Waste Fe(III)/Cr(III) hydroxide as adsorbent for the removal of Cr(VI) from aqueous solution and chromium plating industry wastewater

Fe(III)/Cr(III) hydroxide, a waste material from the fertilizer industry, has been used for the adsorption of Cr(VI) from aqueous solution, over a range of initial metal ion concentrations (5-30 mg litre(-1)), agitation times (1-180 min), adsorbent dosages (100-1200 mg per 50 ml), temperatures (24, 29 and 38 degrees C) and pH values (4.5-10). The adsorption of Cr(VI) increased with the initial concentration of Cr(VI) and with temperature. The process of uptake follows both the Langmuir and the Freundlich isotherm models. The applicability of Lagergren and empirical kinetic models has also been investigated. Almost quantitative removal of Cr(VI) at 10 mg litre(-1) in a 50-ml solution by 500 mg of adsorbent was found at an equilibrium pH of 5.6. The efficiency of chromium removal was also tested using wastewater from the chromium plating industry.     

The sustainable development oxymoron: quantifying and modelling the incompatibility of sustainable development goals

ABSTRACT

In 2015, the UN adopted a new set of Sustainable Development Goals (SDGs) to eradicate poverty, establish socioeconomic inclusion and protect the environment. Critical voices such as the International Council for Science (ICSU), however, have expressed concerns about the potential incompatibility of the SDGs, specifically the incompatibility of socio-economic development and environmental sustainability. In this paper, we test, quantify and model the alleged inconsistency of SDGs. Our analyses show which SDGs are consistent and which are conflicting. We measure the extent of inconsistency and conclude that the SDG agenda will fail as a whole if we continue with business as usual. We further explore the nature of the inconsistencies using dynamical systems models, which reveal that the focus on economic growth and consumption as a means for development underlies the inconsistency. Our models also show that there are factors which can contribute to development (health programmes, government investment) on the one hand and ecological sustainability (renewable energy) on the other, without triggering the conflict between incompatible SDGs.     

Case study of testing heavy‐particle concentrator‐aided remediation of lead‐contaminated rifle shooting range soil

Trials were conducted to optimize the parameters of a heavy‐particle concentrator (HPC) for the remediation of soil stockpiles contaminated by metallic lead at the Mount Stuart training area in Townsville, Queensland, Australia. A range of treatment methods, including orbital screen, HPC, and a combination of orbital screen and HPC were evaluated. The treatment efficiency, as well as reductions in Pb and Australian Standard Teaching Procedure values, was ranked: Orbital screen + HPC < HPC < 2nd run through HPC. The combination of orbital screening, HPC, and phosphate‐aided immobilization completely remediated the stockpiled material by reducing total lead to below the Australian National Environmental Protection Measure Health Investigation Level for Soil Contaminant (Recreational; < 600 milligrams lead per kilogram). The optimized parameters of HPC at 4 tonnes per hour of the < 40 millimeter (mm) orbital screen feed fraction were: inclination angle 4°, trommel speed 1,860 revolutions per minute (rpm), HPC belt speed 3.5 rpm, material distribution chute extension 100 mm and water flow 480 liters per minute.     

Effect of hypoxia on the circulating levels of essential mineral elements in rats

Changes occurring in concentrations of certain trace metals and electrolytes viz. chromium, copper, zinc, sodium, potassium, calcium, magenesium and chloride in plasma of rats exposed to intermittent hypobaric hypoxia were evaluated. Batches of Sprague-Dowley rats (12 in each group) were exposed for 1, 7,14 and 21 days to a simulated altitude 7,620 m for 6 h per day and one group of unexposed animals was kept as control. There was a significant rise of 153% in plasma chromium levels of 1 day exposed group in comparison to the unexposed group which tends to normalise on subsequent exposure. There was a gradual increase in plasma copper levels of 9.0, 28.2, 62.6 and 65.6% respectively in 1,7,14 and 21 days exposed rats in comparison to unexposed rats. On the other hand plasma zinc levels were seen to be decreasing during entire exposure. Plasma sodium levels decreased initially in 1 and 7 day exposed rats and increased in later groups whereas plasma potassium levels of exposed groups remained low in comparison to unexposed group. Chloride levels were found to be elevated in 14 and 21 day exposed groups. The plasma calcium and magnesium levels were higher in all exposed groups over unexposed groups. Changes in chromium, copper and zinc observed in the present study during exposure to hypoxic stress may be responsible for the hyperglycemia and anorexia encountered during intial phase of high altitude acclimatisation.     

Assessment of water pollution in different bleaching based paper manufacturing and textile dyeing industries in India

Paper industries using different raw materials such as hard wood, bamboo, baggase, rice-straw and waste papers and bleaching chemicals like chlorine, hypochlorite, chlorine dioxide, hydrogen peroxide, sulphite and oxygen were studied to estimate organic pollution load and Adsorbable Organic Halides (AOX) per ton of production. The hard wood based paper industries generate higher Chemical Oxygen Demand (COD) loads (105–182 kg t⁻¹) and Biochemical Oxygen Demand (BOD) loads (32.0–72 kg t⁻¹) compared to the agro and waste paper based industrial effluents. The bleaching sequences such as C–EP–H–H, C–E–H–H, C–E–Do–D1 and O–Do–EOP–D1 are adopted in the paper industries and the molecular elemental chlorine free bleaching sequence discharges low AOX in the effluent. The range of AOX concentration in the final effluent from the paper industries was 0.08–0.99 kg t⁻¹ of production. Water consumption was in the range of 100–130 m³ t⁻¹ of paper production for wood based industries and 30–50 m³ for the waste paper based industries. Paper machine effluents are partially recycled after treatment and pulp mill black liquor are subject to chemical recovery after evaporation to reduce the water consumption and the total pollution loads. Hypochlorite bleaching units of textile bleaching processes generate more AOX (17.2–18.3 mg l⁻¹) and are consuming more water (45–80 l kg⁻¹) whereas alkali peroxide bleaching hardly generates the AOX in the effluents and water consumption was also comparatively less (40 l kg⁻¹ of yarn/cloth).     

Satellite detection of bird communities in tropical countryside.

The future of biodiversity hinges partly on realizing the potentially high conservation value of human-dominated countryside. The characteristics of the countryside that promote biodiversity preservation remain poorly understood, however, particularly at the fine scales at which individual farmers tend to make land use decisions. To address this problem, we explored the use of a rapid remote sensing method for estimating bird community composition in tropical countryside, using a two-step process. First, we asked how fine-grained variation in land cover affected community composition. Second, we determined whether the observed changes in community composition correlated with three easily accessible remote sensing metrics (wetness, greenness, and brightness), derived from performing a tasseled-cap transformation on a Landsat Enhanced Thematic Mapper Plus image. As a comparison, we also examined whether the most commonly used remote sensing indicator in ecology, the Normalized Difference Vegetation Index (NDVI), correlated with community composition. We worked within an agricultural landscape in southern Costa Rica, where the land comprised a complex and highly heterogeneous mosaic of remnant native vegetation, pasture, coffee cultivation, and other crops. In this region, we selected 12 study sites (each < 60 ha) that encompassed the range of available land cover possibilities in the countryside. Within each site, we surveyed bird communities within all major land cover types, and we conducted detailed field mapping of land cover. We found that the number of forest-affiliated species increased with forest cover and decreased with residential area across sites. Conversely, the number of agriculture-affiliated species using forest increased with land area devoted to agricultural and residential uses. Interestingly, we found that the wetness and brightness metrics predicted the number of forest- and agriculture-affiliated species within a site as well as did detailed field-generated maps of land cover. In contrast, NDVI and the closely correlated greenness metric did not correlate with land cover or with bird communities. Our study shows the strong potential of the tasseled-cap transformation as a tool for assessing the conservation value of countryside for biodiversity.     

Diversity of microflora in the gut and casts of tropical composting earthworms reared on different substrates

The diversity of fungi, bacteria, yeast, actinomycetes and protozoa were analysed in the gut and casts of Eudrilus eugeniae, Lampito mauritii, Eisenia fetida and Perionyx excavatus, both qualitatively and quantitatively as influenced by different feed substrates like clay loam soil, cowdung and pressmud. While actinomycetes (Streptomyces albus, S. somaliensis, Nocardia asteroides, N. caviae and Saccharomonosporia) were not digested by any of these species of worms, protozoa (Amoeba proteus, A. terricola, Paramecium trichium, Euglena viridis, E. orientalis, Vorticella picta and Trichomonas hominis) and yeast (Candida tropicalis, C. krusei C. albicans and Cryptococcus neoformans) were totally digested. Certain species of fungi (Saksenae vasiformis, Mucor plumbeus, Cladosporium carrionii, C. herbacium, Alternaria sp., Cunninghamella echinulata, Mycetia sterila, Syncephalostrum racemosum, Curvalaria lunata, C. geniculata and Geotrichum candidum) and bacteria (Pseudomonas aeruginosa, Bacterium antitratum, Mima polymorpha, Enterobacter aerogenes, E. cloacae, Proteus vulgaris, P. mirabilis, P. rettgeri, Escherichia coli, Staphylococus citreus, Bacillus subtilis, B. cereus, Enterococci and Micrococci) were completely digested. Certain other species were not digested fungi like Aspergillus fumigatus, A. flavus, A. ochraceous, Trichoderma koningii (except by Eeugeniae), Fusarium moniliforme (except by E. eugeniae) and Rhizopus sp., and bacteria like Klebsiella pneumoniae and Morganella morganii) and these were multiplied during the transit of the organic residues through the gut of worms. The microbial proliferation was more in the casts, due to the environment prevailing--rich in nutrient supply and large surface area available for growth and reproduction of the microbes that lead to enhanced microbial activity and humic acid contents in the casts.     

A comparative assessment of growth,pigment and enhanced lipid production by two toxic freshwater cyanobacteria Anabaena circinalis FSS 124 and Cylindrospermopsis raciborskii FSS 127 under various combinations of nitrogen and phosphorous inputs

Environmental Science and Pollution Research - Nitrogen and phosphorous are important nutritional regulators for the growth of cyanobacteria, thereby having a significant impact in bloom formation...     

Recycling of ‘waste’ FE(III)/CR(III) hydroxide for the removal of nickel from wastewater: Adsorption and equilibrium studies

Effects of Ni(II) concentration, agitation time, temperature and pH on adsorption of Ni(II) on Fe(III)/Cr(III) hydroxide, a waste by-product from fertilizer industry, have been investigated. The percent adsorption increased from 55 to 69% with increase in temperature from 20 to 40°C and from 32 to 77% with increase in pH from 3.7 to 7.5 and from 38 to 79% with decrease in Ni(II) concentration from 100 to 25 mg/L. The equilibrium data fit well with the Langmuir isotherm and the adsorption capacity was found to be 21.0 mg/g at 30°C. Thermodynamic parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were evaluated. The adsorption rate constant was higher at lower concentration of Ni(II) and at higher temperature. Desorption studies show that 70% of Ni(II) can be desorbed from the adsorbent at pH 4.0. The adsorbent was tested using nickel plating industry wastewater and the maximum percent removal was 97.