Kelarutan Lignin Kayu Cepat Tumbuh dalam Ekstraksi Alkali

The dissolution of wood lignin in the alkali solution were analyzed for two fast growing species, sengon (Paraserianthes falcataria) dan leda (Eucalyptus deglupta). Wood samples were extracted in 1% sodium hydroxide solution in cold and hot temperatures for 24 and 1 h, respectively. Extractable substances content, permanganate consumption (expressed as assumed lignin content) were analyzed from the filtrates, lignin content and diastereomeric of β-O-4 structure were analyzed from the wood residue after alkali extraction. The extracted substances from both of wood in hot alkali was higher than in cold alkali solution, although the time of cold alkali extraction was much longer that hot alkali extraction. Assumed lignin content in the extract was quite high in both samples which were 34.4-42.9% and 35.5-39.8% including 2,15-2,29% dan 1,04-1,32% of lignin for cold and hot alkali extraction, respectively. The changes in stereo isomeric form, erythro and threo, of β-O-4 structure of lignin in wood residue indicated that partial depolimerization of lignin was takec place during alkali treatment.

Potassium Permanganate and Chlorine Reactions with Natural Organic Compounds in Algerian Surface Water

The aim of this work is to study effect of two powerful oxidants (potassium permanganate and chlorine) on natural organic matter in surface waters. Trials are conducted out with three Algerian surface waters under controlled experimental conditions (oxidant dose applied and contact time). Permanganate was used alone in the first step, while the combination permanganate-chlorine was used in the second step.As for chlorine demand, permanganate consumption seems correlated with physicochemical characteristics of waters and particularly the nature and content of organic matter. The effect of a coupling preoxidation by permanganate / post-chlorination resulted in a decrease of chlorine consumption and amounts of produced trihalomethanes.

Pilot study on control of phytoplankton by zooplankton coupling with filter-feeding fish in surface water

A pilot-scale facility was originally designed to control phytoplankton in algae-laden reservoir water characterized by summer cyanobacteria blooms (mainly Microcystis flos-aquae). The system made good use of the different food habits of Daphnia magna and silver carp. Zooplankton (Daphnia magna), filter-feeding fish (silver carp), and zooplankton (Daphnia magna) were stocked in three separated tanks in sequence, respectively. Thus, single-cell phytoplankton and some Microcystis flos-aquae in small size were first grazed by Daphnia magna in the first tank, and in the second tank phytoplankton larger than 10 μm were filtered by silver carp, and the concentration of the remaining phytoplankton was further reduced to a rather low level by Daphnia magna in the third tank. The results showed that the system had good removal efficiencies of phytoplankton and chlorophyll a, 86.85% and 59.41%, respectively, and permanganate consumption (CODMn) and turbidity were lowered as well. A high phytoplankton removal efficiency and low cost indicated that the system had a good advantage in pre-treating algae-laden source water in drinking water works.

Total Organic Carbon as an Index for Specification of Water for Injection

Determination of organic compounds present as contaminants in purified water is of great importance. Total organic carbon (TOC) may be a useful parameter for evaluating the purity of water. This paper describes and compares the analytical results for solutions of 12 model compounds obtained by 3 methods: total organic carbon (TOC) analysis, determination of potassium permanganate consumption, and UV spectroscopy. TOC analysis gave values corresponding to the expected amounts of organic carbon for all the model compounds, whereas the other 2 methods gave highly variable results.