Selective emulsion liquid membrane extraction of silver from photographic waste industries

The field of liquid membrane technology is currently undergoing a rapid expansion in research as well as its application as an industrial separation process. Liquid membrane can be manipulated to selectively separate a specific solute from a mixture and even to extract a solute against its concentration gradient. A liquid membrane system comprises of three liquid phases; feed phase, liquid membrane organic phase and receiving phase. Liquid membrane can be prepared using support or as emulsion (unsupported) liquid membrane. Emulsion liquid membrane is a liquid membrane in which the membrane phase of an emulsion is dispersed into the feed phase to be treated. This method was investigated as an alternative process for the recovery of silver from photographic waste, which contains various metals ions such as silver, iron, sodium and potassium. The important parameters governing the extraction process of silver such as agitation speed, homogenizer speed, surfactant and carrier concentrations, type of diluents, treat ratio and types of stripping solution were investigated. This process has been conducted in a batch system using a mixer-settler. The results show that the mobile carrier Cyanex 302 is selective towards silver and almost completely extract silver over the other metals that existed in the photographic waste. The optimum silver extraction was obtained by using 0.03 M Cyanex 302, 3 % (w/v) Span 80, 250 rpm stirring speed, 1.0 M thiourea in 1.0 M H2SO4 stripping agent, 1:5 of treat ratio, and kerosene as a diluents. The experimental result also shows that the emulsion liquid membrane system could be recycled twice having 80% of silver was extracted. In addition, theoretical studies show that the developed model could predict the extraction performance of the system understudied as obtained from experimental data

Cultivation of pleurotus ostreatus on oil palm fronds mixed with rubber tree sawdust

Pleurotus ostreatus (oyster mushroom) is cultivated in Malaysia using rubber tree sawdust (RS). Due to a shortage and the increasing cost of rubber tree sawdust, an alternative substrate is needed. This study was undertaken to evaluate the feasibility of oil palm frond (OPF) as an alternative substrate for the cultivation of Pleurotus ostreatus. The OPF and RS were analysed for their elemental compositions. The mycelium growth rate, the time for first pinhead formation and first fruiting bodies, yield, and biological efficiency (BE%) were studied for 100 % OPF, 90 % OPF - 10 % RS, 70 % OPF - 30 % RS, 50 %OPF - 50 % RS, 30 % OPF - 70 % RS, 10 % OPF - 90 % RS and 0 % OPF - 100 % RS substrates supplemented with rice bran and calcium carbonate. The proximate nutritional value of Pleurotus ostreatus first flush was also analysed for 100 % RS and 100% OPF. For mycelium growth rate, time for first pinhead formation and time to first Pleurotus ostreatus crop, the 0% OPF - 100 % RS substrate recorded the shortest time followed by the 10% OPF -90 % RS substrate. The 0 % OPF - 100 % RS substrate gave the highest yield of 135 g (22.6 % BE) whereas 125 g (20.9 % BE) was obtained from the 30 % OPF - 70 % RS substrate. The first flush of Pleurotus ostreatus harvested from the 100 % OPF substrate was richer in protein but lower in fat and carbohydrate compared to the mushrooms from the 100 % RS substrate making it an excellent food for low caloric diet, but OPF alone is not suitable as an alternative substrate for the cultivation of Pleurotus ostreatus as it took a longer growth performance with a lower yield of fruiting bodies compared to RS substrate

A Short Review on Recent Development of Laccase Immobilization on Different Support Materials

Laccase is a bio catalytic agent and multi-copper enzyme containing oxidases that are potentially great for oxidizing large number of phenolic and non-phenolic compounds. However, drawbacks do arise when laccase use in large scale; low in stability, high production cost, non-reusability, sensitive towards denaturing and poor storage ability of free enzymes. These problems lead to the progress in laccase immobilization in order to facilitate the efficient recovery and re-use of the enzyme, thus enabling cost-effective in continuous processes. Apart from discussing on different methods in laccase immobilization such as entrapment, encapsulation and cross-linking in general, we have reviewed a recent development in laccase immobilization on different supports or carriers binding (natural and synthetic). Future works are recommended to focus on innovative strategies on the modified supports to improve the enzyme immobilization as well as sensible entrapment techniques for industrial applications

Issues and management for used disposable diapers in solid waste in the city of Kuala Lumpur

Disposable diapers are indispensable in modern societies. Disposing of soiled diapers is a major global environmental problem as they constitute a large percentage of the municipal solid waste. Kuala Lumpur has a population of 1.79 million in an area of just 243 km2. Currently, Kuala Lumpur’s municipal solid waste generation is about 3.500 tonnes per day where it is sent 80 km away to Tagar Sanitary Landfill for disposal through Taman Beringin Transfer Station which has a capacity of 1,700 tonnes per day. Waste characteristics study conducted in April 2016 showed baby disposable diapers contributed to 14.35 weight %, the fourth main composition after food and organics waste (32%), plastics (25%) and paper (17%). Comprehensive sampling conducted in 2001/2002 and 2014 showed the average diapers content was about 5.14 and 10.68 % weight, respectively. This paper looks at the issues of used baby diapers in solid waste, the options for its disposal worldwide such as landfilling, composting, recycling and incinerating with energy generation and then selecting the most sustainable, practical, effective and efficient disposal option for Kuala Lumpur

Facile synthesis of polyethylenimine-modified sugarcane bagasse adsorbent for removal of anionic dye in aqueous solution

Many studies have reported that surface modification of various type of materials by using polyethylenimine (PEI), usually necessitate to be combined with the crosslinkers, namely glutaradehyde, sodium tripolyphosphate, etc. The sugarcane bagasse (SB) is a fibrous agricultural waste derived from sugarcane stalks residue which has rich-cellulose content that makes it amenable to surface functionalization for tailored application. Thus, it is possible for SB material to modify by using solely PEI and eliminate crosslinking step. In this study, SB was used as supporting material for modified PEI to produce polyethylenimine-modified sugarcane bagasse (PmSB) for the adsorption of Reactive Black 5 (RB5) dyes from aqueous solution. The effects of contact time (60 – 300 min), adsorbent dosage (0.05 – 0.15 g); initial dye concentration (0.01 – 0.10 g/L), pH (5 - 9) and temperature (30 – 70 °C) were varied to evaluate the performance of the PSB under different experimental conditions. The kinetics study revealed that the adsorption experimental data fitted the pseudo second order model. The equilibrium adsorption data also fitted the Langmuir model with R2 of 0.99 and maximum monolayer capacity of 25 mg/g. The thermodynamic parameters suggest that the RB5 dye adsorption by PEI modified SB was spontaneous, exothermic and exhibited chemisorption. The adsorbent can be regenerated up to 4 cycles with the percentage dye removal greater than 80%). Therefore, the PmBS adsorbent has proven that the PEI is solely sufficient as modifying agents for SB material, even without an assistance of crosslinker reagents for removal of RB5 dye in aqueous solution

Introduction to separation processes

King (1980) define separation processes as those operations which transform a mixture of substances into two or more products which differ from each other in composition. These may involve either removing a single component from a mixture or separating a solution into its almost pure components. This is achieved by exploiting molecular, thermodynamic, and transport properties differences between the species in the different phases

The effects of mass transfer on drop breakage in rotating disc contactors

Breakage of single drops of solvent in water is examined in a 300 mm diameter RDC. Correlations for drop size distribution and scale up effects obtained from breakage without mass transfer are used to find apparent interfacial tensions for breakage with mass transfer occurring

Applications of solvent extraction: A summary

This paper summaries the processes involved in solvent extraction plus its various applications in the organic and inorganic chemical industries

Pencemaran bunyi trafik di sekitar kawasan persekolahan

Kajian untuk menilai tahap pencemaran bunyi bising daripada trafik di sekitar salah sebuah sekolah di Senai telah dijalankan. Pengukuran bunyi bising dibuat menggunakan meter aras bunyi dan diukur dalam Skala unit desibels (dB). Hasil kajian menunjukkan bahawa tahap bunyi bising yang sampai ke dalam kelas yang paling hampir dengan lebuhraya adalah di antara 53-57 dB(A). Keadaan ini boleh menyebabkan proses pembelajaran di dalam kelas tersebut terganggu. Ianya juga memaksa guru-guru yang mengajar meninggikan suara mereka bagi membolehkan semua pelajar di dalam kelas dapat mendengar dengan jelas apa yang diajar

Application of reverse osmosis in food processing

Reverse osmosis is only recently used in the food industry and is gaining interest. This article treats the various effects of the physical properties of food towards the permeation flux of water, the apparatus used together with methods of improving their performance. Lastly, a study of the concentration of whey and milk is include