Preparation of activated carbon from pink guava (Psidium guajava) waste for the removal of methylene blue dye from aqueous solution / Nurulhuda Amri, Mohammad Syazwan Osman and Rasyidah Alrozi

Activated carbons are the most versatile and commonly used adsorbents because of their extremely high surface areas and micropore volumes, large adsorption capacities, fast adsorption kinetics and relative ease of regeneration. The most precursors used for the production of activated carbons are organic materials that are rich in carbon. In recent years, agricultural wastes has gained a significant interest among researches and being economic and eco-friendly due to their unique chemical composition, availability in abundance, renewable, low in cost and more efficient seem to be possible option for dye removal. Thus, the main objective of this research is to prepare activated carbon from pink guava waste (PGW) using simple thermochemical activation method. The raw material will be carbonized carbonized at temperature of 400°C for 1 h in a muffle furnace in order to produce char. Then, the char will be impregnated with sodium hydroxide (NaOH) at different impregnation ratios (1- 3) by weight followed by activation process at activation temperatures (400°C - 600°C) under different activation time (0.5 - 2 h). The optimize conditions for the preparation of activated carbon will be determined using Response Surface Methodology (RSM) with response to the activated carbon yield and percentage removal of methylene blue (MB) dye onto the adsorbent in order to obtain high adsorption capacity of the MB dye. The prepared pink guava seed based activated carbon (ACPGS) obtained by optimum conditions will be characterized through Brunauer Emmett Teller (BET) surface area, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) and Elemental Analyzer (EA). Then, the comparison on adsorption performance between ACPGW and commercial activated carbon (CAC) will be done using the batch adsorption study to determine the adsorption capacity for both adsorbents. The batch adsorption study will be carried out at different initial concentrations of methylene blue (50-500 mg/L) at room temperature (30°C) for 6 h. This research will explore the potential application of a low cost adsorbent to replace the commercial activated carbon for removal of dyes from wastewater

Biosynthesis and characterization of gold and silver nanoparticles by pink guava (psidium guajava) waste extract / Norashikin Ahmad Zamanhuri, Mohamed Syazwan Osman and Rasyidah Alrozi

There is an increasing commercial demand for nanoparticles due to their wide applicability in various areas such as electronics, catalysis, chemistry, energy and medicine. Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and give impact to the human health and environment. Metal nanostructures have unusual physicochemical properties and biological activities compared to their bulk parent materials. In this study, silver and gold nanoparticles (AgNPs and AuNPs) were synthesized from aqueous silver nitrate and auric acid solution respectively, through a simple and eco-friendly route using pink guava waste extract (PGWE) as reductant and stabilizer. The resulting silver and gold nanoparticles were characterized by using Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). AgNPs and AuNPs vary in size according to different amount of PGWE and silver nitrate and auric acid concentration used for the synthesis. Formation of AgNPs and AuNPs was confirmed by the color changed and by surface Plasmon spectra by using Uv-Vis spectrometer as well as absorbance peaks lie between 400 to 500 nm. The silver and gold nanoparticles obtained using this source have particles size in the range of 0- 50 nm. It was found that the increase in silver nitrate and uric acid concentration leads to the increasing size of AgNPs and AuNPs produced

Sustainable Treatment of Palm Oil Mill Effluent (POME) by using Pectin and Chitosan in Jar Test Protocol – Sequential Comparison

Oil palm industry in Malaysia is developing as demand towards alternative and cheaper edible oil continuously received from the European Union. However, adverse environmental impacts from this activity coupled with laden recalcitrant effluent contribute to the water pollution pose risk to water body and human’s health. The purpose of this research project is to compare the efficiency between Pectin (Heteropolysaccharide) and Chitosan (D-glucosamine) for tertiary treatment of anaerobic-aerobic treated palm oil mill effluent (POME). Factor that affecting the efficiency of the coagulation process such as dosage of coagulant used was studied by using jar-test protocol. From the experimental results, the ideal experimental conditions that remove turbidity, COD and colour were exceptional when using Chitosan. At this condition 83% of turbidity, 88% of TSS, 79% of colour and 53.1% of COD were removed. Nevertheless, it was observed that pH plays dominating factor that contribute to the overall removal efficiency. This research would give an idea on alternative way for tertiary wastewater treatment of POME

Preparation of chemically treated rambutan (Nepheuum lappaceum L.) peel for the removal of basic and reactive dyes from aqueous solution / Rasyidah Alrozi, Norashikin Ahmad Zamanhuri and Mohamed Syazwan Osman

Commercially available adsorbents are still considered expensive due to the use of non-renewable and relatively expensive starting material such as bituminous coal. Therefore, this study investigates the potential use of tropical fruit waste such as rambutan peel (RP) that available in Malaysia, as the precursor for the preparation of chemically treated adsorbent which can be applied for the removal of two types of dyes, which are basic Methylene Blue (MB) and reactive Remazol Brilliant Blue R (RBBR) from aqueous solution. Impregnation with hydrochloric acid (HCI) and sodium hydroxide (NaOH) was used in order to modify the surface characteristics of the prepared adsorbent. In this study, adsorption of MB and RBBR dye by NaOH-treated rambutan peels (N-RP) and HCI-treated rambutan peels (H-RP) were examined. The adsorption experiments were carried out under different conditions of initial concentration (25-500 mg/L), solution pH 2-12 and adsorbent dose (0.05-1.0 g). The influence of these parameters on the adsorption capacity was studied using the batch process. MB and RBBR adsorption uptake were found to increase with increase in initial concentration and contact time. The MB adsorption was unfavourable at pH4. Langmuir, Freundlich and Temkin isotherm models were used to illustrate the experimental isotherms and isotherms constant. The equilibrium data were best represented by Langmuir isothem model, showing maximum monolayer adsorption capacity of 231.34 and 112.69 mg/g for MB and RBBR dye, respectively. The rates of adsorption were found to obey the rules of pseudo-second order model with good correlation for both dyes. The result suggested that the N-RP and H-RP would be an excellent alternative for the removal of MB and RBBR dye by adsorption process

Electrochemical Removal of Copper Ion Using Coconut Shell Activated Carbon

In this work, coconut shell activated carbon (CSAC) electrode was evaluated to remove copper ion via electrochemical processes. CSAC electrode and graphite were applied as the cathode and the anode, respectively. The reusability of the electrode, the effects of initial pH, applied voltage and initial concentration were studied. The electrochemical process was carried out for 3 h of treatment time, and the electrodes (anode and cathode) were separated by 1 cm. The results revealed that CSAC is proven as a reusable electrode to remove copper ion, up to 99% of removal efficiency from an initial concentration of 50 ppm after it had been used three times. From the observation, the removal efficiency was optimum at an initial pH of 4.33 (without any initial pH adjustment). The applied voltage at 8 V showed a higher removal efficiency of copper ion compared to at 5 V

Sustainable Treatment of Palm Oil Mill Effluent (POME) by using Pectin and Chitosan in Jar Test Protocol – Sequential Comparison

Oil palm industry in Malaysia is developing as demand towards alternative and cheaper edible oil continuously received from the European Union. However, adverse environmental impacts from this activity coupled with laden recalcitrant effluent contribute to the water pollution pose risk to water body and human’s health. The purpose of this research project is to compare the efficiency between Pectin (Heteropolysaccharide) and Chitosan (D-glucosamine) for tertiary treatment of anaerobic-aerobic treated palm oil mill effluent (POME). Factor that affecting the efficiency of the coagulation process such as dosage of coagulant used was studied by using jar-test protocol. From the experimental results, the ideal experimental conditions that remove turbidity, COD and colour were exceptional when using Chitosan. At this condition 83% of turbidity, 88% of TSS, 79% of colour and 53.1% of COD were removed. Nevertheless, it was observed that pH plays dominating factor that contribute to the overall removal efficiency. This research would give an idea on alternative way for tertiary wastewater treatment of POME

Functional role of B-site substitution on the reactivity of CaMFeO3 (M = Cu, Mo, Co) perovskite catalysts in heterogeneous Fenton-like degradation of organic pollutant

peer reviewedBackground: Substitution of different types of B-site metal cations in the perovskite structure led to a significant change in the catalytic reactivity of the resulting catalysts. In this work, the functional role of B-site substitution on the catalytic reactivity of mixed oxides containing B-site substituted CaMFeO3 (M = Cu, Mo and Co) perovskite catalysts is investigated. Methods: The catalysts were synthesized via a modified EDTA-citric acid complexation method and tested for the heterogeneous Fenton-like reaction for oxidative degradation of acid orange II (AOII) dye in the presence of H2O2. Significant findings: CaCuFeO3 exhibited the highest AOII degradation (97%) followed by CaMoFeO3 (90%), CaFeO3 (64%) and CaCoFeO3 (40%) within 60 min of reaction, and the reaction followed a pseudo-second-order kinetics model. Interestingly, the partial substitution of Cu in the B-site of CaFeO3 enhanced the reaction rate constant achieving a k value of 1.9 × 10−2 L mg−1 min−1, approximately twenty-one times higher than that of the blank catalyst CaFeO3. The enhanced catalytic reactivity of CaCuFeO3 is associated with the high reducibility of copper/iron ions within the B-site structure in the presence of oxidant which facilitated fast redox cycling of the active sites during catalysis. The fast redox cycling is attributed to the decent electron mobility due to low electron transfer resistance between the active sites