Development of a High Performance Arsenic Adsorbent and Use for the Adsorbent
Kenichi MIYANISHI1, Tsutomu FUJIWARA1, Ai KUCHIBUNE1 and ShiroTAKADA.1
ASTEC Co.,Ltd 107-4 Iwabana-cho Himeji-City Hyogo 670-0028 Japan e-mail: miyanishi@astec-geo.co.jp

Abstract
In volcanic country Japan, in which exceed the environmental quality standard of arsenic in a drinking water.
Moreover, removal of arsenic in hot spring drainage is also a big subject of future. Now, arsenic removal
techniques are the hydroxide coagulation method use iron and aluminum etc. By this method, if a lot of drainage
is treated, treating of the sludge generated in large quantities will become a problem. Moreover, operation
management is troublesome and the problem that installation area is large. Then, it is cheap, and handling is easy,
and it looks forward to the effective arsenic removing methods don’t take installation area.
In this study, the adsorbent was put in the column, arsenic content imitation water was poured in it from theupper part, and flowed out from the rower part, treated water was water sampling, and arsenic concentration was
analyzed. The optimal absorbent was chosen from the result, it investigated about the influence which raw water
quality, treating conditions, etc. have on absorbent, and the validity as arsenic adsorption removing method was
examined.
The arsenic absorption ability is 5mg/l, and it is always possible for stable processing, and long-term driving ispossible. In addition, pH adjustment is uselessness or need, but there may be a little quantity of medicine use
because a range of reasonable pH value is wide. We establish a manufacturing process of production in large
quantities in future and develop higher-performance arsenic absorption materials
Key Words: Arsenic removal technique, adsorbent

Introduction
Arsenic is an industrially important chemical in semiconductor industry. On the other hand, it is a substance with ahigh risk in human health. Arsenic is designated as the poison by Poisonous and Deleterious Substances
Control Law as well as designated as detriment by applicable laws and regulations such as the water quality andwaste. In the chemical form of arsenic, the toxicity of inorganic arsenics such as As2O34 - and AsO43 – isextremely high compared with organic arsenic. The tap water standard to the arsenic provided by Act ofParliament is 0.01mg/l or less. The effluent standard of Water Pollution Control Law to the arsenic provided by Act
of Parliament is 0.1mg/l or less. The soil and water pollution with arsenic are serious social issue in Asian nations.
On an international basis, the water quality guideline value concerning arsenic is severe. The technologies tocompletely solve the problems as follow: ensuring safe water meeting the water quality criterion, development of
the treatment technology and the adsorbent of the generation sludge to prevent cross-contamination, themedicine remaining in the drinking water that originates in the adsorbent, are urgent needs.
The arsenic pollution ground in Asia extends to a large area such as Japan, China, Taiwan, Philippines, Thailand,
India, Bangladesh, Vietnam, Myanmar, Nepal, and Pakistan according to the material of NPO Asian Arsenic
Network. Especially, in Bangladesh, hundreds of people are reported to drink highly density (0.05-number mg/l)
contaminated groundwater. The polluters are mine operation, arsenic content coal combustion, geothermal power
stations, abandoned chemical weapons, contaminated wells, and polluted groundwater. Also there are pollution
by the natural phenomenon and pollution that originates in life and the productive activity. Particularly, the water
resource pollution by the elution of a stratum and soil inside arsenic becomes serious as the soil and theunderground water survey in each country of Asia proceed People are expecting the development of an effective,
economical cleanup technology. What is the urgent need is to obtain the technologies to completely solve theproblems as follow: ensuring safe water meeting the water quality criterion, development of the treatment
technology and the adsorbent of the generation sludge to prevent cross-contamination, the medicine remaining in-1-

the drinking water that originates in the adsorbent. In the report, the treatment technology of the arsenic polluted
water is described.
The method for removing arsenic for industrial use is cohesion and coprecipitation method, that uses the ironsalt and the aluminum salt. However, this method cannot be used in the place without electricity and thetechnology such as Bangladesh. Moreover, there are a lot of places where underground water is used as tap
water by the drop shipment when the well is used in Japan. We developed the efficient arsenic adsorbent used insuch a place. We report on the result of examining the arsenic adsorption characteristic and the use.

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Development of arsenic adsorbent
arsenic adsorbent
There is a report that ferrioxide covered sand was used as filter media toremoval arsenic effectively. However, the process of baking the ferrioxideon sand surface is necessary to manufacture this sand, but the process iscomplex and is high in cost. Therefore, it doesn't expand on a large scale.
The base material of this adsorbent, that had been developed this time, isporous and is coated iron and the oxide of aluminum. There is no complex
process like baking, and the process of manufacture is also easily. The
characteristic of this adsorbent is shown in Table.1.
Fig.1 Adsorbent of Arsenic (MP-C)
Table1.Characteristic of Absorbent

saturated hydraulic6.6×10-2cm/sec

conductivity
apparent specific gravity
absolute specific gravity
specific surface area
porositygrain diameter

0.759
1.508
2.077
960m2/g
0.50
0.46〜2.2mm︵％︶
Particle size

high specific gravity-3-particle size (mm)measured figure

2.2 以上1.71-2.2
1.17-1.71
0.78-1.17
0.46-0.78
0.46 or less

0.0
0.1
32.8
47.4
18.5
1.2

Fundamental Experiment

A mount of A bs orbed ( mg /g ) /Concentra ti on of A l a nd F e ( ppm)

Confirmation of proper pH
Simulated water (AS (Ⅲ) ・ As(V)each
420mg-As/L) was adjusted by sulfuric acid and3.5
sodium hydroxide to PH2〜12. The batch-wise3
As(Ⅲ)
adsorption examination was carried out. Fig.2
As(Ⅴ)
2.5
Al
shows the result.
Fe
2
Both As (Ⅲ) and As (Ⅴ) have the arsenic
1.5
adsorption ability in the range of about pH4-9
1
according to Fig.2. However, the amount of
0.5
adsorption of arsenic decreases when
0
1
3
5
7
9
11
becoming a strong alkaline. As one can see thepHfollowing reactive type, when the pH is acidity,
the plus is electrified on the surface of theadsorbent. On the other hand, when pH is
Fig.2 Amount of As Absorbed depend on Form of As and pH
alkalinity the minus is electrified on it. Therefore,
arsenic adsorbs depending upon the pH.
+H++OHMoreover, the adsorption ability of As (Ⅲ) cannot be seen
Fe-OH2+Fe-OH
Fe-Owhen becoming a strong acid, and the elution of iron and thealuminum ion happens. Therefore, it can be said that a proper
pH of the arsenic removal is the vicinity of the neutral.
As for the mechanism of arsenic eluting from the iron hydroxide colloid, by contacting with the high pH water,
the charge state of iron colloid changes and arsenic desorbs. For this reason, after this adsorbent reaches
saturation, arsenic can be desorbed by alkaline water, and recycling is possible.

As(Ⅲ): q = 1.588 × C
As( )： q = 1.34 × C

As(Ⅲ）
As(Ⅴ))
Freundlich(As(Ⅲ) )Freundlich (As(Ⅴ)

10

E qui l i bri um A mount of A ds orbed ( m g /g )Equilibrium adsorption test
To evaluate the arsenic adsorption ability of theadsorbent, batch-wise equilibrium adsorption test
was run. Simulated water (AS (Ⅲ) ・As(V)each
20mg-As/L) was adjusted to pH7 and the amount ofadsorbent was changed and tested. The result isshown in Fig.3. The approximate formula isdescribed in parallel in case of assuming that theactual measurement value is followed Equilibrium
Adsorbed Isotherm of Freundlich.

As(Ⅲ)：y = 1.5881x
2
R = 0.8961

As(Ⅴ)：y = 1.3409x2
R = 0.9539

1
0.1

1

10

Equi l i bri um Concentra ti on ( ppm)

0.439

0.51

Fig.3 Equilibrium Adsorbed Isotherm

q：equilibrium adsorption amount (mg/g)
C：equilibrium concentration (mg/l)
There is little difference for the removal of As ( ) and As ( ) ; so that a high adsorption ability in a wide density
range can be expected.

-4-0.43880.51

Table2. Amount of As Absorbed depend on As Concentration
As Concentration (mg/l)
Amountof

As Adsorbed

As( )
As( )

0.1
0.58
0.41

0.5
1.17
0.94

1.0
1.59
1.34

5.0
3.22
3.04

10.0
4.36
4.34

20.0
5.92
6.17

Experimental conditions
Raw water density: 5.00mg/l
Raw water pH:6.78
Adsorbent volume:159.20cm3
Adsorbent weight: 93.0g
SV:5h-1(796ml/h)

As
(Ⅴ
As
)+
F(Ⅴ
)+
B(
OH
)3
As
(Ⅴ
)+
PO
43
As
(Ⅴ
)+
SO
42
As
(Ⅴ
)+
Cl
As
(Ⅴ
)+
HC
O3
As
(Ⅴ
)+
NO
3-

0.140

As Concentration (ppm)

Continuous passing water experiment
A special adsorbent was filled in the column,
and the simulative water adjusted to As 5mg/L (Ⅴ)
was passed to the column continuously in the
direction of a downward style with a micro tube
pump.

As
(Ⅴ
)

Amount of Adsorbed (mg/g)

Influence of coexistence negative ion
The coexistence material that adsorbs the adsorbent
3.5
3
has the possibility of influencing the arsenic adsorption.
2.5
2
1.5
To become 100mg/l, other negative ions (PO43-､F-､
1
0.5
B(OH)3-､SO42-､Cl-､HCO3-､NO3-) were added to As
020mg-As/L (Ⅴ) solution. The batch-wise adsorption test
was carried out.
According to Fig.4, an adsorbent rank of the negative ion
Coexistence
Ion
Fig.4 Influenceof Coexistence
Ion
in
the
adsorbent
used
this
time
is
As>PO43->NO3->CO32->SO42->Cl .
It is unconfirmed how much affect PO43 give.
However, the adsorption ability decreases only by about 30% though five times the coexistence material areadded compared with arsenic.
Therefore, the coexistence material of the low concentration will be almost unaffected.

0.120
0.100
0.080
0.060
0.040
0.020
0.000
0

12

24

36

48

60

72

84

96

108

120

Total Flow (L)Fig.5 Breakthrough Curve

According to Fig.5, when the tap water standard is assumed to be a breakthrough point,
the amount to the breakthrough of the arsenic theory adsorption is 5.13mg/g.
The densities of the treat water can be processed up to 0.001(detection limit) . It is possible to use it safely as adrinking water. If the arsenic density of processing water is 0.5mg/l, and the amount of processing is 1m3/h(SV:1),
it takes the breakthrough adsorbent for about seven months. Therefore, this amount of adsorption can be called
as a great outcome in the economical efficiency and automatic running perfomance as a disposable adsorbet.

-5-Experiment that uses discharged water
Experiment 1
The density of arsenic was detected from the water obtained from the waterway in Takachiho-cho of
Miyazaki Prefecture. Then, the column experiment was done by using MP-C.
Raw water properties
The raw water properties are shown in Table.3.
Table.3 Characteristic of raw water

Concentration(simple analysis)
6.9
0.02mg/l
0.2mg/l
0.05mg/l

pH
As
PO43FeBench-scale column testing
In the column examination, the plastic column filter of 16mm in
the diameter and 165mm in length is used.
Therefore, the amount of the adsorbent is 33ml.
Water that contained the arsenic of 36µg/l was poured in thecolumnby the flowing water with quantity of 5.6ml/min by using a micro
tube pump.
The time course of the arsenic density was measured at thecolumn exit.
And the arsenic adsorption ability of MP-C was confirmed.

Concentration(Official analysis)
7.1
0.036mg/l
0.03mg/l
0.08mg/l

Table.4 Condition of ExperimentInternal diameter of culum

16mm

Length of filling up

165mm

VolumeAmount of flowing
ＳＶ

ResultTable.5 and Fig.7 show the result of continuous pass water
experiment.
Table.5 Result of Experiment

Total flow
（L）
1
8
10
16
20
24
30
36
40
44

As Concentration (mg/l)

simpleanalysis
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005

Official
analysis
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005
under0.005

pH
5.8
5.8
6.0
6.4
6.5
6.6
6.8
6.9
6.9
6.9

-6-

Fig.6 Setting of Experiment33ml（17.1g）
336ml/h
5.6ml/min
10.1h-

0.012

7

0.01

6.8
6.6

0.008

6.4

0.006

6.2

0.004

pH

As Concentration (mg/l)

Arsenic was treatable below environmental standards
from the outcome of the experiment.
The symptom of the saturation of MP-C was not seen.
Moreover, because the raw water density was 0.036mg/l
and a low concentration, it has been understood that it canalso process the arsenic polluted water of the fairly low
concentration.
＊ The amount of the arsenic wear in this experiment
was 0.093mg/g. Moreover, with a past performance,
2,375L can be processed.

6

0.002

5.8

0

5.6
0

10

20

30

40

Total Flow (L)Fig.7 Result of Experiment

Experiment 2
As for the arsenic contained in the wastewater in tha pit of Torokyu,
the arsenic removal performance of the adsorbent was confirmed with the continuous pass water experimentusing MP-C (our newly developed arsenic adsorbent)
Raw water properties
The raw water properties are shown in Table.6.
Table.6 Characteristic of raw water

Concentration(Official analysis)
7.8
0.11mg/lpH
As

Bench scale column examination
In the column examination, a plastic column filter that is 16mm in the
diameter and 155mm in length was used.
Therefore, the amount of the adsorbent is 31ml.
Water that contained the arsenic of 0.11mg/l was poured in thecolumn by the passing water with the quantity of 5.0ml/min by using a
micro tube pump. The time course of the arsenic density wasmeasured at the column exit. And, we confirmed the arsenic
adsorption ability of MP-C.

Table.7 Condition of ExperimentInternal diameter of culum

Result
The result of the continuous pass water experiment is shown in Table.8.

-7-

Length of filling up
VolumeAmount of flowing
ＳＶ

16mm
155mm
31ml（15.5g）
300ml/h
5.0ml/min
9.7h-AsConsentration
Environmental
Standard
pH

Table.8 Result of ExperimentAs

Total flow
（L）

1
6
10
15
20

Concentration(mg/l)
Official
analysis
under0.005
under0.005
under0.005
under0.005
under0.005

pH

6.8
7.3
7.3
7.3
7.3

Fig.8 Setting of Experiment

Field survey
MyanmarThere was a request through Dr. KUnio Watanabe of The Geosphere
Research Institute of Saitama University（GRIS), who is the director ofJapan Myanmar Interchange Association (AJMMC). The survey of thearsenic pollution underground water in the pollution area was carried out.
We had meetings and workshops with Ministry of Public Health of
Myanmar, the Rangoon Institute of Technology, the Myanmar maritime
affairs universities, the industry associations of Myanmar.
Information including the purification processing experiment was
exchanged.
We visited Myanmar from September, 24th to September, 27th, 2005.
The performance of the field survey and the arsenic adsorbent waschecked.
When we visited the laboratory of Ministry of Public Health in Rangoon,
Fig9 Three Pot Filtration System Setup
we also observed jar type filtration system (3pot filter).
The filter media were natural sand including iron, river sand, gravel, brick rubbishs, minute sand, the activatedcarbons, and the crushing activated carbons.
As a result, both system could treat the one of 100ppb arsenic desity
below the detection limit.
The excellent performance and high technology of MP-C were proven.
Moreover, We demonstrated the arsenic removal by MP-C for the
Ministry of Transport by using the water gathered in the well in the
Irrawaddy river delta region.
We chould show the changes that the water that had browned with theiron content becomes transparent.
Moreover, after brownish water was passed MP-C water, the arsenic
density was removed till about 5ppb (1/100).
Fig.10Three Pot Filtration System
It was a high appraisal.
Future tasks are to grope for better use by using MP-C with the jar filtration system.
Moreover, there are some to action assignment remained such as possibility of manufacturing MP-C in the locale,the investigation of the raw procurement, and more experimental proof test on site.

Bangladesh-8-

We visited Bangladesh from July, 3rd to July, 6th, 2006 with assistant professor Mr. Sezaki, the Department ofCivil and Environmental of at Miyazaki University.
We surveyed the DTW construction site and the purification processing site.
The purification and the measures in Bangladesh were the construction of the deep well, Gravel Sand Filter, Rain
Water, and UNICEF's arsenic removal devices.
Neither purification nor countermeasures were able to obtain a safe drinking water.
Arsenic that exceeded the environmental standards
value was detected even as for the water pumped up
from the deep well.
The filtration method called Gravel Sand Filter
in which water was poured from the gravel to the layerof sand. The treatability was depended upon quality of
raw water.
The Gravel Sand Filter could treat low density arsenic
polluted water, but it could not do high density with low
Fig.10 Gravel Sand Filter
iron concentration
The arsenic removal device of UNICEF is anabsorptive treatment with sand filtration and active
alumina.
This device is very expensive, the manufacturer checkis every two years and safety is low.
We felt that recovering the administration, before thearsenic processing took place, was necessary, and theFig.11 Gravel Sand Filter (L: Raw Water R: Treated Water)
system making by the resident was also necessary.
When such a system is established, the managementof the arsenic removal device by the resident becomes possible.

-9-Summary
The adsorbent that is able to purify the arsenic polluted water 0.001(detection limit)or less was developed. To
confirm the adaptability for the filtration processing method, the laboratory experiment was held.
As a result, regarding the coagulation treatment and processing with active alumina, adding oxidant is necessary
to make three values arsenic to five values and pH adjustment is also necessary to set pH to the appropriate
range for processing. However, these processing was not necessary in the arsenic adsorbent that our company
had developed. It has been understood that the influence of the coexistence material is hardly received andselectivity to arsenic is very high. As for the use propriety pH is about neutral, and the amount of this arsenic
adsorbent for each unit adsorption is about 5mg/g. Moreover, the adsorption ability similar to five values wasshown in three values arsenic. he manufacturing method that can develop a more efficient adsorbent andmass-produce it at a low price is examined as future tasks.
The address of thanks:
We sincerely would like to express our gratitude for undertaking this research, and cooperating people concerned
and related to assistant professor Mr. Sezaki, the Miyazaki University, Dr. Watanabe of Saitama University.

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