CaRBoKem: A Biolter to Treat Heavy Metals by using the Household Waste Products

Environmental toxic waste from heavy metals along with minerals within the waste matter is one of the most signicant issue in an Asian country. The activities like industrial operations particularly mining, agricultural processes and disposal of industry waste materials; their concentration has redoubled to hazardous levels. Major metals in industrial sewage represent Cu, Cr 3+ and Pb etc. So far, varieties of inexpensive strategies are reviewed for the removal of these metals. The various processes include chemical precipitation, reverse diffusion, electro qualitative analysis, nanoltration and oatation. But these strategies have many disadvantages like high chemical agent demand, unpredictable metal particle elimination, and production of unhealthful sludge. Surface absorption method being terribly straightforward, economical, effective and versatile has become the most popular strategies for removal of unhealthful contaminants from waste matter. This paper gives a new idea for the utilization of natural materials as adsorbents for signicant metal removal from industrial waste water. The components used are mustard plant roots, human hair and some common house hold waste products such as, egg shell and coconut shell. Utilizing their adsorbent properties in an ecient way, it can be used to lter industrial heavy metals which cause pollution.


I. Introduction
These day's toxins are discharged into water leading to water contamination. Numerous heavy metals from various industries like battery plants, metal processing industries, pharmaceuticals, hospitals, mining elds etc. are being discharged into the water bodies leading to unstable water for everyday use [2].Lead, Chromium, Copper etc are the heavy metals that induces toxicity plus carcinogenetic when present in high concentration [3]. In order to obtain dirt free and safe water, toxic chemicals and metals should be eliminated. The standard of our environment is decreasing day by day, means of giant cities reaching saturation points and un t to cope with the rising pressure on their infrastructure [4].Major pollutants that contaminate the environment are sewage and industrial e uents. Most of the industries discharge wastewater. Environmental pollution especially from heavy metals and minerals in wastewater is the major concern in India [5].
Many methods have been undertaken in the process to remove these unwanted contaminants such as physio-chemical methods, a range of biological methods to a large extend nano based techniques. One of the most important treatment processes used in water and wastewater treatment is ltration. In water management, the aim is to fabricate e uent of good criterion so that it can be reused for various purposes [6]. A bio lter is a lter with linked biomass on the lter-media. Bio lters can be trickling lter, horizontal rock lter or granular activated carbon (GAC) or sand lter in water treatment plant. Bio lter applications are found in air, water, as well as wastewater treatment [7]. Bio ltration reduces odour and hydrogen sulphide (H 2 S) emissions by 95% and ammonia 65% approximately. Bio lters are operated in automatically ventilated buildings or on the pit fans of naturally ventilated buildings [8]. A bio lter is a layer of material that is organic, mixture of compost that supports a population of microbes. Bio lter performance is controlled by amount of time the odorous air spends in the bio lter and also the moisture content of the lter material [9].
The bio lter we have prepared with the sole purpose to attain environmental sustainability by using the household waste such as mustard plant roots, eggshell, human hair and coconut shell. Mustard plant roots have high quality adsorbent properties and may be a thriving technique in puri cation of water due to the compounds in roots that contains the amount of nitrogen, sulfur and organic compounds such as carboxylic acids. These acids are charged such that their negatively charged electron pairs are exposed, meaning they can combine with metals in the water that typically contain a positive charge. Eggshells are a very dependable adsorbent due to its carbonate content. Keratin is the main constituent of wool, hair, feathers, horn, and nail. Keratinous materials, wool, feather and hair have been used to absorb metal ions from solution in their native state and with suitable chemical pre-treatment; the adsorption capacity for these ions can be drastically enchanced. The main idea of our project is to see how e cient mustard plant roots, eggshell, human hair and activated carbon are absorbing heavy metals. We have devised our own protocol and decided various parameters which we thought suited the best.

A. Materials Required
Mustard seeds, Egg shell, Human hair, Coconut shell, Bell Jar, Beaker, Soil, 0.5 M H 2 O 2 , 1.5 M ZnCl 2 , 0.1 M HCl and NaOH solutions were used to alter the pH. All the chemicals were of laboratory grade used in our college. The Industrial Water Sample 1 was collected from a sheet metal industry; Industrial Water Sample 2 was collected from a paint industry. We measured the absorbance of heavy metals by Atomic Absorption Spectrometer (AAS).

B. Preparation of solutions
To prepare 0.5 M H 2 O 2 we added 10 g of H 2 O 2 in to 500 ml of deionized water. Likewise we added 10 g of ZnCl 2 in to 100 ml of deionized water to prepare 1.5 M ZnCl 2 .We labeled the samples with respect to their pH, contact time of 60 min and 90 min at room temperature. Afterwards ltered the solutions and absorbance was taken using ASS.

C. Preparation of Adsorbents
Cultivation of Mustard plant roots Mustard seeds were taken and soaked in water for about 5 hours, later laid them on cotton and allowed them to sprout. After sprouting in a tray they were grown for 3 weeks in the soil.

Preparation of Eggshell
Twenty eggshells were collected from daily kitchen waste and washed by normal tap water followed by distilled water. The eggshells were left to dry on blotting paper to absorb surplus water and then subjected to the hot air oven at 50 °C for 2 days. Once totally dehydrated we pulverized and shred eggshells to ne particles with mortar and pestle followed by a mixer. Later we sieved the crushed adsorbent to obtain a homogenous dimension around 0.05 cm.

Production of Activated Carbon
Some amount of coconut shell was cleaned to remove impurities such as coconut ber and sand. Dried under the sun for 7 hours and followed by 3 hours in an oven to obtain charcoal. The charcoal was crushed to 0.5 mm mesh size. About 200 g of this chrushed charcoal was introduced into 1.5 M ZnCl 2 and stirred to form a paste/slurry. This was heated for about 5-6 hours and allowed to chill at room temperature, thus impregnated with ZnCl 2 . This is called doping. The doped charcoal was heated in an electric furnace to 450 o c for an hour and allowed to cool in air. Then it was carefully washed to eradicate traces of ZnCl 2 .

Preparation of human hair
Hair samples were obtained from local barbershops. Human hair samples were washed with detergent and rinsed several times with deionized water and left to dry at room temperature. The hair was cut to an approximate length of less than 5 mm by using scissors. 20 g of washed dried biomaterial was weighed out and soaked in 0.5 M H 2 O 2 and solution was ltered. Finally, the treated and cleaned biomaterials were dried at room temperature.

I I I. Packging Of A Bio lter
The roots of the mustard plant were grown in the soil was cut and kept as rst layer, followed by egg shell layer. The third layer and fourth layer were constituted by human hair and activated carbon respectively.

I V. Method
The industrial waste water containing heavy metal is passed through each layer. This setup for ltration was arranged as layers in the bell jar and the contact time used was 60 min and 90 min respectively. pH and absorption of the sample was checked by subjecting to the AAS.

Effect of pH on Adsorption
The range of pH used was 4-7.The adjustments were done using 0.1 M solution of HCl and NaOH. Later the asks were subjected to contact time of 60 min and 90 min respectively. Then the ltrate was taken and AAS was used to verify the absorption of the heavy metals.

Effect of Contact time on Absorption
After 60 min and 90 min of contact time ltration occurred and the adsorption was checked by using AAS.

V. Results And Disscusion
Effect on pH of Adsorption At lesser pH values the adsorbance was a found to be smaller compared to higher pH values. It could be because at lesser values the adsorption could have been contrast due to the competitive interactions between the heavy metal ions and the hydrogen ions which restrict the adsorption. The presence of carbonate groups in the adsorbents was identi ed at higher pH values. In general best results were obtained at pH 7.

Effect of Contact time on Adsorption
The adsorbance will be higher at larger surface area and contact time. Better results were obtained when exposed for a contact time of 90 min.The results of both ltered and un ltered sample testing were done in the College of Veterinary and Animal Sciences, Mannuthy. The elimination of heavy metals Cu, Pb and Cr 3+ using mustard plant roots, eggshell, human hair and activated carbon as adsorbents was carried out by various parameters such as contact time and pH values. The best results were observed at the conditions, having pH value 7 and contact time of 90 min. As the size of adsorbent was small the competence of adsorption was increased; also these household wastes are economical and the manufacture process is very sustainable. Moreover this will not cause any damage to the future of environment and it is very safe to use. At the primary stage itself the ltration was achieved and it was found that all these adsorbents were nest for adsorption of heavy metals from waste water. Upgrading the size of particles to nanoscale was found to be futuristic. Also element modi cations may be done on the household waste to amplify the absorbance capability.    CarbokemGraphicalAbstract.docx