Dye wastes represent one of the most problematic groups of pollutants because they can be easily identified by the human eye and are not easily biodegradable. This literature review paper highlights and provides an overview of dye waste treatments performed over the three years period from 2008-2010. Noteworthy processes for the treatment of dye waste include biological treatment, catalytic oxidation, filtration, sorption process and combination treatments.
Lipase-catalyzed production of palm esters by alcoholysis of palm oil with oleyl alcohol in n-hexane was performed in 2L stirred-tank reactor (STR). Investigation on the performance of reactor operation was carried out in batch mode STR with single impeller mounted on the centrally located shaft. Rushton turbine (RT) impellers provide the highest reaction yield (95.8%) at lower agitation speed as compared to AL-hydrofoil (AL-H) and 2-bladed elephant ear (EE) impellers. Homogenous enzyme particles suspension was obtained at 250 rpm by using RT impeller. At higher impeller speed, the shear effect on the enzyme particles caused by agitation has decreased the reaction performance. Palm esters reaction mixture in STR follows Newtons' law due to the linear relation between the shear stress (tau) and shear rate (dupsilon/dy). High stability of Lipozyme RM IM was observed as shown by its ability to be repeatedly used to give high percentage yield (79%) of palm esters even after 15 cycles of reaction. The process was successfully scale-up to 75 L STR (50 L working volume) based on a constant impeller tip speed approach, which gave the yield of 97.2% after 5h reaction time.
The rapid growth of the human population and industrialization in the world has indirectly increased environmental problems such as water, air and land pollution. Amongst all, heavy metals can be considered as the most problematic pollutants. Numerous efforts have been attempted to minimize the impact of heavy metals. This chapter discusses the recent developments and technical applicability of different treatment methods for heavy metal removal. The adsorption process using various lowcost materials as the potential alternative for heavy metal removal is being highlighted and summarized.
Objective. To evaluate pharmacy students' perceptions of the educational value of reflective portfolio and to gain an understanding of the factors that might influence these perceptions. Methods. Bachelor of Pharmacy (BPharm) students' perceptions of using reflective portfolios were evaluated by administering the same questionnaire at the beginning of years 2, 3 and 4 of the curriculum. Statistical analysis was carried out to determine the differences among the perception scores of different academic years. Semi-structured interviews were completed with fourth-year students to further explore their experiences with the reflective portfolio. Students' deep information processing (DIP) skills were compared with those of students from another pharmacy cohort whose curriculum did not include a reflective portfolio. Results. The students' perceptions of the reflective portfolio improved significantly as they progressed from year 2 to year 4 of the curriculum. The factors that contributed to a positive experience were a clear understanding of objectives and guidelines for the reflective portfolio, useful mentor feedback, a positive learning attitude and motivation, and having a user-friendly technology platform for submission of the portfolio. The students' DIP skills after completing the reflective portfolio were higher than those of students who did not have a reflective portfolio assignment in their curriculum. Conclusion. Pharmacy students' appreciation of the educational value of a reflective portfolio increased as they progressed to their final year, and their DIP skills improved. These findings support the use of a reflective portfolio as a learning tool for BPharm students' personal and professional development.
Dyes are coloured substances that can be applied to various substrates such as textile materials, leather, paper and hair. The usage of dyes has continuously increased in many industries but the removal of this pollutant remains as a problematic issue as they are generally stable to light and oxidizing agents and are resistant to aerobic digestion. This literature review paper provides and lists several low cost adsorbents to serve as an alternative method for dye removal. Adsorption using low cost materials can be viewed as a sustainable treatment process because most of these materials are of naturally occurring, locally available and inexpensive materials. This paper covers an overview of dyes waste treatments for 5 years period, from 2008-2012. Some of the noteworthy adsorbents include agricultural byproducts, industrial waste and natural clay materials. Besides, the combination processes involving adsorption and other methods was also discussed.
Problem statement: Improper dye discharge from various industries such as textile, paper, cosmetic and plastics into receiving streams can be one of the sources towards water pollution. The release of these effluents not only causes various disruptions in the ecosystems, but also poses hazard effect as most of the dyes are highly toxic, mutagenic and carcinogenic in nature. Approach: To prepare an inexpensive and efficient sorbent by chemically modifying rice hull for the removal of Methylene Blue (MB) which is predominantly used in coloring acrylic fiber. Batch experiments were carried out for the removal of MB from aqueous solution by using Tartaric Acid Modified Rice Hull (TARH). Parameters studied include effect of pH, contact time, initial dye concentration and agitation rate and sorption isotherm. Results: From the results, the percentage uptake of MB increased with increasing contact time and agitation rate. Based on the linear regression correlation coefficient, R2, the system under study is more appropriately described by the pseudo-second order model. Maximum sorption capacity calculated from the Langmuir model is 25.0 mg g-1 for MB. Conclusion: The study has shown the effectiveness of TARH in the removal of MB, a basic dye from synthetic solutions
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