Environmentally Friendly Way of Cleaning Heavy Metal Containing Sulfric Acid Waste

Ayaka Abe, Sayaka Nomichi, Takuro Tsutsumi, Yongtae Hwang, Kazuya Akiyama, Hitoshi Abe, Yasuhiro Niwa, Yoshito Mayumi, Kazuhisa Matsumoto, Chiya Numako*

High Energy Accelerator Research Organization, Tsukuba, Ibaraki Prefecture, Japan

We would like to thank High Energy Accelerator Research Organization for generously funding our experiment. I would also like to extend our appreciation to the Kalamazoo College Provosts for funding my trip and staff of KEK Summer Challenge for giving us an opportunity to participate in this study.

• Hydroxide method was the most efficient. - Hydroxide and ferrite methods had similar heavy metal removal efficiencies. - Ferrite method requires extra steps for making ferrite. - Ferrite did not form successfully in our experiment.

• The explanations for failures of ion exchange method and ferrite formation will be further investigated by using XAFS.

Waste liquids are produced in places such as industries and school science labs everyday. Converting these waste liquids into harmless states prior to disposition is a crucial process for protecting the environment. However, most of the time, large amounts of artificial chemical reagents are used in this process. In Dr. Chiya Numako’s lab at Chiba University, a student accidentally dropped large metal spoons in a sulfuric acid bath that was intended for cleaning experimental instruments. The student came up with a several methods to clean the waste liquid using environmentally friendly materials, such as seashells and calcined fish bones.

INTRODUCTION

MATERIALS AND METHODSCONCLUSIONS

ACKNOWLEDGEMENTS

RESULTS

-- Leave a minimum of 1/2” margin for all poster sides

B. Hydroxide method C. Ferrite methodA. Ion exchange method

Sample Preparation Methods Sample Analyses←XRF was used for determining the types of heavy metals in the waste liquid sample.

→The concentrations of Fe, Cr, and Pb were measured using ICP-AES.

←UV/Vis Absorption was used for producing a calibration curve for Fe for further verification.

Figure 1. Result of XRF showing the elements that were contained in the waste liquid sample.

Figure 2. A calibration curve made with diluted tris (1, 10-phenanthroline) iron (II) complex. The concentration of the iron contained in the waste liquid sample was determined and indicated on the calibration curve.

Table I. Concentrations of heavy metals in the waste liquid before and after the trials A, B and C. Heavy metal efficiencies in % are also shown.

Table II. Summary of the heavy metal removal efficiencies for trials A, B and C.

Inte

nsity

Energy (keV)

0 5 10 15 20 25 300

5

10

15

20

25

30

Se-ries1;

Trial CTrial B ; 0.00943

f(x) = 0.977554751678 x + 0.034987651007R² = 0.999982264018379

強度/１０５

Concentration (ppm)

Figure 3. A calibration curve of iron made with ICP-AES. Concentrations of waste liquid after Trials B and C are shown. Trial A’s result was outside of the range.

Fe

0 0.02 0.04 0.06 0.08 0.1 0.120

0.51

1.52

2.53

3.54

4.55

Se-ries1; Trial

BSe-

ries1; Trial A

f(x) = 41.7776428571429 x − 0.223928571428569R² = 0.999393756141224

強度/103

Figure 5. A calibration curve of lead made with ICP-AES. Concentrations of waste liquids after trials A and B are shown. The result of trial C was undetermined.

Pb

0 5 10 15 20 25 30 35 40 45 5005

10152025303540

Trial C; 0.912

Trial B; 0.187

Trial A; 36.1

f(x) = 0.8621532 x − 0.0323031000000005R² = 0.99736719231507

強度/105

Cr

Concentration (ppm)

Concentration (ppm)

Figure 4. A calibration curve of chrome made with ICP-AES. Concentrations of waste liquids after trials A, B and C are shown.

Inte

nsity

/105

Inte

nsity

/105

Inte

nsity

/103