Commercial activated carbon has been a preferred adsorbent for the removal of various pollutants, and its widespread use is restricted due to its relatively high costs, which led to the researches on the possible alternative nonconventional and low-cost adsorbents. The use of agricultural products and by-products for instance has been widely investigated as a replacement for the current costly methods of removing various pollutants. In this critical review, an extensive list of the production of activated carbon from oil palm biomass is presented. The effects of various process parameters on the pyrolysis stage, characteristics, and influences of physical and chemical activating conditions on the production of activated carbons from oil palm biomass are discussed. A comparison in characteristics and applications of activated carbons from oil palm biomass with commercial activated carbons is made. It is evident from a literature survey of about 200 recently published articles that activated carbons from oil palm biomass exhibit outstanding capabilities for removal of various pollutants.
A huge amount of wastewater released from industries flow into different water resources such as rivers. Industrial effluents can be regarded as an important resource for water, nutrients and energy. Microbial fuel cell (MFC), a green eco-friendly approach can be applied for the treatment of wastewater with electricity generation concomitantly. It is a novel strategy to generate clean, renewable, safe green energy to maintain a clean environment. MFC technology can be used for effluent treatment, biochemical oxygen demand and chemical oxygen demand elimination, sulphate and removal of toxic metal and denitrification. MFC has an advantage as compared with other wastewater treatment methods because of certain unique properties such as energy and economic benefits, less effect on the environment and high stability. However, the operation of MFCs also has multiple setbacks such as short life span, high cost, membrane fouling and so on. MFC technology shows a pivotal function in solving problems of energy crisis and waste management. This chapter describes current applications of MFC technology for the treatment of industrial effluents with cost-effective energy generation and covers the gap by highlighting key future research areas to improve its performance.
Ammonia nitrogen (NH 3 /NH 4 + ) polluted wastewater raises a serious threat to the safety of aquatic system. In addition to eutrophication, the presence of NH 3 /NH 4 + in the aquatic body reduces chlorine disinfectant efficiency during water treatment. Concerns regarding other conventional NH 3 -N removal processes, to tackle these contaminants, advanced oxidation processes (AOPs) have been applied to remove ammonia nitrogen. The AOPs utilizes hydroxyl radical (•OH) for oxidation and have received considerable attention during the last few years in wastewater treatment, research technologies, and development. These processes are used to gradually reduce ammonia nitrogen to innocuous products with the help of high reactivity of hydroxyl radicals. In this chapter, a systematic study is carried out with the focus on the effects of ammonia nitrogen on the growth, physiology, biochemistry, and immune response of aquatic species. Moreover, experimentations and working procedures that can be used to remove ammonia nitrogen by AOP application are been discussed. This chapter also reviews recent findings and observations for the removal of ammonia nitrogen by photocatalysis and ozonation techniques and provide some recommendations for future research works.
In this study, the leaves of Licuala spinosa were used to determine the total phenolic and flavonoid content as well as antioxidant activity of different crude extracts. The samples were extracted successively with organic solvents such as hexane, chloroform and ethyl acetate respectively. The total phenolic content was determined by Folin-Ciocalteu’s assay. Chloroformcrude extract showed the highest total phenolic content (9.42± 0.06 mg GAE/g), followed by ethylacetate crude extract (8.91± 0.06 mg GAE/g) and hexane crude extract (6.78±0.26 mg GAE/g).The total flavonoid content was determined by Aluminium chloride colometric assay and expressedas QE equivalent. Chloroform crude extract showed the highest total flavonoid content (8.96 ± 0.21mg QE/g), followed by ethyl acetate crude extract (7.04 ± 0.02 mg QE/g) and hexane crude extract(3.05 ± 0.09 mg QE/g). The antioxidant activity of extracts were evaluated by 2,2-diphenyl-1-picyhydrazyl (DPPH) assay. In DPPH assay, IC50 values were used to determine the antioxidant potential of the sample. The lower the IC50 value, the higher the antioxidative property. Among allthe extracts, chloroform extracts exhibited higher DPPH radical scavenging activity with IC50 value of 0.032 mg /mL. BHT used as the positive control showed IC50 value of 0.089 mg/mL
The need for energy resources is growing all the time, which means that more fossil fuels are needed to provide them. People prefer to consume chicken as a source of protein, and this creates an abundance of waste. Thus, microbial fuel cells represent a new technological approach with the potential to generate electricity through the action of electrogenic bacteria toward chicken manure, while reducing the abundance of chicken manure. This study investigated the effect of different pretreatment (thermal, alkaline, and sonication pretreatment) of chicken manure to improve the performance of a membrane-less microbial fuel cell (ML-MFC). Statistical response surface methodology (RSM) through a central composite design (CCD) under a quadratic model was conducted for optimization of the ML-MFC performance focusing on the COD removal efficiency (R2 = 0.8917), biomass (R2 = 0.9101), and power density response (R2 = 0.8794). The study demonstrated that the highest COD removal (80.68%), biomass (7.8539 mg/L), and power density (220 mW/m2) were obtained when the pretreatment conditions were 140 °C, 20 kHz, and pH 10. The polarization curve of the best condition of ML-MFC was plotted to classify the behavior of the ML-MFC. The kinetic growth of Bacillus subtillis (BS) showed that, in treated chicken manure, the specific growth rate µ = 0.20 h−1 and doubling time Td = 3.43 h, whereas, in untreated chicken manure, µ = 0.11 h−1 and Td = 6.08.
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