KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 https://bestjournal.
id/index.
php/kovalen Effect of Column Diameter on the Performance of an Ion Exchange System in Reducing Water Hardness Widya Yeni Rawati1A.
Sunardi2 .
Sri Widarti3.
Sumarja4.
Muhammad Nur Alim4 .
Jurusan Teknik Konversi Energi.
Politeknik Negeri Bandung.
West Java.
Indonesia .
Jurusan Teknik Refrigerasi dan Tata Udara.
Politeknik Negeri Bandung.
West Java.
Indonesia .
Jurusan Teknik Konversi Energi.
Politeknik Negeri Bandung.
West Java.
Indonesia .
Jurusan Teknik Kimia.
Politeknik Negeri Bandung.
West Java.
Indonesia Abstract.
Ion exchange is an effective method for removing hardness ions such as Ca and MgAA from water, and its performance is strongly influenced by column design parameters.
This study aims to evaluate the effect of column diameter on the efficiency of a sequentially operated cationAeanion ion exchange system at a constant flow rate of 10 L/h.
Six column diameters .
, 25, 30, 35, 40, and 50 m.
were tested using synthetic solutions.
The results showed that the 30 mm column achieved the highest ion-exchange performance, with a removal efficiency This column also produced the most well-defined breakthrough curve, yielding an exchange capacity 76 mg/g, equivalent to 0.
437 meq/g for Ca and 0.
720 meq/g for MgAA.
These findings indicate that the 30 mm diameter provides an optimal balance between contact time and flow distribution, resulting in superior ion exchange Keywords: ion exchange, column diameter, column efficiency.
Ca.
MgAA Abstrak.
Pertukaran ion merupakan metode yang efektif untuk menghilangkan ion penyebab kesadahan seperti Ca dan MgAA dari air, dan kinerjanya sangat dipengaruhi oleh parameter desain kolom.
Penelitian ini bertujuan untuk mengevaluasi pengaruh diameter kolom terhadap efisiensi sistem pertukaran ion kationAeanion yang dioperasikan secara berurutan pada laju alir konstan sebesar 10 L/jam.
Enam variasi diameter kolom .
, 25, 30, 35, 40, dan 50 m.
diuji menggunakan larutan sintetis.
Hasil penelitian menunjukkan bahwa kolom berdiameter 30 mm memberikan kinerja pertukaran ion tertinggi dengan efisiensi penyisihan sebesar 92,47%.
Kolom ini juga menghasilkan kurva breakthrough yang paling jelas, dengan kapasitas pertukaran sebesar 8,76 mg/g, yang setara dengan 0,437 meq/g untuk Ca dan 0,720 meq/g untuk MgAA.
Hasil ini menunjukkan bahwa diameter kolom 30 mm memberikan keseimbangan optimal antara waktu kontak dan distribusi aliran, sehingga menghasilkan efisiensi pertukaran ion yang lebih baik.
Kata kunci: pertukaran ion, diameter kolom, efisiensi kolom.
Ca.
MgAA Received: November 14, 2025.
Accepted: January 5, 2026 Citation: Rawati.
Sunardi.
Widarti.
Sumarja.
, and Alim.
Effect of Column Diameter on the Performance of an Ion Exchange System in Reducing Water Hardness.
KOVALEN: Jurnal Riset Kimia, 11.
: 81-93.
INTRODUCTION
and steam generation (Widarti, 2.
The Water is an essential natural resource for quality of water used in these processes is both domestic and industrial activities (Achmad highly important to ensure operational stability.
Fauzi et al.
, 2.
In industrial settings, it is One important indicator of water quality is its commonly used for cleaning, heating, cooling, hardness level (Sahidin et al.
, 2.
, which is mainly associated with the presence of calcium Corresponding Author E-mail: widya.
yeni@polban.
and magnesium ions.
These ions occur https://doi.
org/10.
22487/kovalen.
2477-5398/ A 2025 Rawati et al.
This is an open-access article under the CC BY-SA license.
KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
naturally in water bodies as a result of that at an optimum flow rate of 0.
6 GPM, a geological interactions with mineral-bearing hardness reduction efficiency of up to 100% Globally, hardness is a widespread was achieved, with saturation times of 168 issue, with more than 85% of freshwater minutes for the cation resin and 46.
4 minutes sources classified as hard water (Yu et al.
for the anion resin.
This study emphasizes that These ions tend to form insoluble operational parameters, particularly flow rate, deposits such as calcium carbonate and play a crucial role in determining the ion magnesium carbonate (Gao et al.
, 2.
, which exchange capacity of the resin and the overall can accumulate in pipelines and equipment, performance of the system.
causing scale formation (Maulizar et al.
, 2.
Another study conducted at flow rates Such scaling reduces the effectiveness of ranging from 2.
90Ae4.
33 mL/s .
44Ae15.
59 L/.
industrial systems that rely on heat transfer.
and resin bed heights of 14 and 17 cm showed Over that the optimal condition was achieved at a efficiency (Xing et al.
, 2.
, leading to flow rate of 4.
33 mL/s with a column height of increased energy consumption and higher 14 cm, resulting in a hardness reduction operational and maintenance costs.
Therefore, efficiency of up to 93.
56% (Nuryoto et al.
managing water hardness is essential to Research on the effect of resin bed maintain equipment performance and reduce height has also been reported.
Panjaitan operational losses.
(Panjaitan et al.
, 2.
demonstrated that using Several treatment technologies have been a resin bed height of 20 cm and an optimum developed to reduce water hardness, such as flow rate of 50 mL/min in the treatment of chemical precipitation, membrane filtration, and chromium-containing wastewater resulted in a ion exchange (Xing et al.
, 2.
Among these removal efficiency of 97.
methods, ion exchange is widely regarded as Although many studies have examined one of the most effective approaches for variations in flow rate and ion exchange column removing hardness ions.
This process involves cross-linked, insoluble polymer resins that dimensionsAiparticularly column diameterAi facilitate a stoichiometric exchange between has received relatively little attention.
Column ions in the solution and those attached to the diameter affects the linear flow velocity (Fekete resin matrix (Ahmer & Uddin, 2.
Because et al.
, 2.
, residence time (Syeda et al.
the resins can be regenerated and reused, ion 2.
, and ion exchange efficiency (Rodrigues exchange offers good efficiency and long-term Reis & Hu, 2.
Differences in diameter also economic benefits, making it suitable for continuous industrial applications.
distribution within the resin bed (Quinn, 2.
The development of an ion exchange column system has been carried out by Kusumawati (Kusumawati et al.
, 2.
, in MATERIALS AND METHODS Materials which the ion exchange system was modified The resins used consisted of the cation by adding an activated carbon column after the exchange resin Trilite KC-08 and the anion cation and anion resins.
The results showed exchange resin Trilite MA-12.
The synthetic KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
hard water sample was prepared using In the design of the ion exchange system, a technical-grade CaClCC and MgClCC, while 0.
dosing pump is used to maintain a stable flow EDTA (Merc.
was used as the titrant solution.
rate (Marin et al.
, 2.
, which is monitored For the regeneration process, 1 M NaOH and 1 using a flowmeter.
Each column is constructed M HCl (Merc.
were employed.
from acrylic tubing due to its high transparency, lightweight properties, and ease of modification Apparatus Design for various fittings and connections (Zaokari et The system consists of two resin columns , 2.
arranged in series, namely a cation column The column diameter variations used were followed by an anion column.
Figure 1 presents 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, and 45 a simple illustration of the ion exchange mm, with a total column length of 30 cm and a mechanism based on the experimental setup fixed resin bed height of 15 cm.
The bottom used in this study.
section of each column was equipped with a mesh layer to prevent resin leakage.
The piping system was fitted with control valves to regulate flow rate and direction, and flexible tubing was used as connectors between components.
The entire unit was mounted on a PVC base supported by a hollow steel frame to ensure stability, ergonomic operation, and ease of Figure 1.
Simple illustration of exchange mechanism relocation during laboratory use (Figures 2 and Cation Regenerant Tank
Anion Regenerant Tank
Cation Exchange Column
Anion Exchange Column
Flow meter
Pump
V10
V11
V12
V13
Feed Water Tank Regeneration Waste Outlet Effluent Tank Figure 2.
Ion exchange column system design KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
Figure 3.
Ion exchange apparatus Instrumentation then soaked in 1 N HCl or 1 N NaOH solution.
The supporting equipment used included a respectively, for 1 hour for activation (Broovy digital conductivity meter (Hanna HI9813-.
, an et al.
, 2.
The resins were subsequently analytical balance (Kern ABS 220-.
, and rinsed with distilled water until a neutral pH was standard glassware for sample collection and Afterward, the resins were packed hardness titration.
into their respective columns, followed by a backwashing step (Shahab & Setiorini, 2.
Procedure in which water flows from the bottom to the top Sample preparation The artificial water sample was prepared by dissolving MgClCC and CaClCC in 40 liters of tap (Figure .
to ensure complete resin wetting and Channeling phenomenon where the feed solution forms Ion exchange apparatus preparation contact between the feed and the entire resin The resins were prepared by weighing the bed (Koch et al.
, 2.
cation and anion exchange resins, which were Cation Regenerant Tank
Cation Regenerant Tank
Anion Regenerant Tank
Anion Regenerant Tank
Cation Exchange Column
Anion Exchange Column
Flow meter
Flow meter
Pump
Anion Exchange Column
Cation Exchange Column
V10
V11
V12
V13
Feed Water Tank
Pump
V10
V11
V12
V13
Feed Water Tank Regeneration Waste Outlet Regeneration Waste Outlet Effluent Tank Effluent Tank Figure 4.
Schematic of cation backwash .
and anion backwash .
KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
Water treatment process moving from bottom to top, where anions such The water treatment sequence, or service as ClA and SOCEAA are exchanged with OHA ions flow, as shown in Figure 5, begins with the feed provided by the anion resin.
The treated water tank, from which water is pumped toward the then exits through the outlet into the effluent The water then enters the cation Through this ion exchange mechanism, column, flowing from top to bottom.
In this the concentrations of both cations and anions in column.
Ca and MgAA ions are exchanged with the water are significantly reduced, resulting in HA ions released by the cation resin.
The water improved water quality compared to the original subsequently flows into the anion column, feed water.
Cation Regenerant Tank
Anion Regenerant Tank
Cation Exchange Column
Anion Exchange Column
Flow meter
V10
V12
V13
V11
Pump Feed Water Tank Regeneration Waste Outlet Effluent Tank Figure 5.
Schematic of the water treatment flow
Cation Regenerant Tank
Anion Regenerant Tank
Cation Exchange Column
Anion Exchange Column
Flow meter
Pump
V10
V11
V12
V13
Feed Water Tank Regeneration Waste Outlet Effluent Tank Figure 6.
Schematic of the cation regeneration flow .
and anion regeneration flow .
KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
After the water treatment process, the resin valid and accurately reflects the effect of becomes saturated and loses its optimal ion exchange capacity.
To restore the resin capacity, a regeneration step is carried out The amount of cation and anion resin in each (Chandrasekara & Pashley, 2.
, in which the column was determined based on the effective resin is washed with a regenerant solution so column volume, calculated using the cylindrical that it returns to its active form and can be volume equation.
The mass of the resin was The regeneration scheme is shown in obtained by multiplying the resin volume by its Figure 6.
density, with the cation resin density being 1.
(Chromatographyonline, g/mL (Trilite KC-08, 2.
and the anion resin
RESULT AND DISCUSSION
Resin Efficiency Measurement density being 1.
09 g/mL (Trilite MA-12, n.
Conductivity Effluent samples were collected every 200 mL up to a total volume of 4 L to measure To examine the effect of column diameter, conductivity and hardness concentration using the resin bed height was kept constant.
This arrangement was intended to maintain a (Kusumawati et al.
, 2.
The experimental consistent mass transfer zone and contact data obtained are presented in Table 1.
time, ensuring that any observed differences Table 1 shows the changes in hardness were solely due to variations in column and conductivity after the ion exchange process diameter (Gebauer et al.
, 2.
By maintaining at various column diameters.
In general, the same resin bed height, the influence of increasing the column diameter results in other factors such as adsorption capacity and greater reductions in both hardness and Consequently, the comparison becomes more achieved at a diameter of 30 mm.
Table 1.
Effect of column diameter on hardness removal and conductivity Initial Hardness .
g/L as CaCOCE) Average Hardness .
g/L as CaCOCE) Column Diameter .
Efficiency (%) Initial Conductivity .
S/c.
Final Conductivity .
S/c.
Figure 7 presents the hardness reduction hardness at low effluent volumes (<0.
5 L),
efficiency curves for the different column followed by stabilization in the range of 10Ae30 It can be observed that all column mg/L up to 4 L of effluent.
This indicates that the diameter variations show a sharp decrease in resin had not yet reached its saturation point KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
reakthrough poin.
The column with a hardness value.
In contrast, smaller diameters, such as 20 mm, showed poorer stability, mm exhibited the best performance, characterized by the fastest suggesting non-uniform flow distribution.
decrease in hardness and the lowest stable Figure 7.
Curve of hardness as a function of effluent volume Figure 8.
Relationship between effluent conductivity and effluent volume The reduction in hardness in the effluent is emphasized that hardness removal efficiency is attributed to the ion exchange process between strongly influenced by column characteristics, the Ca and MgAA ions responsible for including diameter and resin volume.
hardness and the HA or NaA ions on the ion To observe changes in water quality based exchange resin.
A similar phenomenon was on another parameter, the conductivity versus reported by Li et al.
, who demonstrated effluent volume curve is shown in Figure 8.
The that the ion exchange process effectively decrease in effluent conductivity indicates a reduces water hardness by removing calcium reduction in the total dissolved ions due to the and magnesium ions.
A more recent study by ion exchange process occurring in the resin.
Gholami et al.
(Nasrollahi et al.
, 2.
also This phenomenon is consistent with the KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
findings of Petrov et al.
, who explained exchange process.
As a result, the overall ion that solution conductivity decreases as charged ions are removed through ion exchange in conductivity values similar to those in the 20 cation and anion resins.
mm column.
The 30 mm diameter column exhibited the As previously discussed, the hardness most significant decrease in conductivity, from removal values 6 mS/cm to below 0.
1 mS/cm at a volume of 4 L, because its diameter creates indicating that all columns were generally optimal hydraulic conditions for ion exchange.
At this diameter, the linear flow rate is concentrations to a similar extent.
In contrast, sufficiently low to allow adequate contact time the conductivity values demonstrated clearer between the solution and the resin, while the differences, which more accurately reflect the flow pattern remains uniform across the bed.
This combination minimizes mass-transfer sensitive to residual ions in the effluent.
The 25 mm diameter column also including ions that are not classified as hardness but still contribute to the total ionic conductivity, although not as substantial as that Therefore, focusing on conductivity of the 30 mm column.
Meanwhile, the 35 mm allows a better assessment of how column and 40 mm diameter columns experienced only diameter influences mass transfer, contact moderate reductions.
time, and flow uniformity.
Columns with The for the different column Ca Conductivity MgAA observed in the 20 mm and 50 mm column reduced contact time due to high linear diameters can be attributed to two key velocities or exhibit channeling, both of which phenomena: rapid flow rate and channeling.
result in higher conductivity despite similar In the 20 mm column, the small cross-sectional This area results in a higher linear velocity at the same volumetric flow rate.
This rapid flow performance indicator than hardness alone in reduces the contact time between the solution this system.
and the resin, causing insufficient ion exchange Based on the hardness removal results and leading to higher effluent conductivity.
discussed earlier, treatment efficiency was Conversely, in the 50 mm column, the larger performance of each column diameter.
non-uniform This condition often leads to channeling, where the solution preferentially effectiveness in reducing ion concentrations, treatment efficiency was calculated based on resistance instead of being evenly dispersed ion concentrations before and after the ion across the resin bed.
Channeling reduces exchange process.
The efficiency data in Table effective resin utilization because a portion of 1 were calculated using Equation .
(Nuryoto the resin does not actively participate in the et al.
, 2.
KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
yayceyceycnycaycnyceycuycayc (%) = The efficiency values for each column diameter ya0 Oe yayce ycu 100 ya0 variation are shown in Figure 9.
Figure 9.
Hardness removal efficiency as a function of column diameter Figure 10.
Breakthrough curve at 30 mm diameter Breakthrough Curve and Resin Capacity determined at C/CCA = 0.
05, in accordance with Since the effluent volume in this experiment common criteria in ion exchange studies (Lima was limited to only 4 L, the resin saturation et al.
, 2.
Theoretically, a breakthrough phenomenon .
could not be curve exhibits a sigmoidal (S-shape.
form that indicates three main zones: the unsaturated comprehensive breakthrough profile, a follow- zone, the mass transfer zone, and the saturated up experiment was performed using the 30 mm zone (Dima et al.
, 2.
However, in this diameter column with a more concentrated experiment, the resulting curve does not fully sample solution, namely 700 mg/L.
form an ideal S-shape.
This condition is likely The curve in Figure 10 shows that the C/CCA effluent volume, and the breakthrough point is caused by flow non-uniformity during the initial operation of the column, and the system not yet reached complete saturation.
KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
Table 2.
Ion exchange capacity of the resin in the 30 mm diameter column Q Ca2 Q Mg2 .
Volume (L) C .
g/L) C0 .
g/L) (C0-C) x iV Q mg/g The ion exchange capacity (Q) of the resin in condition suggests that the ion exchange the 30 mm diameter column is calculated using process occurred mainly within a limited portion Equation .
(He et al.
, 2.
of the mass transfer zone, meaning not all layers of the resin participated optimally.
It can also be influenced by the initial ionic form of the where CCA and C are the initial concentration and the effluent concentration .
g/L), respectively.
V is the effluent volume (L), and m is the mass of the resin .
The value of Q represents the amount of ions exchanged per unit mass of resin.
Based on Table 2, the ion exchange capacity of the resin increases with increasing effluent volume, approaching the saturation point at around 2 L.
The total resin capacity obtained is 8.
76 mg/g, which is equivalent to 0.
437 meq/g for Ca ions and 720 meq/g for MgAA ions.
According to the Samyang Corporation, the cation resin Trilite KC-08 has a total capacity of 1.
9Ae2.
1 meq/mL, while the anion resin Trilite MA-12 has a total capacity of 3Ae1.
4 meq/mL.
The capacity values obtained in this study .
437Ae0.
720 meq/.
indicate that the utilization of active sites in the resin has only reached approximately 9Ae15% of the total capacity.
This resin (NaA or HA) and the regeneration conditions, which significantly affect the resinAos ability to exchange Ca and MgAA ions.
Flow distribution in the column, variations in column diameter, bed porosity, and flow rate can cause uneven flow .
, which shortens the contact time between ions and the active sites of the resin.
Competition between Ca and MgAA ions in the solution also plays a role, as both ions compete for the same sites on the resin surface.
This is consistent with the findings of Mountadar (Mountadar et al.
, 2.
, who reported that the Duolite C206A resin has a maximum exchange capacity of approximately 20Ae30 mg/g for Ca and MgAA.
however, the actual capacity in a dynamic column system is much lower due to limitations in diffusion and flow distribution.
Overall, the results of this study indicate that the cationAeanion ion exchange column KOVALEN: Jurnal Riset Kimia, 11.
, 2025: 81-93 Rawati et al.
system performs reasonably well, but there remains potential for further optimization of operational conditions, such as flow rate, regenerant concentration, or column length, in performance of the resin media.
CONCLUSION
This study demonstrates that variations in column diameter have a significant effect on the efficiency of the ion exchange process in the ion exchange system.
Among the five variations tested, the column with a diameter of 30 mm achieving an efficiency of 92.
In this column, a clear breakthrough curve was observed, with an ion exchange capacity of 76 mg/g, which is equivalent to 0.
437 meq/g for Ca ions and 0.
720 meq/g for MgAA ions.
ACKNOWLEDGMENT
The authors gratefully acknowledge the Sistem Informasi Manajemen Penelitian dan Pengabdian Pada Masyarakat (SIPPM) POLBAN and the contributions of fellow researchers during the data collection and analysis stages of this study.
REFERENCES