doped activated carbon fibers (ACFs)

Rayon-based activated carbon fiber (ACF) was modified with several methods: acetonitrile thermal chemical vapor deposition at 800 °C (8AN) to dope nitrogen element on carbon surface, heat treatment at 950 °C (9.5HT) to convert doped nitrogen species into quaternary nitrogen (N-Q) and steam activation at 800 °C (8ST) to additionally develop pore structure. The modified samples were evaluated as adsorbents for the removal of nitrate from NaNO3 aqueous solution at equilibrium solution pH (pHe) around 3.0. Sequential modification of ACF with 8AN, 9.5HT and 8ST achieved the greatest adsorption capacity at 0.7 mmol/g in all prepared samples. The modified adsorbent was probably included in the greatest group in nitrogen-doped carbonaceous adsorbents for nitrate removal. To inspect the high adsorption capacity, specific surface area, elemental analysis and X-ray photoelectron spectroscopy measurements were conducted comparing with the other prepared adsorbents. Based on the data analysis, some specific surface area and N-Q might play an important role in the adsorptive removal of nitrate.

Pre-evaluation of strong base anion exchange, Amberlite IRA 958-Cl resin for nitrate removal

Abstract High concentration of nitrate in water either in surface or groundwater is an effect from agricultural activities, domestic use and industrial activities. Hence, removing enormous nitrate from water is necessary because it can be hazardous to the human health and aquatic life. The ion exchange resin is the most widely used technology in removing nitrate from water source. In this study, commercial strong anion exchange resin, Amberlite IRA 958-Cl was used to study the efficiency of nitrate removal from aqueous solution in a fixed-bed column experiment. The influence of resin dosage (0.05 to 0.20 g), contact time (1 to 4 hours) and initial nitrate concentration (20, 50, 100 and 200 mg/L) were examined. More than 87% of nitrate removal achieved at 0.1 g (2 g/L) of resin dosage, 3 hours of contact time and 20 mg/L of initial nitrate concentration. This promising result make that Amberlite IRA 958-Cl can become an attractive candidate as adsorbent for nitrate removal.

Adsorptive Removal of Nitrate from Water Using Modified Activated Carbon Fibers

Adsorptive Removal of Nitrate from Water Using Modified Activated Carbon Fibers

Adsorptive Removal of Nitrate from Aqueous Phase Using Steam Activated and Thermal Treated Polyacrylonitrile (PAN) Fiber

Adsorptive Removal of Nitrate from Aqueous Phase Using Steam Activated and Thermal Treated Polyacrylonitrile (PAN) Fiber

On the relationship between the specific heat enhancement of salt-based nanofluids and the ionic exchange capacity of nanoparticles

Nanoparticles have been used in thermal applications to increase the specific heat of the molten salts used in Concentrated Solar Power plants for thermal energy storage. Although several mechanisms for abnormal enhancement have been proposed, they are still being investigated and more research is necessary. However, this nanoparticle-salt interaction can also be found in chemical applications in which nanoparticles have proved suitable to be used as an adsorbent for nitrate removal given their high specific surface, reactivity and ionic exchange capacity. In this work, the ionic exchange capacity mechanism for the nanoparticles functionalization phenomenon was evaluated. The ionic exchange capacity of silica and alumina nanoparticles dispersed in lithium, sodium and potassium nitrates was measured. Fourier-transform infrared spectroscopy tests confirmed the adsorption of nitrate ions on the nanoparticle surface. A relationship between the ionic exchange capacity of nanoparticles and the specific heat enhancement of doped molten salts was proposed for the first time.

Utilization of bare MgO, CeO2, and ZnO nanoparticles for nitrate removal from aqueous solution

The traditional drinking water purification process is inefficient in removing nitrate significantly. Adsorption can be the most practical method for the removal of nitrate from drinking water. In this study, novel MgO, CeO2, and ZnO nanoparticles (NPs) were utilized for nitrate removal. The MgO, CeO2, and Zn NPs were characterized by Fourier transform infrared spectrometry (FT‐IR), scanning electron microscopy‐energy disperse X‐ray (SEM‐EDX), and X‐ray diffractometer (XRD) analysis. The efficiency of nitrate removal was examined through batch adsorption experiments. The influence of various parameters was studied, namely pH (3–8), temperature (15–40°C), time (10–1440 min), and liquid/solid weight ratio (L/S =25 mL/0.025 g). The optimum conditions from mentioned parameters were used in isotherm experiments with initial nitrate concentration (22–220 mg/L). The adsorption kinetics and isotherm data obeyed well Pseudo‐second‐order and linear and Freundlich models, indicating the multi layer‐chemisorption of nitrate ions. The maximum adsorption capacities of nitrate (N‐ ) calculated by final point of isotherm experiments were 86.4 mg/g for MgO, 57.6 mg/g for ZnO, and 58.6 mg/g for CeO2. The thermodynamic parameters ( S°) were evaluated. From the thermodynamic parameters, it is suggested that the adsorption of nitrate on NPs followed the endothermic and spontaneous processes. The desorption potential of MgO, CeO2, and ZnO also showed the stability and reusability. Our findings also revealed that among studied NPs from this study and literature MgO NPs is potentially the best adsorbent for removal of nitrate from aqueous solutions. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018

Nitrate Adsorption from Aqueous Solution by Metal–Organic Framework MOF-5

The present study has been developed to evaluate the feasibility of the metal–organic framework (MOF) as adsorbent for nitrate removal from aqueous solution. The MOF-5 was prepared by solution and solvothermal methods via the self-assembly of primary building blocks using zinc acetate dehydrate and benzene-1,4-dicarboxylate (BDC) at two different conditions, room temperature and 90 °C temperature and with or without tri-ethylamine (TEA) as capping agent. The samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, BET surface area, and UV–Vis spectroscopy. The study of nitrate adsorption was carried out at room temperature on the higher surface area of MOF-5 in pH from 2 to 11, whereas significant difference of nitrate adsorption was observed in acidic pH. Based on the results, nano-sized MOF-5 was demonstrated the potential utility for nitrate removal from water solution.

Nitrate Removal from Groundwater Using Sodium Alginate Doped with Nano-Hydroxyapatite

In the present work, the hydroxyapatite/alginate nano-composite adsorbent was prepared by incorporating nano-sized hydroxyapatite (nHAp) into alginate polymer and uses this adsorbent for removal of nitrate from groundwater. The synthesized nano-composite and pure alginate as well as the pure hydroxyapatite were characterized with Fourier Transform Infrared (FT-IR) spectroscopy to ascertain the functional groups. The adsorption characteristics of nitrate from groundwater on the HAp/Alg nano-composite were optimized under different operational parameters like contact time, pH, adsorbent dosage, initial concentration of nitrate and temperature in batch system. Maximum equilibrium capacity reached 99% of nitrate removal by using the HAp/Alg nano-composite after 240min at pH 3; adsorbent dosage, 2g; initial concentration, 100mg/l and temperature, 20°C. The kinetics studies revealed that the pseudo-second-order kinetic model was able to describe the dynamic behavior of the adsorption process by composite adsorbents used in this work. Also, the Langmuir isotherm model is very well fitted to the equilibrium data. The mechanism of NO3- ions adsorption by the nano-composite adsorbent was described. So, it is concluded that HAp/Alg nano-composite is a relatively efficient and low cost as well as the results validated the feasibility of HAp/Alg nano-composite for highly effective removal of nitrate from an aqueous solution.