LOW COST BIO-ADSORBENT

The by-products of man’s actions have resulted in severe waste burden on Earth. Rapid developments in technology and lifestyle have accelerated the addition of contaminants into air, water and land rendering it unsafe for organisms. Release of pollutants from various sources like domestic, agricultural and industrial sectors has dramatically modified the quality of water thereby causing harm to aquatic organisms. In extreme cases, it can even kill aquatic organisms. Waste water released from domestic households contains several harmful residual substances like detergents, oils, colours, dyes and various salts. Agricultural activities add excessive fertilizers, pesticides and herbicides into the nearby water bodies. Effluents released from industries release toxic chemicals like heavy metals, chemicals(organic or synthetic) to the aquatic ecosystems. The best solution to water pollution is to prevent it from happening. Separation of pollutants at source is the best method to control water pollution. This includes physical, biological and chemical separation to convert the dirty water to clean and usable forms before release.

This study reveals a novel and cheap method of cleaning waste water from domestic and industrial sources by utilizing one of the most under-utilized agricultural wastes. The present study is based on the scientific principles of Adsorption by immobilizing the contaminants with the help of corn cobs. Corn is a major crop plant, every part of which is utilized except the cob. In this project an attempt was made to utilize this less-utilized plant part to clean one of the most precious natural resources, water.

 

 

 

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 I, Sripada Srisai Lalita Prasida, visited many places during my school days before settling down in the pristine hinterlands of South Odisha. I began   my studies in the hilly meadows of Nagaland, then in the Gangetic plains of West Bengal and finally in parts of the Western Ghats that have the distinction of being the secondary centre of origin of rice and the Natural home to more than 50 different aboriginals. Currently, I am living in Damanjodi, famous for the presence of Asia’s largest Bauxite Refinery located in the district of Koraput, Odisha. I am a student of class IX reading in Delhi Public School, Damanjodi. I like to visit nearby villages to observe their lifestyle. They live in harmony with their surroundings by utilizing natural resources, without affecting the ecological web. Their lifestyle revolves around agriculture- in cultivating many varieties of crops. This developed an interest in me to focus on Science to develop something new, related to agriculture. In one of my encounters with a tribal farmer, I came to know about the low utilization of corn cobs, which ignited me to find out some ways to use this agricultural waste. Thus I will pursue a career in Agricultural studies and serve for local people.

Winning the Google Science Fair will boost my insight and help me to work further for solving local problems. The Scientist who created interest in me is Dr. M. S. Swaminathan, the Father of the Green Revolution in India.

 

 

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Maize is the common name for the cereal grass that is widely grown for its use as a staple food and livestock fodder. Corn is India’s third most important cereal crop after wheat and rice.  All the parts of the maize plant are used for various purposes. However, corn cobs are one of the most plentiful and important agricultural wastes in maize cultivation. Immature corn cobs are boiled and eaten by the local farmers. But mature cobs are either used as fuel, resulting in air pollution and global warming. Interestingly, corn cobs are not even eaten by animals as they choke their digestive tract, and may lead to death. Thereby, heaps of corncobs are found dumped in areas where they are cultivated.

    After maturation, the ears of corn are hand-picked and sun dried to remove the kernels by machine. The kernels are sold to industries and the left-out cobs are either thrown away in isolated places or buried under the soil to restrain the animals to feed them. Thus, a matter of primary concern is the economical and efficient utilization of these corn cobs for a purpose. As they are porous, they can be used as water filtrates.

     There are many advantages of using corn cobs; they are eco-friendly, cheap, easily available, easy to handle and thus can be used by all. This will definitely help people to clean water, the very worth of survival and the cobs can be marketed, like kernels.

 

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The study reports adsorption of contaminants, colour dyes and suspended particles from domestic waste water and industrial effluents by corn cobs. The corn cobs were collected from local farmers, washed thoroughly with water, sun dried, cut into long and small pieces, ground to powder and burnt in suitable conditions to form activated charcoal. These processes were done to effectively study the phenomenon of adsorption of contaminants in waste water by allowing contaminated water to  pass through different layers of corn cobs. Visual observation and simple  physico-chemical tests were conducted to study the presence or absence of colour dyes, suspended particles, oxides of salts, detergents, oils and heavy metals in waste water released from domestic households and industries. The study revealed that agricultural bio-wastes like corn cobs are cheap and best adsorbents to clean domestic and industrial waste water. It is a cost-effective and simple to follow technique.

Adsorption is regarded to be easy and effective process for the cleaning of waste water (3&5). Bio- adsorbents are commonly used to clean water. Fehintola et al.(2015) reported the adsorption of Lead, Nickel and Cadmium by powdered egg shells. Adsorption of Lead by powdered corn cobs was also reported by Fehintola et al.(2015 a). Ismail et al.(2009) reported the adsorption of Cadmium by the powdered corn cobs. Nada et al.(2009) reported the increased efficiency of corn cobs towards metal ions sorption by incorporating certain functional groups, e.g. phosphate, sulfate and carboxylic groups. The adsorption of Fluoride from water using powdered corn cobs was investigated by Parker et al. (2006). They identified that 90 to 120 minutes was the best contact time for maximum fluoride adsorption. Binding of Cadmium by hemi-cellulose of corn cobs was also reported by Muchlisyam et al.(2013).  So, the study was designed to control and check water pollution from domestic and industrial sources by using an agricultural waste.

 

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The corncobs were collected from local farmers and sun dried for one month. A cob was taken whose pith was removed carefully from the top to make a hole at the centre of the cob without piercing the other end for the pilot experiment. Then, 50 ml of domestic effluent collected from kitchen drain pipe was allowed to pass slowly through the central hole of the cob and the filtrate was ccollected. The filtrate was subjected to several qualitative tests like the presence and absence of oxides of salts, detergents, oils, coloured dyes, suspended particles etc . Test for detergent was done by hand shaking the filtrate to mark foam. Visual observation was made to find out the presence   of coloured dyes. Chemical tests were conducted in school chemistry laboratory to find out their presence or absence in the test material.

After this known quantities of chemicals like Ca, Cu, Mg, Pb, Sr, Cr, robin blue, lac dye, shampoo, oils were added to the pre-treatment water and allowed to pass through different layers. Corn cobs are taken in five separate used bottles of 2 lt capacity each containing 400 g of dried longitudinal sections, 400 g of dried small pieces, 400 g of powdered corn cobs, 400 g of activated charcoal of corncobs and 500 g fine sand(Last layer) each. The filtrate was collected and tested for the presence or absence of the chemicals as mentioned below.

The following parameters like Total Suspended Solids, BOD, COD, Oil, Grease,   dyes, Cu, Mg, Pb, Sr, Ca, and Cr were studied for the pre and post treatment water to find out the rate of absorption by corn cob. Chemical tests are conducted in the school laboratory and test for BOD, COD, TSS, Dye were done in NALCO chemistry lab by spectrophotometer.

An artificial tank was designed in a plastic tub with the capacity of 20 l having pond water and soil as bottom floor. Corn cobs were tied on bamboo sticks which in turn were buried in the floor of the pond, so that the cobs were immersed. The ser up was allowed to stand for two weeks to study the rate of adsorption by corncobs.

Laboratory staff members of school and NALCO Chemistry Lab helped me during the laboratory work.

Qualitative Tests for :-

Cu -

2CuCl2 + K4[Fe(CN)6] -------------> Cu2[Fe(CN)6]+4KCl.

 ~ {Cu2[Fe(CN)6] is chocolate brown color}

 

Pb -

Pb(NO3)2 + 2KI -----------> PbI2 + 2KNO3

~{PbI2 forms yellow precipitate}

 

Mg salts -

MgCl2 + NH4OH + (NH4)2HPO4 ----------->

  Mg(NH4)PO4 + 2NH4Cl + H2O

~{Mg(NH4)PO4 forms white precipitate}

 

Sr -

SrCl2 + (NH4)2SO4 --------------->

 SrSO4 +  2NH4Cl

~ { SrSO4 forms white precipitate}

 

Ca salts -

1) CaCl2 + 2CH3COOH --------------->

 ( CH3COO)2 Ca + 2HCl

2) (CH3COO)2 Ca + (NH4)2C2O4 ---------->

  2CH3COONH4 + CaC2O4

~{ CaC2O4 forms white precipitate}

 

Cr -

Cr(vi) in acidic medium gives magenta colour.

 

 

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It was observed that most of the coloured substances present in the effluents are adsorbed in the charcoal layers. The suspended particles are adsorbed in the chaff layers of both long sections and pieces of corn cobs. Maximum adsorption of gasoline waste was found in the powdered corn cob layers. The rate of adsorption was directly proportional to the surface area of the adsorbents. Finally, the results of the chemical analysis were presented in a Table-01 and Table-02 showing the presence and absence of contaminants in the domestic and industrial effluents before and after the treatment.

 

Table-01: Showing the results of Presence/Absence of contaminants in Domestic waste water before and after the treatment:

Name of the waste

Present/Absent before the treatment

Present/Absent after the treatment

 Ca salts 

Mg salts

PRESENT

PRESENT

ABSENT

ABSENT

Detergents

PRESENT

ABSENT

Gasoline waste(Oils & Grease)

PRESENT

ABSENT

Colored Dyes

PRESENT

ABSENT

Suspended Solid Particles

PRESENT

ABSENT


 

Table-02: Showing the results of Presence/Absence of contaminants in Industrial waste water before and after the treatment:

Parameters

Present/Absent before the treatment

Present/Absent after the treatment

Cu 

Pb

Sr

Cr

PRESENT

PRESENT

PRESENT

PRESENT

ABSENT

ABSENT

ABSENT

ABSENT

BOD

HIGH

LOW

COD

HIGH

LOW

Colored Dyes

PRESENT

ABSENT

Gasoline wastes

PRESENT

ABSENT

Total Suspended Solids (TSS)

PRESENT

ABSENT

 

Similar results were also observed in the water quality of the artificial tanks before and after the treatment with corn cobs showing the adsorption of contaminants and suspended particles. The rate of adsorption was also related to the surface

Table-03: Showing the results of Presence/Absence of contaminants in artificial tank water before and after the treatment:

Name of the waste

Present/Absent before the treatment

Present/Absent after the treatment

Ca  salts

Mg Salts

PRESENT

PRESENT

ABSENT

ABSENT

Suspended Solid

Particles

PRESENT

ABSENT

 

     
     
     

 

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From the above observation it was concluded that Corn cobs were found suitable adsorbents because of their high mechanical strength, rigidity and porosity. Hence, contaminants like oxides of salts, detergents, suspended particles, coloured dyes, oil and grease get adsorbed in the surface of the corn cobs. Some of the heavy metals are also adsorbed by corn cobs. If the drain pipe of the household is connected to a chamber having different layers of corn cobs in partition layers or to an S-trap pipe having corn cobs, it will separate about more than 70-80 % of contaminants including suspended particles from the waste water. Similarly the factory out let pipes carrying effluents must be opened to five inter-connected chambers having long slices of corn cobs, pieces of corn cobs, powder of corn cobs, activated charcoal of corn cobs and fine sand for the easy adsorption of TSS and chemical toxicants both organic and inorganic. Corn cobs fitted to bamboos buried on the ground floor of the ponds and allowed two to three weeks to stand can be useful for cleaning of water in ponds, tanks and rivers. This is also useful to clean overhead water tanks of individual households and community tanks.  

Thus, Corn cobs adsorb contaminants from surface water and prevent their entry into groundwater. Indirectly corncobs help to decrease the temperature of water by adsorbing the suspended particles which store heat and raise water temperature. These also help in preventing shock loading from hard surfaced parking lots. It is a cheap and low cost method using one the less utilized agricultural bio-wastes of the globe. This will open a new market value of the corn cobs which are considered as bio-waste till date. However, further chemical and physical examinations are necessary to make a marketable product out of corn cobs to adsorb contaminants from the domestic  and industrial effluents.

Advantages of Corncobs:-

01) Simple

02) Efficient

03) Cost effective

04) Eco-friendly

05) Feasible

06) High mechanical strength

07) Locally Available

08) Reusable

09) Cheap Technology

10) Porous

11) Easy to Use

12) No Maintenance

13) No Operational Skill

14) Not edible 

15) AN AGRICULTURAL WASTE.

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1) Fehintola EO, Obijole OA, Amoko JS, Joke IA (2015). Adsorption Equilibrium Isotherms of Pb, Ni and Cd onto powdered Egg Shells. lfe  Journal of Science, volume. 17(1):141-162.

2) Fehintola EO, Amono JS, Obijole OA, Oke IA (2015 a). Pseudo second order kinetics model of adsorption of Pb onto powdered corn cobs: comparison of linear regression methods, Direct Res. J. Chem. Mater. Sci., vol. 3(1):1-10.

3) Huang C, Cheng WP. (1997). J. Copied Interface Sci. 188: 270-274.

4) Ismail A, Side DB, Joke IA, Otun JA, Olarinoye NO, Luk man S, Okuofu CA (2009). Adsorption kinetics of Cadmium ions onto powdered corn cobs. Canadian Journal of Chemical Engineering, 87:896-909.

5) Kato M, Kudo S, Hattori T. (1998), Bull. Chem. Soc. Japan, 49:267.

6) Muchlisyam, Harahap U, Silalahi J, Alfian Z (2013), Binding ability of corn cobs hemicellulose toward Cadmium. AJAC,4: 86-93.

7) Nada AMA, Mahdy AA, El-Gendy AA(2009). Cationic exchangers from corn cobs. Bio- Resources , 4(3): 1017-1031.

8) Parmar HS, Patel JB, Sudhakar P, Koshy VJ (2006). Removal of Flu from from water with powdered Corn Cobs. Journal of Environment. Science & Envy. Vol. 48(2): 135-138.

    I am deeply indebted to my parents   Mrs S.  Kalyani and  Sri Subrahmanya K. S.  for their sincere inspiration and appropriate comments during the project. I wish to acknowledge Smt. Pallabi Mohapatra, my guide teacher for her constant support and valuable guidance. I also wish to acknowledge Master Prateek  Pattanaik student of class 11th for his sincere assistance during the design of the project. I thank my younger sister Pranitha of class 4th for her helping hand during the experimental work. I extend my gratitude to farmers who actually helped me to find the problem and extended their full cooperation during the search. I am equally indebted to all the laboratory staff of Delhi Public School, Damanjodi and NALCO Chemistry laboratory, NALCO, Damanjodi for their co-operation .

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