Tools for Assessment of Student Learning Outcomes written for faculty Introduction Every good gardener knows that the key to healthy plants is a fertile soil. Plants get water and nutrients from soil and it is the inherent characteristics of the soil in combination with environmental factors that determine soil fertility. Soils are complex and dynamic ecosystems with communities of organisms. Like all ecosystems they have a food web that may include bacteria, fungi, algae, protists, insects, worms, plant roots and burrowing animals.
This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This study was carried out to examine the adsorption capacity of the low-cost Adsorption experiment ATS for the removal of heavy metals from textile effluents.
The influence of contact time, pH, Temperature, and adsorbent dose on the adsorption process was also studied. Results revealed that adsorption rate initially increased rapidly, and the optimal removal efficiency was reached within about 1 hour.
Further increase in contact time did not show significant change in equilibrium concentration; that is, the adsorption phase reached equilibrium. The adsorption isotherms could be fitted well by the Langmuir model. The value in the present investigation was less than one, indicating that the adsorption of the metal ion onto ATS is favorable.
Results indicate that the freely abundant, locally available, low-cost adsorbent, Teff straw can be treated as economically viable for the removal of metal ions from textile effluents.
Introduction Demands of clothing and apparel increase with the improving sense of fashion and lifestyle; thus textiles are manufactured to meet the growing demands.
In developing countries such as Ethiopia, textile production becomes their source of income that contributes to their gross domestic product GDP.
However, this has brought both consequences to such countries either in a positive way which is an improvement of economy or in a negative way which led to an increased anthropogenic impact on the biosphere. Heavy metals, particularly, Pb, Cr, Cd, and Cu are widely used for the production of color pigments of textile dyes.
These heavy metals which have transferred to the environment are highly toxic and can bioaccumulate in the human body aquatic life and natural water bodies and also possibly get trapped in the soil [ 1 ].
These toxic heavy metals entering in the aquatic environment are adsorbed onto particulate matter, although they can form free metal ions and soluble complexes that are available for uptake by biological organisms [ 2 ].
Various methods of treating effluents containing heavy metals have been developed over years, such as chemical precipitation, chemical oxidation or reduction, electrochemical treatment, ion exchange, reverse osmosis, filtration, evaporation recovery, and electrocoagulation [ 3 — 11 ].
These methods have significant disadvantages, including high energy requirements, inefficient metal removal, generation of toxic sludge, and expensive equipment. Therefore, there is a need to develop an efficient, rapid, cost-effectively and environment friendly method for the removal of heavy metals from effluents.
Adsorption of heavy metals is a new technology for treatment of textile effluents containing different types of heavy metals. Adsorption is the adhesion of a chemical substance adsorbate onto the surface of a solid adsorbent.
The most widely used adsorbent is activated carbon [ 12 ]. The adsorption process is being widely used by various researchers for the removal of heavy metals [ 13 — 18 ] from waste streams, and activated carbon has been frequently used as an adsorbent.
Adsorption isotherm is an empirical relationship used to predict how much solute can be adsorbed by activated carbon [ 19 ].
Adsorption isotherm is defined as a graphical representation showing the relationship between the amount adsorbed by a unit weight of adsorbent e. In this study a new, environment friendly, cost-effective, and locally available agrowaste Eragrostis tef adsorbent was investigated for the adsorption of heavy metals Cr, Cd, Pb, Ni, and Cu from textile effluents.
The effects of different parameters such as the pH, the initial metal concentration, the dose of the adsorption, the contact time, and temperature were studied. Materials and Methods 2. The factory is owned by Kebire Enterprises Plc. Adsorbent Teff straw was used as biomass sample in this study for adsorption of heavy metals from textile effluents.
It is indigenous to the country, and it is a fundamental part of the culture, tradition, and food. Recently, the taxonomy of Teff has been clarified by numerical taxonomy techniques, cytology, and biochemistry, including leaf flavonoids and seed protein electrophoretic patterns [ 21 — 23 ].
Figure 1 shows some samples of Teff straw before treatment and after treatment. Teff straw before treatment a and after treatment b. The CTS was treated with 1 M sulfuric acid at room temperature. The reacted product was washed repeatedly with distilled water.
Batch experiments were carried out to determine the adsorption isotherms of metal ions onto the adsorbents in mL glass flask.
The flasks were shaken at a constant rate, allowing sufficient time for adsorption equilibrium. It was assumed that the applied shaking speed allows all the surface area to come in contact with heavy metal ions over the course of the experiments.
The study was performed at room temperature to be representative of environmentally relevant condition. All experiments were carried out in duplicate and the average value was used for further calculation. The flasks were plugged and kept closed to avoid the fluctuation of pH due to the exchange of gases during the experiment.
The effects of various parameters on the rate of adsorption process were observed by varying contact time, adsorbent concentration, temperature, and pH of the solution. The solution volume was kept constant. Percent metal ion removal was calculated using the equation 2.Batch experiments were carried out to determine the adsorption isotherms of metal ions onto the adsorbents in mL glass flask.
The flasks were shaken at a constant rate, allowing sufficient time for adsorption equilibrium. A discussion main models on the spontaneous origin of life that aims to show how cellular complexity could have gradually emerged from simple systems – in contrast to the sudden appearance of complexity that creationists claim to have been necessary at the beginning of life.
Central issues like the composition of the early atmosphere of the Earth and the origin of the homochirality of amino. Removal of methylene blue by adsorption onto activated carbon developed from Ficus carica bast. bast (FCBAC). The experiments were carried out to explore methylene blue (MB) uptake by FCBAC.
The influence of various experimental factors such as contact time, initial dye concentration, adsorbent dosage, temperature and pH of dye . Chemistry Project Reports, Chemistry Projects CBSE | Sample MBA Project Reports, Free Download MBA/BBA Projects, Final Training Report, HR Projects MBA, Marketing Projects MBA, Operations Projects, Finance Projects MBA, MBA Project/Synopsis, Management Research | MBA BBA Projects in HR-Marketing-Finance and Mphil.
Abstract. The adsorption isotherms of CO 2, CO, N 2, CH 4, Ar, and H 2 on activated carbon and zeolite LiX were measured using a volumetric method.
Equilibrium experiments were conducted at , , and K and pressures up to MPa. The adsorption isotherm and heat of adsorption were analyzed for two pressure regions of experimental data: pressures up to MPa and up to MPa. Chromatography is a laboratory technique for the separation of a mixture.
The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at .