Removal of nitrates from water by environmental waste materials (original) (raw)
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Efficacy of onion peel towards removal of nitrate from aqueous solution and field samples
Environmental Nanotechnology, Monitoring & Management, 2019
Present study highlighted on the efficacy of onion peel dust (OPD) towards removal of nitrate ions from aqueous solution. The experiment was confined on the effect of initial nitrate ion concentration, pH, adsorbent dose, contact time and temperature on the nitrate removal. The point of zero charge was recorded 6.344. The optimum pH for the maximum removal of nitrate was 12.0. The adsorption equilibrium data nicely fitted with Langmuir isotherm with very high goodness of fit (R 3 = 0.908). Study results revealed that OPD, a waste material, have good performance towards removal of nitrate ions from aqueous solutions. Kinetics of nitrate adsorption data clearly revealed that nitrate adsorption obeyed Intraparticle diffusion and Pseudo-first-order kinetics. The adsorbent surface morphology both before and after adsorption was assessed by Infrared spectral study. The maximum adsorption capacity of OPD was found to be 5.93 mg g −1 and maximum 85% nitrate removal from the field samples was achieved by OPD. The values of thermodynamic parameters ΔH°, ΔG°and ΔS°indicated that the nature of nitrate adsorption is dominated through endothermic, spontaneous and feasible. The exhausted OPD was regenerated by 0.1 M NaOH solution. Therefore, present study indicates that OPD could be an inexpensive material for removal of nitrate from aqueous medium and exhausted adsorbent can be easily regenerated.
Use of agricultural waste for the removal of nitrate-nitrogen from aqueous medium
Journal of Environmental Management, 2009
The effectiveness of wheat straw charcoal (WSC) and mustard straw charcoal (MSC) as adsorbents for the removal of nitrate-nitrogen from water has been investigated. Commercial activated carbon (CAC) was used as a standard for comparison. The adsorption effectiveness of MSC was highest followed by CAC and WSC irrespective of the concentration of nitrate-nitrogen in the range of 0e25 mg/l. The effects of temperature in the range of 15e28 C on adsorption by WSC and MSC have also been investigated. It was observed that the temperature dependence of the adsorption effectiveness of MSC was higher than that of WSC and CAC. It is concluded that the MSC can be used for the in situ treatment by adsorption of nitrate-nitrogen in underground and surface water.
The ability to convert a waste by-product, sunflower seed husk (Helianthus annuus), into an economically cheap adsorbent has been investigated for nitrate removal from aqueous solution through sorption studies. The sunflower seed husk was characterized by physisorption, Brunauer Emmet Teller (BET). Fourier transform Infrared (FTIR) were recorded before and after adsorption to explore the number and position of the functional groups available for nitrate binding on to the studied adsorbent. Optimum adsorption conditions for nitrate removal were determined as a function of pH, adsorbent dosage and contact time. The sorption capacity decreased with increasing sorbent dosage. The optimum contact time was 120 min, optimum biomass dose was 3.0 g and the optimum pH for nitrate removal was 2.0. The adsorption data conformed to both the Langmuir and the Freundlich isotherms but fitted best into the Langmuir model. The R 2 for Langmuir equation was 0.9940 and that for Freundlich was 0.8190. T...
2021
Only 2.5% of the world's water is fresh, despite the fact that water covers approximately 70% of the planet. This water is used for several recreational purposes and gets polluted by wastewater disposal directly into freshwater bodies. Effluents dispersed into water bodies could be from various sources like industries, households, and agricultural activities. These effluents comprise heavy metals and chemical wastes directly released into water bodies without treatment and could include major contaminants like nitrates, nitrites, ammonia and phosphates. The present study mainly focuses on removal of four significant pollutants from agriculture wastes, i.e., nitrates, nitrites, ammonia, and phosphates. These pollutants are removed using adsorbents via a process known as adsorption. Adsorbents used in the study are fish scales and neem leaves. Several studies have been carried out to measure the efficiency of adsorbents in the removal of contaminants. These studies include equilib...
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Background: The objective of this work was to propose the treatment of the wastewater from Laguna da Jansen using adsorptive processes of residues of pineapple crown and shrimp chitosan. Methods: Residual substrates were distributed in 11 Erlenmeyers, and 250 mL of residual pond water were added; the solution was incubated under agitation at the times and amounts established by the Experimental Design (DCCR). After this period, analyses of pH, electrical conductivity, turbidity, nitrate, and nitrite, morphological analyses by SEM, and structural analyses by FTIR and XRD were performed. Results: The FTIR and SEM results showed that the biomass presented active chemical groups and a morphology rich in pores. The experimental design showed that the substrate content was the variable that influenced the lagoon effluent treatments for both tested biomasses; however, when observing the specific values of the response variables, the vegetable adsorbent was more efficient with the condition...
Nitrate removal from aqueous solution by adsorption onto various materials
Journal of hazardous materials, 2004
In this study sepiolite, sepiolite activated by HCl, slag and powdered activated carbon were used as adsorbent with a particle size was between 71 and 80 m (200-170 mesh). NaNO 3 solution (100 mg/l) was used in batch adsorption experiments for nitrate removal. First kinetic studies were carried out and it was determined that slag was not effective for nitrate removal, then contact time, pH and adsorbent dosage effects on nitrate removal by adsorption were investigated using other adsorbents except slag. The equilibrium time was found to be 30, 45, 5 min for sepiolite, powdered activated carbon and activated sepiolite, respectively. The most effective pH value for nitrate removal was 2 for powdered activated carbon. pH value did not affect nitrate removal significantly for other adsorbents. Adsorbent dosages were varied from 5 to 20 g/l solutions. An increase in adsorbent dosage increased the percent removal of nitrate. A series of isotherm studies were undertaken and the data evaluated for compliance with the Langmuir and Freundlich isotherm models. To investigate the adsorption mechanisms, three simplified kinetic models, i.e., first-, second-order and intraparticle diffusion were tested. Adsorption followed second-order rate kinetics. The correlation coefficients for second order kinetic model are greater than 0.996. Experimental data show that sepiolite activated by HCl was effective for nitrate removal.
Olive Pomace as an Abundant, Low-cost Adsorbent for Nitrate Removal from Aqueous Solution
Many methods have been applied in order to reduce nitrate concentration in aqueous solutions, among them is the adsorption onto the surface of agricultural wastes. In this study, batch experiments were carried out to investigate the adsorption of nitrate onto olive pomace (OP), a solid by-product of olive oil industry. To achieve this, six parameters were studied by varying only one parameter at a time. These parameters were the effect of: pH, contact time, temperature, adsorbent weight, agitation speed and nitrate concentration. The optimum pH was found to be 5, while the optimum time was 75 minutes. Nitrate removal percentage was found to increase with increasing adsorbent weight or temperature, with 92.5% of nitrate removed by using 2 g of OP and 48% of nitrate was removed at 60ºC. Generally, agitation speed increased the nitrate removal percentage, while high initial concentration of nitrate was found to decrease its removal percentage. These findings, combined with the low cost of OP and its abundance, suggest that OP is a potential adsorbent for nitrate removal provided that the optimum conditions are applied. Applying this method for nitrate removal will make drinking water safer to drink and wastewater safer to discharge.
Orange Peel Wastes as Low-Cost Adsorbent for Removal of Nickel and Chromium in Aqueous Solution
Malaysian Journal of Catalysis
Agricultural-by products such as orange peel (OP) was found to be abundant in quantity and had great components to adsorb the heavy metals. In this study, orange peel was used as biosorbent in adsorption process of heavy metal. The main aim of this study was carried out to examine the ability of adsorbents orange peel to remove nickel, Ni(II) and chromium, Cr(VI) ions from aqueous solution. From literature review, orange peel was proven can adsorb considerable quantities of Ni(II) and Cr(VI) ions in aqueous solution. The adsorption of Ni(II) and Cr(VI) ions were conducted in batch experiment to investigate the different parameters which are the effect of contact time, pH, adsorbent dosage and initial Ni(II) and Cr(VI) concentration. the optimum conditions for Cr(VI) were achieved when using 1.5 g of acid-treated orange peel at pH 3 in 20 ppm of initial Cr(VI) concentration which successfully removed 47.45% of Cr(VI) from aqueous solution within 90 min of contact time. The optimum co...
Submerged membrane adsorption hybrid system using four adsorbents to remove nitrate from water
Environmental Science and Pollution Research, 2017
Nitrate contamination of ground and surface waters causes environmental pollution and human health problems in many parts of the world. This study tests the nitrate removal efficiencies of two ion exchange resins (Dowex 21k XLT and iron modified Dowex 21k XLT (Dowex-Fe)), and two chemically modified bio-adsorbents (amine grafted corn cob (AG corn cob) and amine grafted coconut copra (AG coconut copra)) using a dynamic adsorption treatment system. A submerged membrane (microfiltration) adsorption hybrid system (SMAHS) was used for the continuous removal of nitrate with a minimal amount of adsorbents. The efficiency of membrane filtration flux and replacement rate of adsorbent were studied to determine suitable operating conditions to maintain the effluent nitrate concentration below the WHO drinking standard limit of 11.3 mg N/L. The volume of water treated and the amount of nitrate adsorbed per gram of adsorbent for all four flux tested were in the order Dowex-Fe > Dowex > AG coconut copra > AG corn cob. The volumes of water treated (L/g adsorbent) were 0.91 and 1.85 and the amount of nitrate removed (mg N/g adsorbent) were 9.8 and 22.2 for AG corn cob and Dowex-Fe, respectively at a flux of 15 L/m 2 h.