Nitrate Adsorption Capacity Research Articles

Reduction of Nitrate Content in Water by the Use of Banana Peels Biochar

The intensification of agricultural, domestic and industrial activities leads to the increasing contamination of groundwater and surface water by nitrates. Indeed, agricultural runoff, septic tank effluents, landfill leachates or wastewater treatment plant effluents contribute to this nitrification, yet drinking water containing high nitrate content can cause health problems. The study examines the improvement of nitrate removal in synthetic water solution by adsorption on banana peel’s activated carbon (BPAC). Different effects of physicochemical parameters, such as the optimal contact time of BPAC in solution, the pH of the nitrate solution, the initial concentration of nitrate solution, the BPAC mass, and the temperature were evaluated. The study revealed that BPAC has a low nitrate adsorption capacity under normal laboratory conditions. However, this adsorption capacity of BPAC increases with increasing of temperature and initial content of nitrate, while it decreases with increasing BPAC mass. For a content of 100 mg/L nitrate solution, the maximum adsorption capacity was 0, 687 mg/g for an equilibrium time of 180 min. Nitrate adsorption is optimal in acidic media (pH=3). The application of kinetic models to the experimental data showed that the mechanism of nitrate adsorption on BPAC obeys pseudo-first order kinetics. The Freundlich isotherm perfectly describes the mechanism of nitrate adsorption on BPAC.

Synthesis of cation exchange resin-supported iron and magnesium oxides/hydroxides composite for nitrate removal in water

In this study, we reported on the concept and practical use of cation exchange resin (CER) for removing anions in water via pretreating the CER with metal salts. The cation exchange resin-supported iron and magnesium oxides/hydroxides composite (Fe-Mg/CER) was synthesized and introduced as a new and potential adsorbent for selective removal of nitrate ion in the water environment. Characteristics of Fe-Mg/CER were determined by techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The results showed that Fe-Mg/CER material had a high nitrate adsorption capacity of 200 mg NO3−·g−1 with a fast equilibrium adsorption time of 30 min at pH 5. In addition, it had good durability of at least 10 times of regeneration, which could be applied to practical water and wastewater treatment.

Cationic Surfactant-Modified Covalent Organic Frameworks for Nitrate Removal from Aqueous Solution: Synthesis by Free-Radical Polymerization.

Development of efficient adsorbents for nitrate removal is vital for tackling increasing nitrate contamination. We report a free-radical polymerization strategy to prepare a cationic surfactant-modified covalent organic framework (DhaTab-S) for removing nitrate ions from aqueous solution. DhaTab-S was prepared by grafting a cationic surfactant diallyldimethylammonium chloride solution on vinyl-containing COF (DhaTab-V). The adsorption capacity for nitrate was pH-dependent with the maximum at pH 6, and the adsorption process was largely influenced by ionic strength. The adsorption equilibrium for nitrate on DhaTab-S was reached within 40 minutes and followed pseudo-second-order kinetics. DhaTab-S showed a nitrate adsorption capacity of 108.8 mg g-1 , which is about 15 times that of COF before surfactant modification. The large adsorption capacity makes DhaTab-S a promising candidate for nitrate removal from aqueous media.

Preparation, Characterization, and Application of Novel Ferric Oxide-Amine Material for Removal of Nitrate and Phosphate in Water

Ferric oxide-amine material was synthesized and applied as a novel adsorbent for nitrate and phosphate removal from aqueous solution. The properties of ferric oxide-amine were examined using TGA, FTIR, BET, SEM, EDX, SEM-mapping, and XRD analysis. The results showed that the adsorption using ferric oxide-amine material reached equilibrium after 30 and 60 min for nitrate and phosphate, respectively. The highest nitrate and phosphate adsorption capacities were 131.4 mg nitrate/g at pH 5-6 and 42.1 mg phosphate/g at pH 6. The effects of adsorbent dosage, initial concentrations of nitrate and phosphate, and adsorption temperature were also investigated. Among the three adsorbents of ferric oxide-amine, ferric oxide, and Akualite A420 ion exchange resin, ferric oxide-amine material had the highest adsorption capacity for nitrate and phosphate removal. These results suggest a great potential use of ferric oxide-amine material for water treatment in practical applications.

Adsorptive performance of lanthanum encapsulated biopolymer chitosan-kaolin clay hybrid composite for the recovery of nitrate and phosphate from water

Nitrate and phosphate are primary pollutants of water/wastewaters for eutrophication and methemoglobinemia diseases, harshly threatening the security of aquatic environments and human health as well as all living beings. The present work investigates the adsorption performance and mechanism of lanthanum encapsulated chitosan-kaolin clay (LCK) hybrid composite was prepared and utilized for the remediation of nitrate and phosphate from water. The fabricated LCK hybrid composite was characterized using XRD, SEM, BET, EDAX, TGA-DTA and FTIR analysis. The removal of nitrate and phosphate onto the LCK composite defined by pseudo-second-order kinetic model whereas the isotherms are described by Freundlich adsorption isotherm model and thermodynamic experiments showed spontaneous and exothermic nature of the adsorption process. Results also demonstrated that the LCK hybrid composite exhibited extremely high nitrate and phosphate adsorption capacity and stability which followed the mechanisms by ion exchange, complexation and electrostatic interactions. Adsorption-desorption experiments revealed that the LCK hybrid composite could be potentially reused with maintaining high adsorption efficiency. This study highlights the novel low-cost, eco-friendly and promising adsorbent for efficient denitrification and dephosphorization from water/ wastewater.

Study on the characteristics of nitrogen-doped activated carbon fibers to remove nitrate ions by multi-factor analysis

A type of rayon-based commercial activated carbon fibers (ACFs), named as KF1500, was modified by thermal chemical vapor deposition (CVD) method to remove nitrate in aqueous solution. Acetonitrile (vapor) was introduced to dope positive charge nitrogen species on it. The sample was ded as KF-8ST10-8AN20-9.5HT30-8ST30 (8ST10; steam activation at 800 °C with 10 mL water, 8AN20; thermal CVD treatment at 800 °C charging 20 mL acetonitrile, 9.5HT30; annealing at 950 °C for 30 min, 8ST30; steam activation at 800 °C with 30 mL water), obtaining great nitrate adsorption capacity of 0.74 mmol/g in 200 mg/L nitrate solution at pH 3.0. For deeply exploring the adsorption characteristics of this well-modified ACFs, in this study, the pH of point of zero charge (pHpzc) for KF8ST10-8AN20-9.5HT30-8ST30 as well as KF1500 has been explored to further understand the surface charge properties. The results indicated that pHpzc was 7.2 for KF1500 and that for modified ACFs KF-8ST10-8AN20-9.5HT30-8ST30 was about pHpzc 7.0. Effect of solution pH at various initial solution concentrations was also studied, and adsorption isotherms were well fitted by Langmuir model at pH 1.5–8, and adsorption capacity obtained from the fitting was 0.67 mmol/g (R2 = 0.993). In addition, the effect of temperature (15–35 °C) on nitrate adsorption was also tested. Moreover, desorption of nitrate hydrochloric acid solution proceeded for 3 h at pH 3. With the above results, the working condition of quaternary nitrogen (N–Q) and carbon π bond was investigated, and the contribution to nitrate adsorption by N–Q was also defined more clearly which was 22% at least.

MEASUREMENT OF NITRATE ADSORPTION CAPACITIES WITH DIFFERENT SOILS – A COLUMN TRACER STUDY

MEASUREMENT OF NITRATE ADSORPTION CAPACITIES WITH DIFFERENT SOILS – A COLUMN TRACER STUDY

Synergistic effect of electrostatic adsorption and ion exchange for efficient removal of nitrate

A novel nitrate adsorption material of quaternized chitosan-zeolite/Fe3+/Mg2+-glutaraldehyde (QZG) beads were prepared for efficient removal of nitrate from aqueous solutions. Modification of chitosan by grafting glycidyl trimethyl ammonium chloride (GTMAC) onto the amino group. The coprecipitation method is used to combine the hydroxide and quaternary ammonium salt modified chitosan to provide more specific active sites and improve the adsorption characteristics of the material. SEM, FTIR, XPS, TGA have been evaluated the physicochemical properties of the material that Indicated that functionalized QZG is favorably synthesized. QZG exhibited exceptional nitrate adsorption capacity (62.23 mg g−1) and has fast adsorption and desorption ability that can reach equilibrium with 15 min. Here, 100% regeneration was achieved with desorption of 0.02 mol L−1 NaCl. After six cycles of regeneration, the adsorption capacity was maintained at approximately 96%. The average diameter of QZG was 1–2 mm, which is convenient for recycling. Furthermore, the pseudo-second-order and Langmuir isotherm models fit the experimental data more reasonably, suggesting the occurrence of the physical and chemical adsorption process. These results suggest that QZG adsorbent can be applied to nitrate-containing wastewater in nature.

Surface modified mechanism of activated carbon fibers by thermal chemical vapor deposition and nitrate adsorption characteristics in aqueous solution

In this study, commercial activated carbon fibers (ACFs) KF1500 was modified by thermal chemical vapor deposition (CVD) method using acetonitrile and steam to adsorb nitrate ions in aqueous solution. Physical properties and surface chemical characteristics of each modified ACF were examined to reveal the surface modification mechanism of modified ACFs. Adsorption kinetics and influence of solution pH were also examined to investigate the adsorption properties. The sample of KF-8ST10-8AN20-9.5HT30-8ST30 showed maximal nitrate adsorption capacity of 0.74 mmol/g at solution pH 3, and surface area was calculated to be 1358 m2/g and 1483 m2/g by Brunauer-Emmett-Teller (BET) method and subtracting pore effect (SPE) method using αs plots, respectively. By means of modification, the quaternary N (or graphitic N) (N–Q) configuration, which is a strong site to adsorb nitrate ion, represented nearly 5 times greater value than that of KF1500. The N–Q configuration reached up to 1.86% in total elemental composition from 0.4% of KF1500. The adsorptive kinetic data of KF-8ST10-8AN20-9.5HT30-8ST30 ACFs were highly well described with pseudo-second-order (R2 = 0.998) model. The adsorption capacity of nitrate decreased rapidly with the increase of the alkalinity in nitrate solution, which indicated that hydroxyl groups rather than nitrate ions in the aqueous solution were more attractive and competitive to the N-Q and other adsorptive sites on the surface of ACFs.

Biochar from microwave pyrolysis of rice husk for tertiary wastewater treatment and soil nourishment

Abstract The present study investigated the potential tertiary treatment of wastewater by adsorption using rice husk biochar (RHC) obtained from microwave pyrolysis of rice husk. Adsorption experiments with RHC indicated phosphate and nitrate adsorption of 65% and 75% respectively. The adsorption kinetics indicated pseudo-second-order adsorption model for adsorption of nutrients on biochar with an R2 value more than 0.98. In addition, the Langmuir-Freundlich isotherm was observed to represent the adsorption of phosphate on RHC, whereas adsorption data of nitrate depicted Langmuir isotherm followed by Temkin and Dubinin-Radushkevich isotherms. The maximum phosphate and nitrate adsorption capacity were 71 mg/kg and 497 mg/kg respectively using Langmuir isotherm model. The desorption study indicated a release of 96.6% and 44.4% of adsorbed phosphate and nitrate, respectively. Hence, from 1 kg of nutrient loaded RHC about 68 mg of phosphate and 220 mg of nitrate can be extracted for land application.

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).

CHARACTERIZATION AND ADSORPTION CAPACITY OF AMINE-SIO2 MATERIAL FOR NITRATE AND PHOSPHATE REMOVAL

Amine-SiO2 material was synthesized and applied as a novel adsorbent for nitrate and phosphate removal from aqueous solution. The characterization of Amine-SiO2 were done by using TGA, FTIR, BET, and SEM analyses. Results showed that Amine-SiO2 had higher nitrate and phosphate adsorption capacity of 1.14 and 4.16 times, respectively, than commercial anion exchange resin (Akualite A420). In addition, Amine-SiO2 also had good durability with stable performance after at least 10 regeneration times, indicating that this material is very promising for commercialization in the future as an adsorbent for water treatment.

Enhanced nitrate adsorption by using cetyltrimethylammonium chloride pre-loaded activated carbon

ABSTRACT This paper used cetyltrimethylammonium chloride (CTAC) pre-loaded activated carbon (AC) to research nitrate adsorption. Effects of various parameters such as AC types, AC dosage as well as initial pH were studied. The results indicated that the ACs modified by CTAC can get higher nitrate removal. Even pH is neutral and basic, an accepted removal about 2.5 mg/g can be observed. The more CTAC pre-loaded on the AC surface, the higher nitrate adsorption capacity can be obtained. pH is regarded as a key factor affecting interactions between adsorbent and adsorbate, and the results confirmed that the nitrate adsorption on modified AC decreases gradually with the growth of initial pH. Besides, the acidic pH condition is much favoured for adsorption while the results gained a nitrate adsorption about 4.28 mg/g at pH = 3 condition. Sorption mechanism of nitrate on CTAC modified AC was investigated through two kinetic modellings including pseudo-second-order and Weber and Morris intra-particle diffusion model. The results imply that the generalized kinetic models tally well with experimental data. Additionally, interference of co-existing anions is examined, and the results showed that higher co-anions concentration would bring a heavier depression of the nitrate uptake due to its competing for adsorption sites.

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.

Surfactant-modified MFI-type nanozeolites: Super-adsorbents for nitrate removal from contaminated water

Abstract Three surfactant-modified zeolites with high external surface areas and small crystal sizes were synthesized and modified for the nitrate removal from contaminated water. ZSM-5 nanocrystals (NC), nanosheets (NS) and nanosponges (NSp) were synthesized by different processes in order to obtain nanocrystals and hierarchized zeolites with extended external surfaces. In order to obtain an anion exchanger system: Surfactant-Modified Nanozeolites (SMZN), the as-synthesized zeolites were modified with a cationic surfactant (HDTMA+Br−: hexadecyltrimethylammonium bromide). MFI-type zeolites with low external surface area and large crystal size (ZSM-5 microcrystals) were synthesized and modified with the same cationic surfactant for comparison with the SMZN through nitrate removal. N2 adsorption/desorption, XRD, SEM, TEM, and TGA analyses were done on the raw and the calcined form of the synthesized zeolites in order to determine the textural and structural properties. For the three studied materials nitrate removal tests were carried out in a large initial nitrate concentration range [0.8–40.5] mmol.L−1. Nitrate isotherms fitted Langmuir isotherm model and the maximum removal capacities were found to be 810 (±50), 1941 (±100), 2125 (±100) mmol.Kg−1 for SMZNC, SMZNS, and SMZNSp, respectively. SMZNSp showed the highest nitrate adsorption capacities obtained till now with surfactant-modified zeolites (SMZ) materials. These systems were found to be ultra-fast adsorbent systems and the kinetics fitted the pseudo-second order model.

Characterization of functionalized chitosan-clinoptilolite nanocomposites for nitrate removal from aqueous media.

The nanochitosan/clinoptilolite (Nano-CS/Clino) composite, Nano-CS/Clino activated by hydrochloric acid (Nano-CS/Clino@H) and Nano-CS/Clino functionalization with pentaethylenehexamine (Nano-CS/Clino@PEHA) has been used to removal of nitrate ions from aqueous media. The textural properties of the Nano-CS/Clino nanocomposites were studied by various characterization techniques. The Nano-CS was synthesized by ionic gelation technique that using tripolyphosphate as cross-linking agent. The BET specific surface area of chitosan and Nano-CS is 0.9774 and 52.8850 m2/g. The effects of different parameters on the removal of nitrate were measured in detail. The prepared Nano-CS/Clino@PEHA composite possess enhanced nitrate adsorption capacity of 277.77 mg/g than Nano-CS/Clino@H and Nano-CS/Clino were found to be 227.27 and 185.18 mg/g. The Dubinin-Radushkevich, Freundlich and Langmuir adsorption models were applied to describe the equilibrium isotherms. The experimental data were also analyzed by first- and second-order and intra particle diffusion. Thermodynamic parameters studies revealed that the nature of adsorption nitrate by nanocomposites synthesized is spontaneous and exothermic. The overall adsorption tendency of synthesized nanocomposites toward nitrate (NO3-) in the presence of CO32-, SO42- and Cl- under competitive conditions, followed the order: NO3- > CO32-> Cl-> SO42-. Desorption process was carried out with NaOH and proven it was an effective agent in the discharge of nitrate.

Simultaneous removal of nitrate and phosphate from wastewater using solid waste from factory

Phosphorous and nitrogen concentration, respectively, between 20–100 and 500–1000 μg/L can cause eutrophication. Thus, developing efficient low-cost removal method is important to protect the aquatic environment. The aim of this study is to investigate simultaneous nitrate and phosphate adsorption capacity of solid waste residue (SWR) generated from Awash Melkassa Aluminium Sulphate and Sulphuric Acid Factory. Batch adsorption experiments were conducted to evaluate the effect of various parameters on the simultaneous removal of nitrate and phosphate ions. The experimental results show that the equilibrium time was attained within 90 min, while the optimum pH and adsorbent dose were found to be 7 and 20 g/L, respectively. The pseudo-second-order equation with R2 values 0.99 and 1, respectively, fits to the adsorption kinetics of nitrate and phosphate. Moreover, isotherm analysis shows that adsorption of nitrate and phosphate was better modeled with Freundlich and Langmuir isotherms with R2 0.99 and 0.98 for phosphate and 0.99 and 0.96 for nitrate, respectively. Results of regeneration of the spent adsorbent show nearly 50% of the adsorbed phosphate can be desorbed with NaOH, while that of nitrate is 99.75%. Under optimum conditions, SWR can potentially remove phosphate from wastewater. However, the adsorbent is not suitable to remove nitrate ion from wastewater.

Study on the influence of surface potential on the nitrate adsorption capacity of metal modified biochar.

Carbon materials, as effective adsorbents to numerous aqueous cationic contaminants, have been hardly applied to remove anions in wastewater. In this work, different modifying agents were used to modify corncob biochars (CC) and the surface potentials of these modified biochars were determined. Based on the findings, modification principle was determined to reveal the relationship between surface potentials of the biochars and their nitrate adsorption capacities. The surface potential was dominated by the metal cations and multivalent cations led to even positive zeta potential. The formation of metal oxide not only led to the augment in surface area but also increase the surface charge. FeCl3-modified biochar (Fe-CC) with the highest positive surface charge was utilized to remove anions (nitrate) from aqueous solutions. Characterization results confirm that Fe2O3 structure were successfully formed on biochar surface. This led to the formation of iron nitrate hydrate (Fe(NO3)3·9H2O), which enabled higher nitrate adsorption performance than that of pristine biochar. Batch experiments showed that nitrate adsorption on the Fe-CC was stable and almost independent of experimental pH and temperature. Based on the Langmuir model results, the maximum nitrate adsorption capacity of Fe-CC was 32.33mg/g. Coexisting anions had negative influence on the adsorption performance. Findings of this work suggest that the modified biochar can be used in wastewater treatment to remove anions such as nitrate. Graphic abstract ᅟ.

Removal of phosphate and nitrate ions from aqueous solution using La3+ incorporated chitosan biopolymeric matrix membrane

The present investigation was carried out for the removal of phosphate and nitrate ions from aqueous solution using lanthanum incorporated chitosan membrane (La@CS) prepared by casting method. Systematic adsorption studies were performed by varying the influencing parameters like contact time, dosage, pH, interfering anions and temperature were optimized for the maximum phosphate and nitrate adsorption capacities. The adsorption equilibrium process was examined by Freundlich, Langmuir and Dubinin-Radushkevich isotherm models. The La@CS membrane showed an adsorption capacity of 76.6 and 62.6 mg/g for phosphate and nitrate ions respectively. Thermodynamic parameters such as ∆G°, ∆H° and ∆S° were calculated to understand the nature of adsorption. The synthesized La@CS membrane was characterized by FTIR, SEM, EDAX with mapping analysis, XRD, AFM, TGA-DSC and zero point charge analysis. The possible adsorption mechanism was found to be electrostatic attraction as well as by ion exchange between La@CS membrane and both anions like phosphate and nitrate. The experimental results clearly indicated that the prepared La@CS membrane could be utilized for the removal of phosphate and nitrate ions from aqueous solution.

Triamine-bearing activated rice husk ash as an advanced functional material for nitrate removal from aqueous solution.

In this study, we proposed a simple method for preparing triamine-bearing activated rice husk ash material (TRI-ARHA) as an advanced functional material with high nitrate adsorption capacity and durability. The novel TRI-ARHA was generated via a post-synthesis grafting method and modified by acidification to form ammonium moiety. TRI-ARHA was then characterized by using thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy and SEM-mapping. The TRI-ARHA had high nitrate adsorption capacity of 163.4 mgNO3 -/g, which was 2.06 times higher than that of a commercial anion exchange resin (Akualite A420) due to strong interactions of Si, C, and N in the material structure. This functional material with good durability after 10 cycles could be very promising for adsorption of other anions (e.g. sulfate and phosphate) in water and wastewater treatment.