Removal of copper from water using limestone filtration technique. Determination of mechanism of removal

This paper discusses heavy metal removal from wastewater by batch study and filtration technique through low-cost coarse media. Batch study has indicated that more than 90% copper (Cu) with concentration up to 50 mg/l could be removed from the solution with limestone quantity above 20 ml (equivalent to 56 g), which indicates the importance of limestone media in the removal process. This indicates that the removal of Cu is influenced by the media and not solely by the pH. Batch experiments using limestone and activated carbon indicate that both limestone and activated carbon had similar metal-removal efficiency (about 95%). Results of the laboratory-scale filtration technique using limestone particles indicated that above 90% removal of Cu was achieved at retention time of 2.31 h, surface-loading rate of 4.07 m3/m2 per day and Cu loading of 0.02 kg/m3 per day. Analyses of the limestone media after filtration indicated that adsorption and absorption processes were among the mechanisms involved in the removal processes. This study indicated that limestone can be used as an alternative to replace activated carbon.     

Effect of using limestone fines on the chemical shrinkage of pastes and mortars

Environmental Science and Pollution Research - The main aim of this study is to examine the effect of incorporating limestone fine (LF) on chemical shrinkage of pastes and mortars. For this...     

Carbon nanotubes from waste cooking palm oil as adsorbent materials for the adsorption of heavy metal ions

Environmental Science and Pollution Research - In this work, waste cooking palm oil (WCPO)-based carbon nanotubes (CNTs) with encapsulated iron (Fe) nanoparticles have been successfully produced...     

Industrial hygiene and toxicity studies in unorganized bone-based industrial units

A large variety of ornamental and decorative items are manufactured from bone waste by various unorganized sectors in India. An initial survey indicated that workers were exposed at various phases of final product. The subjects (12 industrial units) were tested for total suspended particulate matter (TSPM), particulate matter <10  $\upmu $ m (PM₁₀), and particulate matter <2.5  $\upmu $ m (PM_2.5). Prevalent levels of TSPM ranged between 2.90 and 5.89 mg m^???3. Respirable fractions of occupational dust as PM₁₀ and PM_2.5 were found in the range of 0.30?C2.08 and 0.26?C0.50 mg m^???3, respectively. Cytotoxicity study was conducted using hemolysis as a sensitive marker. In an in vitro study, rat RBCs were exposed to the concentration of 25?C1,000  $\upmu $ g/ml for 15?C120 min. A considerable variation was observed in the hemolytic activity of samples collected from different areas. At 500  $\upmu $ g/ml concentration, the hemolytic activity (12 h) was found to be in the range of 18?C25%. Due to limitation in sample mass of respirable fractions, only one concentration (100  $\upmu $ g/ml/2 h) was used for comparative study on hemolysis of RBCs caused by PM₁₀ and PM_2.5. Interestingly, the hemolytic activity was more at PM_2.5 than PM₁₀ and TSPM. These results suggest that the respirable particles are capable of reaching deep into the respiratory system. The finding is significant notably when there are no standards available in occupationally exposed populations. This is the first such study. Data could be of importance to policy makers and regulators.     

Evaluation of the potential of Sasobit® to reduce required heat energy and CO2 emission in the asphalt industry

Warm-mix asphalt (WMA) has been gaining popularity in the asphalt industry primarily because of its ability to lower the energy required to blend asphalt mixes, which in turn results in less fuel consumption, slower aging of the asphalt binder and reduced emission of greenhouse gases. This paper evaluates the effects of different quantities of a WMA additive known as Sasobit^® on the required heat energy and the amount of CO₂ produced to increase the temperature of two aggregates from three sources and one binder from 25 °C to the point of mixing. The results showed that incorporating 1% Sasobit^® can potentially reduce the required heat energy and amount of CO₂ produced by 2.8% and 3.0%, respectively, for all aggregate types and sources investigated. The paper also presented design charts that enable energy policy makers and engineers to select the appropriate Sasobit^® content to produce the most cost effective asphalt mixture with less environmental impact. The design charts show that 1.6% Sasobit^® content is the most suitable proportion to be blended into the asphalt binder without compromising pavement resistance against fatigue failure. Two similar aggregates from different sources may exhibit similar specific gravities, but their specific heat capacities can vary widely. These differences have a significant effect on the required heat energy, asphalt production cost and the amount of emissions released into the environment.     

Distribution and baseline values of trace elements in the sediment of Var River catchment,southeast France

This study reports on the determination of trace element (TE)—Li, As, Co, Cs, Cu, Pb, U, and Zn—and major element (ME)—Si, Al, Fe, Mg, Ca, Mn, Na, and K—concentrations in 18 riverbed sediments and a sediment core from the Var River catchment using inductively coupled plasma mass spectrometry (ICP-MS). The results were compared with those of a reference sediment core, and the contribution of clay and organic carbon contents in the distribution of TE and ME in the sediment samples was investigated. The mean concentrations of the ME were comparable in both core and riverbed samples and were within the natural averages. In the case of TE, the concentrations were lower in riverbed sediment samples than those found in the sediment core. High mean concentration of As was observed (7.6 μg g^?1) in both core and riverbed sediments, relatively higher than the worldwide reported values. The obtained data indicated that the natural high level of arsenic might be originated from the parent rocks, especially metamorphic rocks surrounding granites and from Permian sediments. Statistical approach, viz., Pearson correlation matrix, was applied to better understand the correlation among TE in both riverbed and sediment core samples. No significant metallic contamination was detected in the low Var valley despite of the localization of several industrial facilities. Therefore, results confirm that the concentrations of the TE obtained in the riverbed sediments could be considered as a baseline guide for future pollution monitoring program.     

Evaluation of food industry by-products as feed in semi-arid dairy farming systems: the case of Jordan

Dairy feeding systems in many semi-arid countries are based on imported concentrates and forages. This has economic and ecological implications given the increase in global feed prices and greenhouse gas (GHG) emissions from land use change. This paper aims to explore alternative dairy feeding systems under semi-arid conditions, using Jordan as an example. The feedings systems under investigation vary in their share of food industry by-products (replacing concentrates in the diet) and are compared against the current concentrate-based feeding systems. The systems are evaluated against three criteria: their nutritional value, their impact on the cost of milk production, and their GHG mitigation potential. Feed samples from eleven food industry by-products and ten conventional feeds were collected from food factories and from three typical dairy farms, representing the typical large-, medium- and small-scale farm types, respectively. Feed samples were analysed for their chemical composition and metabolisable energy contents. In addition, economic and production farm data were collected and entered into a model for GHGs calculation and economic evaluation. The results suggest that inclusion of locally available food industry by-products in the rations of milk cows in semi-arid production systems can be instrumental in reducing production costs and mitigating GHG emissions. Cost of milk production in the model farms can be lowered by up to 14 %; mitigation of CO₂ eq. emission ranged between 70 and 290 g CO₂ eq./kg milk. The degree to which these benefits can be reaped is positively related to the level of inclusion of by-product feeds in lactating cows’ diets.     

Microplastics in freshwater ecosystems: a recent review of occurrence,analysis, potential impacts,and research needs

Environmental Science and Pollution Research - The utilization of plastics has now become a threat to the environment as it generates microplastic particles (&lt;5 mm in size). The increasing...     

Key indicator tools for shallow slope failure assessment using soil chemical property signatures and soil colour variables

Slope failure has become a major concern in Malaysia due to the rapid development and urbanisation in the country. It poses severe threats to any highway construction industry, residential areas, natural resources and tourism activities. The extent of damages that resulted from this catastrophe can be lessened if a long-term early warning system to predict landslide prone areas is implemented. Thus, this study aims to characterise the relationship between Oxisols properties and soil colour variables to be manipulated as key indicators to forecast shallow slope failure. The concentration of each soil property in slope soil was evaluated from two different localities that consist of 120 soil samples from stable and unstable slopes located along the North-South Highway (PLUS) and East-West Highway (LPT). Analysis of variance established highly significant difference (P < 0.0001) between the locations, the total organic carbon (TOC), soil pH, cation exchange capacity (CEC), soil texture, soil chromaticity and all combinations of interactions. The overall CIELAB analysis leads to the conclusion that the CIELAB variables lightness L*, c* (Chroma) and h* (Hue) provide the most information about soil colour and other related soil properties. With regard to the relationship between colour variables and soil properties, the analysis detected that soil texture, organic carbon, iron oxide and aluminium concentration were the key factors that strongly correlate with soil colour variables at the studied area. Indicators that could be used to predict shallow slope failure were high value of L*(62), low values of c* (20) and h* (66), low concentration of iron (53 mg kg^?1) and aluminium oxide (37 mg kg^?1), low soil TOC (0.5%), low CEC (3.6 cmol/kg), slightly acidic soil pH (4.9), high amount of sand fraction (68%) and low amount of clay fraction (20%).