adsorption of cadmium and chromium using activated carbon derived from carica papaya seed

7/29/2019 ADSORPTION OF CADMIUM AND CHROMIUM USING ACTIVATED CARBON DERIVED FROM CARICA PAPAYA SEED.

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Continental J. Water, Air and Soil Pollution 3 (1): 12 16, 2012 ISSN: 2251 - 0508

Wilolud Journals, 2012 http://www.wiloludjournal.comPrinted in Nigeria doi:10.5707/cjwasp.2012.3.1.12.16

DETERMINATION OF CALCIUM, MAGNESIUM AND TOTAL HARDNESS CONCENTRATIONS

IN DRINKING WATER SUPPLY IN EBONYI STATE, NIGERIA

1Joseph N. Afiukwa,

2Celestine A. Afiukwa and

3Wilberforce Oti

1,3Department of Industrial Chemistry, Ebonyi State University, Private Mail Bag 053 Abakaliki, Nigeria.

2Department of Biochemistry/Biotechnology, Ebonyi State University, Private, Mail Bag 053, Abakaliki,

Nigeria.

ABSTRACT

The status of public water supplies from different water sources in Ebonyi State comprising 23underground, 7 spring and 22 surface water samples were studied. Fifty two samples were

analyzed for calcium, magnesium and total hardness concentrations using EDTA titration Method.

The results of three replicate determinations across nine Local Government Areas studied

indicated an average total hardness of 134.13 + 15.60 mg/L CaCO 3 during the rainy season (RS)

and 128.8 + 16.1 mg/L CaCO3 at the dry season (DS) for groundwater, 65.55 + 2.20 mg/L CaCO3

(RS) and 65.07 + 2.21 mg/L CaCO3 (DS) for surface water and 17.2 + 2.1 mg/L CaCO3 (RS) and

17.8 + 2.0 mg/L CaCO3 (DS) for the spring water samples. The results of the analysis showed that

groundwater in most parts of the State are hard compared with the WHO guideline limits, while the

spring and surface waters are soft based on the WHO and U.S.-EPA guideline classifications. The

results also indicated high level of calcium hardness in comparison with the magnesium hardness

for both the ground and surface waters. The health and economic impacts of both hard and soft

water types are discussed.

KEYWORDS: Water Hardness, Health Effects, Ebonyi State, groundwater and Surface water

INTRODUCTION

Water is said to be hard when it does not lather readily with soap. A considerable amount of soap is

required for such water to produce lather. Groundwater is generally hard compared with surface water. This

however depends on the local geology and the nature of soils over which the water traverses. Therefore

hardness of water may vary considerably between locations. Dissolved calcium and magnesium ions have

been identified as the major contributors to hardness in natural waters (Ademoroti, 1996 and Miroslav and

Vladimir, 1999). Some other polyvalent cations such as aluminium, iron, magnesium, strontium and zinc

may also contribute to hardness, but their effects is very insignificant due to their low concentrations in

natural waters (Ademoroti, 1996 and Miroslav and Vladimir, 1999). These ions may be present in

significant concentrations especially in industrial wastewater (Ademoroti, 1996). In an environment, such

as Ebonyi State, dominated by limestone (CaCO3), gypsum (CaSO

4.2H

2O) and dolomite (CaCO

3.MgCO

3),

enough of these minerals ordinarily dissolve particularly in a low pH soil, to furnish Ca2+ and Mg2+ ions in

water. The dissolution process is usually enhanced in aquifers with a relatively high microbial activity,

which produces carbon(iv)oxide in water. The CO2 gas lowers the water pH thereby shifting the carbonate

balance towards the hydrogen carbonate (Smith in Lettterman, 1999),

i.e CaCO3 + H2O + CO2 Ca(HCO3)2.

This acidic condition causes a greater dissolution of calcium and magnesium salts in the aquifer rocks.

Water hardness is classified into carbonate (temporary) and non-carbonate (permanent) hardness. The

temporary hard water is due to the presence of hydrogen carbonate of Ca2+

or Mg2+

ions, while permanent

hard water is caused mainly by the presence of chlorides and sulphates of calcium or magnesium. The total

hardness of water is the sum of calcium and magnesium hardness expressed as mg/LCaCO3. Hardness in


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Joseph N. Afiukwa et al.,: Continental J. Water, Air and Soil Pollution 3 (1): 12 16, 2012

excess of the WHO permissible limits renders the water unpalatable for drinking, hinders cooking orbaking and impedes laundry works as well as increases the chances of corrosion and encrustation in heated

metallic pipelines or industrial boilers (Stocchi, 1990).In addition to the cost implications in laundries, very

hard water is also undesirable for use in the beverage, food, batteries, paper mills, tanneries and textile

industries (Gerard, 1998). Beside the beneficial effects of hard water such as the development of a healthy

teeth and bones, neutralization of acid deposition and reduction in the solubility of toxic metals, the status

of water whether hard or soft has also been associated with some health-related problems. The purpose of

this study therefore, is to evaluate the levels of hardness in public water supplies in Ebonyi State. The

results would serve as a baseline data for water quality, which may be required for domestic, agricultural,

recreational and industrial uses.

MATERIALS AND METHODS

Fifty-two (52) water samples were randomly collected from nine, out of the thirteen Local Government

Areas of Ebonyi State in February through December, 2007 and assessed for calcium, magnesium and total

hardness concentrations. The samples were collected in two seasons, dry season (February, October and

December, 2007) and rainy season (June, July and September) of the same year. The samples were stored

separately in plastic bottles previously washed with conc.HNO3 and later rinsed with the sampled water

during sampling. The calcium and total hardness were determined by standard methods using ethylene

diaminetetraacetic acid (EDTA) complexometric titration (Ademoroti, 1996; Mendham et-al, 2000 and

Ming, 2001), while the magnesium hardness was calculated by the difference between the total and calcium

hardness.

Descriptive statistics was used to analyse the data

RESULTS AND DISCUSSION

The concentrations of calcium, magnesium and total hardness in different water supply sources across the

State were studied at two seasons and the results are presented in Table 1. The results were compared with

the WHO and U.S-EPA guideline limits. The WHO classified water that contains < 50 100 mg/LCaCO3as soft and > 100 mg/LCaCO3 as hard, while US-EPA classified water with 0 60 mg/L CaCO3 as soft and

> 60 mg/LCaCO3 as hard. The results of this study indicated an average total hardness of borehole (B/h)

and well waters as 134.13 + 15.64 mg/LCaCO3 at the rainy season and 128.78 + 16.10 mg/LCaCO3 during

the dry season. This represents an excess of 25.4 % and 22.3 % at both seasons respectively when

compared with the WHO minimum reference values for total hardness. The surface water samples showed

a mean total hardness of 68.5 + 7.7 mg/LCaCO3 at the rainy season and 67.95 + 7.8 mg/LCaCO3 during the

dry season indicating that the water is moderately soft by the same standards.

Table 1: Mean Seasonal Variations of the Levels of Hardness (mg/LCaCO3) in water supplies in Ebonyi StateParameters Ca-hardness Mg-hardness Total hardness

Mean + SE r90.30 + 11.59 36.4 + 5.07 134.13 + 15.64GW d91.80 + 12.64 35.9 + 7.50 128.78 + 16.10Range r8.0 200.00 0.0 80.0 10.0 312.00

d10.0 210.00 0.0 80.0 11.0 290.00

Mean + SE r45.75 + 5.49 22.72+ 2.71 68.50 + 7.70

SW d41.41 + 5.59 22.52 + 2.72 67.95 + 7.80

Range r8.0 102.00 4.00 64.0 12.0 166.0d8.0 102.00 4.00 64.0 13.0 166.0

Mean + SE r11.71 + 1.0 5.84 + 0.7 17.16 + 2.11SPW d11.96 + 1.8 5.21 + 0.6 17.80 + 1.96Range r9.0 18.0 3.00 8.4 8.0 26.00

d5.0 19.0 3.00 7.0 8.0 23.00

GW= groundwater, SW= surface water, SPW= spring water, SE= standard error, r = rainy season

d = dry season.


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The spring water samples on the other hand are relatively very soft as the results showed an average totalhardness of 17.16 + 2.11mg/LCaCO3 at the rainy season and 17.8 + 1.96 mg/LCaCO3 during the dry

seasons. In all the samples, calcium ions contributed a higher percentage of the total hardness than

magnesium ions as the results indicated. The concentration of calcium hardness more than doubled the

values obtained for the magnesium hardness. This is in line with similar studies conducted in the area

(Afiukwa, 2010). A post-hoc comparison of the results between the seasons reveals that there were no

significant seasonal variations in hardness concentrations for both classes of water.

However, significant variations existed between the levels of hardness in groundwater compared with the

surface water samples. It is observed from Fig.1, that except the spring water samples, which of course are

not widely distributed across the State, the groundwater samples obtained from boreholes and public wells

indicated a higher degree of hardness than surface water samples.

The observed dip in Fig.1 indicates hardness levels of spring and rain waters. Although spring water is an

aspect of underground water, those assessed within the study areas (Afikpo North and South) were found to

be very soft contrary to expectations. This is attested to by the low pH range observed for the spring water

samples (4.2 5.6). It may also mean that the concentrations of limestone, dolomite and other hardness

causing mineral salts in the type of rock that dominated the area are very low. The observed results are

perhaps indicative of the local geology of the study areas. The grade of limestone deposit in the area is

high. This among other factors such as the topography of the land forms and nearness to railway line may

have influenced the citing of the defunct Eastern Nigercem in the 1960s, a cement producing factory at

Nkalagu near Abakaliki Metropolis. More of such deposits of limestone have been identified in several

locations within Ebonyi State (Oyibe, 2000). Current research efforts have determined the quality and

quantity to be high enough to commence the State owned cement factories at the three senatorial zones of

the State. In addition to this wide spread of limestone deposits, the high solvent power of water, its slow

flow-rate and the longer residence time within the aquifers, contamination of groundwater by calcium ions

are expected compared with the effects of human activities such as quarries on surface waters.

Fig. 2 shows the mean distributions of calcium, magnesium and total hardness concentrations in

groundwater across the Local Government Areas studied at the two seasons. There were significant

variations of this parameter in groundwater within the study areas. The total hardness across the L.G.As

decreased in the order: Izzi (Iz) > Ezza North (Ez) > Ebonyi (Eb) > Abakaliki (Ai) > Ikwo (Ik) among the

areas with high hard water in excess of the guideline limits.

Fig.1: Mean concentrations of total, calcium and magnesium hardness in ground andsurface water supply sources in Ebonyi State during the rainy and dry seasons

Water sources

020

40

60

80

100

120

140

160

RS DS RS DS RS DS RS DS RS DS RS DS RS DS RS DS RS DS RS DS

WHO B/h Well Spring Mean River Stream Dam Pond Tap Rain

Waterhardness(mg/L) Ca Hardness

Mg Hardness

Total hardness


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Fig.2: Concentrations of total, calcium and magnesium hardness in groundwatersupply in different L.G.As of Ebonyi State during the rainy and dryseasons.

2040

6

8

10

12

14

16

18

20

WH A

E

E

I

Ik Afs AfnSample Areas

Mg Hardness DSTotal hardness RSTotal hardness DS

Ca Hardness RSCa Hardness DSMg Hardness RS

Waterhardness(mg/L)


The WHO recommended 100 mg/LCaCO3 as the minimum guideline limit for total hardness in drinking water.

Water supply meant for public consumption which hardness is in excess of this value is undesirable (Stocchi,

1990) and may constitute a health risk especially for the teaming population within the study areas who may

depend on such water for their regular needs. Health Experts have shown that hard water taken for a long period

especially that containing magnesium sulphate prolongs the duration of thrombin induced shape changes inbovine platelets and can also weaken the stomach permanently (Austin, 1984). On the other hand, soft water is

usually acidic and has been linked with incidences of cardiovascular diseases as well as acidosis (Miroslav and

Vladimir, 1999, Ming, 2001). Consumers of such water may be predisposed to high dosage of chemical toxins

because of acid enhanced metal dissolution. According to Medical Experts, even mild acidosis may lead to

cardiovascular damage, constriction of the blood vessels and reduction in oxygen level (Ogundipe and Obinna,

2008). Other side effects in agricultural, industrial and other civil uses have been reviewed (Stocchi, 1990 and

Gerard, 1998). On civil uses, it hinders cooking, baking and impedes washing with soap due to the precipitationof soap as scum. On industrial level, the furring of kettles and clogging on electrical appliances or pipelines

causes encrustation, lowers the efficiency of heat exchange and causes local supper-heating and explosion

(Austin, 1984). In food processing and beverage industries, paper mills, tanneries, dyestuff and electrical units

such as batteries cannot be fed with very hard water (Gerard, 1998). In textiles and laundries, hard water wastes

soap and detergents. Hard water however is important in the development of a healthy teeth and strong bones.Its scale formation on pipelines prevents possible dissolution of toxic metals such as lead and arsenic and

reduces the solubility of these metals.

CONCLUSION

The study has shown that virtually all groundwater supplies in Ebonyi State are moderately hard. The high levelof calcium mineral salts in the State indicated in this study is yet to be fully exploited. Finally, the study

provides a baseline data on water hardness in the State.

ACKNOWLEDGEMENT

The authors acknowledge with thanks the Department of Industrial Chemistry Laboratory, Ebonyi State

University for the provision of reagents and materials used in the analysis.

REFERENCES

Ademoroti, C.M.A (1996). Standard Methods for Water and Effluent Analysis, Foludex Press Ltd; Ibadan

pp.40 43

Afiukwa, J. N. (2010). Comparative Studies on Hardness Concentrations in groundwater supply fromAbakaliki, Ikwo and Ishielu L.G.As in Ebonyi State, Nigeria.J. Poll. Res. 29(4): 727-731.


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Austin, G. T (1984). Shreves Chemical Process Industries. McGraw-Hill Book Company, New York p. 19

Encyclopedia of Chemical Technology 2nd Ed. Vol.21 p.693

Gerard, K. (1998). Environmental Engineering; Irwin / McGraw- Hill Book Company, Singapore pp.1, 456

Mendham, J; Denney, R.C; Barnes, J.D and Thomas, M.J.K (2000). Vogels Quantitative Chemical analysis 6th

ed; Pearson Educational Ltd. Singapore pp. 385 -386

Ming HO.YU (2001). Environmental Toxicology: Impacts of Environmental Toxicants on Living Systems.

Lewis Publishers, London pp.151 179

Miroslav, R and Vladimir, N. B (1999). Practical Environmental Analysis, Royal Society of Chemistry, U.K

p.178

Ogundipe, S and Obinna, C. (2008). Safety of Table Water goes beyond the Bottle In: Good Health

Weekly, Vanguard Newspapers, Tuesday, May 20, 2008 p.42

Oyibe, S. (2000). Investment Potentials, Tourism and Natural Resources Base for Raw Materials in Ebonyi

State. Ministry of Commerce, Industry and Technology Publications, Abakaliki pp. 21-23.

Smith, S.A In: Letterman, D.R (1999). Water Quality and Treatment: A Handbook of Community Water

Supplies 5th

ed. American Water Works Association. McGraw-Hill Inc. New York p.21

Stocchi, E. (1990). Industrial Chemistry Vol.1 Ellis Horwood, New York pp.131-132

Received for Publication: 04/02/2012

Accepted for Publication: 21/03/2012

Corresponding Author

Joseph N. Afiukwa,Department of Industrial Chemistry, Ebonyi State University, Private Mail Bag 053 Abakaliki, Nigeria.

Email:[email protected]

adsorption of cadmium and chromium using activated carbon derived from carica papaya seed

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