Leaves Waste Research Articles

Biosorptive application of defatted Laurus nobilis leaves as a waste material for treatment of water contaminated with heavy metal

Defatted Laurus nobilis leaves as a natural biosorbent was first evaluated for elimination of toxic heavy metals such as Pb(II), Cd(II), Zn(II), Cu(II) from aqueous solutions for its wide availability as forest industry waste, in this study. The effects of solution pH, contact time, biosorbent dosage, initial metal ions concentration, ionic strength, humic acid effect, and their competitive effect on the biosorption of lead(II), cadmium(II), Copper(II), and zinc(II) by defatted Laurus nobilis leaves waste (LW) were studied for each metal. The biosorbent was characterized using FT-IR and SEM images. Comparative isotherm and kinetic studies were performed. The sorption of Cd(II) and Zn(II) on LW fitted better in the Freundlich model but Pb(II) and Cu(II) sorption fitted better in the Langmuir model. From the obtained results, the pseudo-second-order kinetic model described the biosorption of cadmium, lead, zinc copper ions the best. The biosorbent showed the maximum biosorption capacities (qm) of 96.2, 8.6, 8.7, and 6.0 mg g−1 for lead, cadmium, zinc, and copper, respectively. These results indicated that LW may be used as an effective and inexpensive heavy metal remediation material. Comparison to previous studies showed that LW is also comparable to (or better than) several other biosorbents.

Degradation of leaves and cellulose by Bacillus subtilis CL3 and Pseudomonas aeruginosa CL5 isolated from left waste dumps in Vietnam

The biodegradation capacity of two bacterial strains, Bacillus subtilis CL3 and Pseudomonas aeruginosa CL5, isolated from left waste dumps on thee different plant leaves were investigated. The leaves were derived from perennial plants, Malabar almond tree (Terminalia catappa), eucalyptus (Eucalyptus terticornis) and African mahogany (Khaya senegalensis). Among those 3 plants, Eucalyptus terticornis is known to be resistant for biodegradation in nature. In our study, B. subtilis CL3 could degrade a half of Eucalyptus terticornis leaves within 10 days. On the other hand, P. aeruginosa CL5 showed relatively poor degradation rate of the leaves of Eucalyptus terticornis, but could effectively degrade Khaya senegalensis and Terminalia catappa leaves than B. subtilis CL3. When these two bacteria strains were mixed, the degradation rates of all these types of leaves were enhanced. While B. subtilis CL3 could utilize 1,8-cineole, a component extracted from Eucalyptus terticornis, as a sole carbon source, this component inhibited the growth of P. aeruginosa CL5. The multiple and efficient left degradation capacities make these isolates good candidates for bioremediation of leaf waste and cellulose. Citation: Ha Danh Duc, 2017. Degradation of leaves and cellulose by Bacillus subtilis CL3 and Pseudomonas aeruginosa CL5 isolated from left waste dumps in Vietnam. Tap chi Sinh hoc, 39(4): 483-488. DOI: 10.15625/0866-7160/v39n4.10744.*Corresponding author: hadanhduc@gmail.comReceived 5 December 2016, accepted 12 December 2017

Zanimivosti iz Grčije v Strabonovem času

Strabon je Grčiji posvetil osmo in deveto knjigo svoje Geografije, v katerih je deželo izčrpno opisal. Večji del njegovega besedila se sicer bere kot ‘Grčija nekoč’, opisuje jo predvsem v luči tega, kar pravi Homer, vendar pa navaja tudi nekaj podatkov, ki se nanašajo na njegovo dobo. Ti predstavljajo majhen odstotek vsebine, nekaj več se jih nanaša le na Sparto, Korint in Tespije; v članku so zbrani in komentirani. Sliko tedanje, namreč avgustejske Grčije pa dopolnjujejo latinski in grški napisi, ki osvetljujejo življenje Grkov pod rimsko oblastjo in v sožitju z rimskimi institucijami, kolonijami ter italskimi in rimskimi priseljenci, ki so živeli v večini večjih grških mest. V članku je navedenih le nekaj najbolj značilnih.

Acid Mine Drainage Requires NPDES Permit

East Bay Municipal Utility District and the California Regional Water Quality Control Board owned and operated the Penn Mine facility, which was the site of an abandoned copper and zinc mine that operated intermittently from the 1860s through the 1950s. Mining companies had left waste that formed “acid mine drainage” when exposed to oxygen and rain. The drainage, which had high concentrations of chemicals including sulfuric acid and cadmium, was carried downhill into the Mokelumne River. To reduce the threat of continued toxic runoff, the defendants built a facility to capture contaminated surface water. Occasionally water and drainage that had collected in the reservoir passed into the river and a reservoir. An environmental group brought this action, alleging that the facility discharged pollutants without a National Pollution Discharge Elimination System (NPDES) permit. The trial court found for the group.