Muhammad Ridwan Fahmi

Performance evaluation of okra (abelmoschus esculentus) as coagulant for turbidity removal in water treatment

The objective of this study is to evaluate the performance of turbidity removal in water by using Okra (Abelmoschus esculentus) as natural coagulant. The coagulation active agent in various Okra sections was extracted with distilled water and NaCl 1.0 M solutions. Synthetic water containing kaolin with turbidity of 55 NTU was used as water source in this study. The result shows that Okra seed that extracted both with distilled water and NaCl 1.0 N solution has the potential advantage as natural coagulant for turbidity removal in comparison with other sections of the plant. However, the seed is not economically feasible to be used as coagulant. The dried Okras leaf that commonly considered as waste material could be proposed as an alternative coagulant in water treatment process, due to its similarity in coagulation behaviour with Okras seed. FTIR analysis on leaf shows that chemical functional groups in protein were significantly removed after extraction with distilled water and NaCl 1.0 N solution. The result indicated a strong correlation between the protein content and turbidity removal efficiency, which eventually suggest that the protein in Okra could potentially be an active agent in coagulation process.

Physicochemical properties of pyrolitic carbon black from waste tyres

Waste tyres which are mainly generated from automotive industries have become a major environmental problem to the local authorities, the tyre industries and tyre dealer. When tyres are no longer usable due to worn-out, defect or service failure they are usually dumped in the landfill sites. Pyrolysis is a process of the thermal decomposition of waste tyres in the absence of air and the oxygen. Pyrolysis may be an environmentally friendly process to transforms used tyres into gas, oil, steel and carbon black waste. The rate of recovery is 45 wt % for fuel, 30 wt % for carbon black and 10 wt % for steel wires for each end-of-life tyres. In this paper, the potential use of pyrolised carbon black generated from pyrolysis process of waste tyres is investigated. From the physical analysis of this carbon black waste, it was observed that there is various refraction particles sizes from the sieve test and different morphologies gathered from SEM analysis. Moreover, X-Ray Fluorescence (XRF) and TGA/DTG analysis on the carbon black waste showed high content of inorganic additives such as Silica (Si), Calcium (Ca) and Iron (Fe) which contaminate the sample. The carbon black waste started to decompose at a lower temperature of 480°C to 680°C compared to standard black at 500°C to 740°C. The test results gathered in this paper will act as a base-line towards alternative material or to replace the commercial carbon black available in the market.

Kesan gabungan aktiviti guna tanah dan perubahan musim terhadap kualiti sumber air: kajian kes di Terusan Utara, Kedah

Suatu kajian untuk menilai kesan gabungan aktiviti guna tanah dan perubahan musim terhadap kualiti sumber air telah dijalankan di Terusan Utara, Kedah. Kajian ini dijalankan di lima stesen terpilih selama 12 bulan berdasarkan Indeks Kualiti Air (WQI) dan Piawaian Interim Kualiti Air Kebangsaan (INWQS). Kajian mendapati kualiti air di Terusan Utara berada pada Kelas III dan berlaku peningkatan kualiti air dari hulu ke hilir. Hampir semua stesen berpotensi sebagai punca pencemaran berdasarkan aktiviti guna tanah terutamanya di Pelubang, Jitra serta Tunjang. Kajian menunjukkan terdapat perbezaan yang signifikan ketika perubahan musim pada DO, TSS serta BOD, namun tidak pada ammonia, pH dan COD. Secara amnya, kombinasi aktiviti guna tanah dan perubahan musim boleh mempengaruhi atau memberi kesan terhadap kualiti sumber air. Oleh itu, tindakan segera perlu dilakukan untuk mengawal punca pencemaran bagi memastikan kualiti sumber air di Terusan Utara kekal terpelihara.

Adsorption of Reactive Red 120 by Using Regenerated Spent Carbon

In this study the performance of regenerated spent carbon for azo dye removal was evaluated in batch and continuous column. The spent carbon was generated by thermal method through pyrolysis process and chemical method by using NaOH 6.0 M solution. Reactive Red 120 (RR120) was selected as a model of azo dye due to its common application in the industries. The regeneration of spent granular activated carbon (GAC) by pyrolysis could produce adsorbent that has the adsorption capacity closer to new GAC. The result indicated that paralysed GAC could potentially apply to replace new GAC for RR120 adsorption. In addition, the continuous adsorption operation in mini column test confirmed that the order of adsorption capacity of each GAC is as follows: new GAC, pirolysed GAC, chemical treated GAC and spent GAC.

Raman Scattering Characterization of MoxW1-xS2 Layered Mixed Crystals

A systematic study of a series of MoxW1-xS2 layered mixed crystals, with 0 ≥ x ≤ 1, grown by the chemical vapor transport method were carried out by using Raman scattering measurements. The peaks of the two dominant first-order Raman-active modes, A1g and E2g1 , and several second-order bands have been observed in the range of 150-500 cm-1. The peaks corresponding to A1g mode show one-mode type behavior while the peaks of E2g1 mode demonstrate two-mode type behavior for the entire series. The results can be explained on the basis of the atomic displacements for each mode. For A1g mode only sulfur atoms vibrate and this give rise to a one-mode type behavior for the mixed crystals. For E2g1 mode metal atoms also vibrate as well as sulfur atoms, the mass difference of the vibrating Mo and W cations causes the two-mode type behavior of E2g1 mode. In addition, the observation of largest asymmetry and broadening of A1g mode for Mo0.5W0.5S2 has been attributed to random alloy scattering.

Degradation characteristic of monoazo, diazo and anthraquinone dye by UV/H2O2 process

In this study, the degradation characteristic of monoazo, diazo and anthraquinone dye by UV/H2O2 process was evaluated based on the trend of color, chemical oxygen demand (COD) and total organic carbon (TOC) removal. Three types of dyes consist of monoazo, diazo and anthraquinone dyes were used to compare the degradation mechanism of the dyes. The UV/H2O2 experiments were conducted in a laboratory scale cylindrical glass reactor operated in semi-batch mode. The UV/Vis characterization of monoazo, diazo and anthraquinone dye indicated that the rapid degradation of the dyes by UV/H2O2 process is meaningful with respect to decolourization, as a result of the azo bonds and substitute antraquinone chromophore degradation. However, this process is not efficient for aromatic amines removal. The monoazo MO was difficult to be decolorized than diazo RR120 dye, which imply that number of sulphonic groups in the dye molecules determines the reactivity with hydroxyl radical. The increased in COD removal is the eviden...