Removal of Cr 3+ by electrocoagulation from simulated wastewater

Trivalent chromium (Cr3+) removal from aqueous solution  by electrocoagulation using iron electrodes material was investigated in this paper. Effects of current density, initial concentration of Cr 3+, operating time,  pH, electrode distance, and operating cost have been investigated. At higher current density and solution pH, remarkable removal of Cr3+ was observed. Experiments have been show that the maximum removal percentage of the Cr3+ 99.89 % was at initial concentration 1000mg/L,  current density 9.34mA/cm2 and reaction time 1 hours. Energy consumption was calculated  for Cr3+ removal at different time. The method is observed to be very effective in the removal Cr3+ ion from aqueous solution. Electrocoagulation process need simple equipment, designable any size, use any chemical substances and low operating cost.DOI: http://doi.dx.org/10.5564/mjc.v15i0.330 Mongolian Journal of Chemistry 15 (41), 2014, p89-9

Mongolian Herders’ Evaluation of Rangeland Ecosystems Services, Values, and Changes over the Past Decade

Mongolia\u27s rangeland is one of the largest remaining contiguous ecosystems encompassing 2.6% of the global grasslands, and almost three-fourths of the country\u27s territory provides essential ecosystem services (ESS) for over 3 million Mongolians and 71 million livestock. The well-being of 171,605 pastoral households directly depends on the rangelands receiving provisional services in the forms of nutrition, material use and energy, regulatory services, and cultural services. This study explored herders\u27 perceptions of these ESS, their evaluation for ESS values, and observations of ESS change for the last decade. The study found that Mongolian herders have more benefits from provisional ESS (on average, 10 out of 18 identified), including nutritional and material use (four out of six and nine respectively), and energy services (two types out of three). An average herder household said to receive eight types of regulatory services out of 10, including environment regulation, storage/sequestration, erosion control, disease, and pest control, flood and wind protection, water cycle, soil formation and climate regulation, and six cultural services out of seven such as experiential and intellectual interactions with nature, historical and cultural heritage, both symbolic and religious-spiritual customs and nomadic identity and pride. The herders most valued the provisioning services, followed by regulatory services, and reported a declining trend in provisioning ESS for the past decade, while, in their views, non-provisioning services remained the same. Herders\u27 reported about the exploitation of local ecosystems by external companies without sharing benefits with pastoral communities and contributing to the ESS restoration and maintenance, which was the expression of the common rangeland marginalization narrative. The study recommends necessary policies and actions to ensure equitable benefit distribution derived from rangelands to support adaptive capacity and well-being of pastoral communities, essentially acknowledge the importance of non-provisional ESS across various levels

Characterization of Alkali Activated Materials Prepared from Continuous Attrition and Ball Milled Fly Ashes

Mechanical activation is known to greatly influence the reactivity of fly ashes. In this paper, we report a comparative study of the properties of alkali-activated geopolymer materials prepared using both ball-milled and attrition-milled fly ashes. Ball milling was carried out for 30 min and 60 min while attrition milling was carried out continuously in a high-speed attritor. The surface area of the raw fly ash decreased from 4017 cm2/g to 3999 cm2/g and 3912 cm2/g after ball milling for 30 min and 60 min, respectively. By contrast, the surface area of the continuously attrition-milled fly ash increased to 5545 cm2/g. Fly ash processed by continuous attrition milling showed a 50% particle size reduction to 25–38 μm, whereas fly ash ball-milled for 30 and 60 min was reduced in size by 33.4 and 42.9%. The milled fly ash samples were activated with 8 M NaOH solution and cured at 40 °C for 68 h. After curing, the samples were maintained at room temperature, and their 7-, 14-, and 28-day compressive strengths were measured. The compressive strength of the attrition-milled 28-day geopolymer paste was 24.6 MPa; that of the geopolymers ball-milled for 30 and 60 min was 23.37 MPa and 17.58 MPa, respectively; and that of the unmilled control geopolymer fly-ash-based paste was 17 MPa. The improvement in the mechanical properties is attributed to the increased gel formation resulting from the increased surface area (decreased particle size) in the fly ash glass starting material

High life satisfaction reported among small-scale societies with low incomes

Global polls have shown that people in high-income countries generally report being more satisfied with their lives than people in low-income countries. The persistence of this correlation, and its similarity to correlations between income and life satisfaction within countries, could lead to the impression that high levels of life satisfaction can only be achieved in wealthy societies. However, global polls have typically overlooked small-scale, nonindustrialized societies, which can provide an alternative test of the consistency of this relationship. Here, we present results from a survey of 2,966 members of Indigenous Peoples and local communities among 19 globally distributed sites. We find that high average levels of life satisfaction, comparable to those of wealthy countries, are reported for numerous populations that have very low monetary incomes. Our results are consistent with the notion that human societies can support very satisfying lives for their members without necessarily requiring high degrees of monetary wealth.Peer reviewe

Indigenous Peoples and local communities report ongoing and widespread climate change impacts on local social-ecological systems

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