Elucidation of adsorption mechanisms and mass transfer controlling resistances during single and binary adsorption of caffeic and chlorogenic acids

Environmental Science and Pollution Research - In this work, the potential of activated carbon to remove caffeic and chlorogenic acids in aqueous solution was investigated. The study focused on...     

Investigation of physico-chemical properties and microbial community during poultry manure cocomposting process

Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2:1 (V/V) for a period of 60 days. An investigation was carried out to study the extracellular enzymatic activities and structural degradation utilizing Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The microbial succession was also determined by using denaturing gel gradient electrophoresis (DGGE). The compost was able to reach its highest temperature of 71 ℃ at day 3 and stabilized between 30 and 40 ℃ for 8 weeks. CMCase, FPase and β-glucosidase acted synergistically in order to degrade the cellulosic substrate. The xylanase activities increased gradually during the composting and reached the peak value of 11.637 U/g on day 35, followed by a sharp decline. Both LiP and MnP activities reached their peak values on day 35 with 0.431 and 0.132 U/g respectively. The FT-IR spectra revealed an increase in aromaticity and a decrease in aliphatic compounds such as carbohydrates as decomposition proceeded. TGA/DTG data exhibited significant changes in weight loss in compost samples, indicating degradation of organic matter. SEM micrographs showed higher amounts of parenchyma exposed on the surface of rubber wood sawdust at day 60, showing significant degradation. DGGE and 16S rDNA analyses showed that Burkholderia sp., Pandoraea sp., and Pseudomonas sp. were present throughout the composting process. Ornithinibacillus sp. and Castellaniella ginsengisoli were only found in the initial stage of the composting, while different strains of Burkholderia sp. also occurred in the later stage of composting.     

Cover Image

The cover image is based on the Original Article Noninvasive prenatal paternity testing by means of SNP-based targeted sequencing by Jacqueline Chor Wing Tam et al., https://doi.org/10.1002/pd.5595 .

     

Evaluation of the mutagenic potential of some compounds using Salmonella typhimurium

The mutagenicity of sodium nitrite, potassium chromate, O-tolidine, and smoke condensate from tobacco was shown on Salmonella typhimurium TA 1535. Sodium nitrite was definitely mutagenic on TA 1535 without S-9 mix. Potassium chromate without S-9 mix was also mutagenic on TA 1535. However, addition of S-9 mix resulted in a complete loss of potassium chromate mutagenicity. O-tolidine with and without S-9 mix elicited a very weak and variable mutagenic effect for strain TA 1535. Smoke condensate from pipe tobacco without S-9 mix elicited a weak mutagenic effect, whereas with S-9 mix it showed no mutagenicity on TA 1535.     

Development of prolonged standing strain index to quantify risk levels of standing jobs

Many occupations in industry such as metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture for a long time. Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs. This study developed the prolonged standing strain index (PSSI) to quantify the risk levels caused by standing jobs, and proposed recommendations to minimize the risk levels. Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and indoor air quality, were the basis for developing the PSSI. All risk factors were assigned multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness. multipliers, and the PSSI was the product of those multipliers. Recommendations for improvement are based on the PSSI; however, extensive studies are required to validate their effectiveness.     

Phytoremediation of heavy metals: mechanisms,methods and enhancements

Polluted soil and water impact the quality of food and nutrients of human and animal biota. Soil and water are mainly polluted by effluent discharges from industries, which are broadly classified into metallic and nonmetallic pollutant-bearing effluents. In order to tackle this problem, a plant-based technology called phytoremediation is used to clean contaminated lands. Phytoremediation is based upon several processes such as phytodegradation, phytovolatilization, phytoaccumulation and phytoextraction. These methods are efficient, eco-friendly and economic. This paper reviews the methods and mechanisms involved in phytoremediation of heavy metals, and enhancement processes.     

Allozyme polymorphisms and heavy metal levels in the green-lipped mussel Perna viridis (Linnaeus) collected from contaminated and uncontaminated sites in Malaysia

It has been widely reported that heavy metal contamination in coastal waters can modify the allozyme profiles of marine organisms. Previous studies have recorded elevated metal concentrations in sediments and mussel tissues off Peninsular Malaysia. In the present study, horizontal starch gel electrophoresis was carried out to estimate the levels of allelic variation of the green-lipped mussel, Perna viridis, collected from one contaminated and three relatively uncontaminated sites off Peninsular Malaysia. Fourteen polymorphic loci were observed. In addition, the concentrations of cadmium, copper, lead, mercury and zinc were determined in the sediments and in the soft tissues of the mussels. Mussels from contaminated site, evidenced by high metal pollution indices (MPI) of the sediment and the mussel tissues, showed the highest percentage of polymorphic loci (78.6%), while those collected from the uncontaminated sites had lower MPI of the sediment and mussel tissue, and exhibited lower percentages of polymorphic loci (35.7-57.1%). The population from the contaminated site showed the highest excess of heterozygosity (0.289) when compared to that of the populations from the three uncontaminated sites (0.108-0.149). Allozyme frequencies at the phosphoglucomutase (PGM; E.C. 2.7.5.1) locus also differed between the contaminated and uncontaminated populations. Previous studies have shown that exposure to heavy metals can select or counter-select for particular alleles at this locus. The present results suggest that allozyme polymorphism in P. viridis is a potential biomonitoring tool for heavy metal contamination but further validation is required.     

Cobalt and zinc removal from aqueous solution by chemically treated bentonite

Natural bentonite was treated by hydrochloric, nitric, and phosphoric acids followed by washing with sodium hydroxide in order to enhance its adsorption capacity. The sample that treated with hydrochloric acid followed by further treatment with NaOH showed the highest cation exchange capacity with a value of 51.20 meq/100 g. The zero-point of charge for this sample was found to be 4.50. Adsorption isotherms for both cobalt and zinc were fitted using Langmuir, Freundlich, and Redlich-Peterson and showed an adsorption capacity of 138.1 mg Co²⁺ and 202.6 mg Zn²⁺ per gram of treated sample.