Nitrate removal using Purolite A520E ion exchange resin: batch and fixed-bed column adsorption modelling

Abstract

Removing excessive nitrate from water is essential because it causes eutrophication which in turn has a harmful effect on aquatic life, resulting in a reduction in biodiversity and posing a danger to people's health when the water is used for drinking. In this study, nitrate removal from aqueous solutions was studied using an ion exchange resin (Purolite A520E) in batch and fixed-bed column experiments. Batch adsorption kinetics was very well described by pseudo-first-order, pseudo-second-order and homogeneous surface diffusion models for resin doses 1.5 and 3.0 g/L at a nitrate concentration 20 mg N/L. Column kinetic data satisfactorily fitted to the empirical Thomas model and a numerical model based on advectiondispersion equation for filtration velocities 2.5 and 5.0 m/h at a column height of 12 cm and inlet concentration 20 mg N/L. The experimental and Thomas model predicted breakthrough adsorption capacity ranges for the two filtration rates were 12.0-13.5 and 8.2-9.7 mg N/g, respectively, whereas the maximum adsorption capacity determined using Langmuir adsorption isotherm model in the batch study was 32.2 mg N/g.

Avaliação do uso de argilas montmorilonitas modificadas na adsorção de nitrato em meio aquoso

“…Caracterização dos adsorventes (50 a 100 mg de massa seca em 40 mL de solução) são comparáveis àqueles obtidos por Nur et al (2015), os quais obtiveram remoções de 75 a 86% para concentrações de resina variando de 1,0 a 3,0 g L -1 .…”

“…As curvas cinéticas experimentais obtidas neste estudo, junto ao modelo de PSO ajustado a elas, estão apresentadas no diagrama da Figura 5.Os valores dos parâmetros dos modelos PPO e PSO ajustados aos dados experimentais, bem como os coeficientes de determinação e os desvios relativos médios para o ajuste, são mostrados na Tabela 1.Inicialmente, é possível afirmar, a partir dos dados cinéticos determinados, que, nas condições dos ensaios, o tempo de equilíbrio é atingido em aproximadamente 120 minutos, com percentuais de remoção de nitrato de 53 e 97% para a MAO e para a RAC, respectivamente Nur et al (2015). também observaram tempos de equilíbrio de 2 horas para a adsorção de nitrato na RAC, em condições próximas às aqui utilizadas.…”

Characteristics of Nitrate Removal from Aqueous Solution by Modified Steel Slag

“…In addition, metal ions such as calcium, iron and their metal oxides are hydrated on the surface of MSS to form hydroxides and hydrated metal oxides so that there are a large number of hydroxyl groups in a mutually associative or separate form present at the interface of the adsorbent, which has been confirmed in the infrared spectrum ( Figure 10). Thus, the nitrate may be adsorbed by ion exchange (Equation (10), Figure 11I) [22,29,51,52] or through hydrogen bonding (Equation (11), Figure 11II) [38] with the hydroxyl group.…”

“…Therefore, it is very important to select the appropriate nitrate adsorption material [8,9]. Many materials, such as activated carbon, sepiolite, chitosan and ion exchange resin [8,[10][11][12] can remove nitrate in water, but most of these compounds have high production costs, complex synthesis processes or are difficult to regenerate. Accordingly, they are not suitable for the treatment of large areas of nitrate-contaminated water.…”

EFFECT OF Cu-PUROLITE A400 RESIN ON ADSORPTION OF NITRATE AND NITRITE IN WASTEWATER TREATMENT

“…The adsorbents, which are also natural resins, applied by the research institute, are modified zeolites with the addition of H 2 SO 4 [15], amine group quartermodified chitosan beads [14] and alloy Zr(IV) with sugar beet pulp [16]. Synthetic resins used in nitrate and nitrite removal are strong base anion exchange resins with considerable adsorption capacity, such as ion-exchange resin Dowex 21K XLT with modified ferrous metals [17], Purolite A100 [18], Purolite A520E [19][20], A-250 IXR [21], Purolite A300 [20] and Indion NSSR [22].…”