High Cation Exchange Capacity Research Articles

Impact of the Salt Concentration and Biophysical Cohesion on the Settling Behavior of Bentonites

The flocculation behavior of clay minerals in aquatic environments is an important process in estuarine and riverine dynamics, where strong gradients in salinity can locally occur. Various contradicting observations have been reported in the literature on the impact of salt concentration on the settling process of cohesive sediments. To address this issue in a systematic manner, we investigate the settling behavior of clay minerals as a function of the salt concentration of the ambient water. Specifically, we focus on montmorillonite as a prototype clay mineral with a high cation exchange capacity (CEC). To this end, we study suspensions of Wyoming bentonite (Volclay SPV) as a very important constituent for many constructional and industrial purposes. We perform an experimental campaign to study the settling behavior of moderately turbid montmorillonite concentrations in monovalent salt solutions with different salinities (sodium chloride) to represent different environments ranging from deionized to ocean water, respectively. The subsequent settling process was monitored by taking pictures by a camera in regular time intervals over a total observation time up to 48 h. In addition, a modified hydrometer analysis is conducted to determine the grain size distribution (in terms of an equivalent diameter) of the flocculated clay suspension in salt water. Despite the rather high cation exchange capacity of the investigated clay (CEC=88.1), our results show that the settling speed drastically increases within a range of 0.6–1.0 PSU and stays approximately constant for higher salinities. This critical salt concentration is defined here as the critical coagulation concentration (CCC) and lies well below the salinity of natural open water bodies. The hydrometer analysis revealed that 60% of the agglomerates exceed the equivalent grain size of 20 μm. Finally, the findings of this study are supplemented with experiments studying the effect of Extracellular Polymeric Substances (EPS) on the flocculation behavior of bentonite in salt water. Our results demonstrate that salinity is the original trigger for flocculation, whereas EPS allows for even larger floc size but it does not play a significant role for the settling processes of bentonite in estuarine environments.

Long‐term conservation agriculture helps in the reclamation of sodic soils in major agri‐food systems

AbstractGlobally crop production is impaired by soil salinity and sodicity and to maintain the sustainability of the production systems under such degraded lands, conservation agriculture (CA) may be an alternative in arid and semiarid regions. An experiment was initiated with different agri‐food systems with CA‐based practices to understand the reclamation potential of sodic soil after continuous cultivation for 4 and 9 years. This included: (i) conventional tillage (CT)‐based rice‐wheat system (Sc1); (ii) partial CA with puddled rice‐zero tillage (ZT) wheat and mungbean (Sc2); (iii) ZT rice‐wheat‐mungbean (Sc3); (iv) ZT maize‐wheat‐mungbean (Sc4). Soil samples were collected from 0 to 15 and 15 to 30‐cm depth after 4 and 9 years of wheat harvesting. Results showed an 18% decline in pH2 with Sc2 and ~30% decline in EC2 with Sc2 and Sc3 at upper soil depth after 9 years. Higher cation exchange capacity by 35% and 89% in Sc2 and 38% and 58% in Sc3 after 4 and 9 years was found, respectively, over initial levels. A decrease in exchangeable sodium percentage was recorded in Sc2 by 43% and 50%, after 4 and 9 years over the initial level, respectively. The oxidizable carbon and total organic carbon were increased by ~76%, 69%, and 64% in Sc4, Sc3, and Sc2, respectively, over initial values at 0–15 cm soil depth. Results showed that the CA‐based rice‐wheat‐mungbean system had more reclamation potential than other studied systems. Therefore, long‐term CA practices involving ZT with crop residue recycling and efficient crop rotations have the potential to reduce the sodicity stress and improve soil organic carbon thereby bringing the sodic lands under productive crop cultivation.

Application of an experimental design in the hydrothermal synthesis of GIS-NaP zeolite from brickwall wastes

This article reports the results of an investigation carried out in order to obtain zeolitic material of the GIS-NaP type with high cation exchange capacity using brick waste. The hydrothermal synthesis was carried out in a stainless-steel reactor using NaOH activating solutions at concentrations of 2.0, 2.5 and 3.0 M, activation temperatures of 100, 120 and 140 ℃ and activation times of 7, 8 and 9 hours. The product obtained was characterized by X-ray Fluorescence, Scanning Electron Microscopy (SEM), X-ray Diffraction, and Cation Exchange Capacity (CEC).The results obtained showed that for the hydrothermal conversion test at 140 ℃/2 M/7 hours, GIS-NaP synthetic zeolite with a cation exchange capacity equal to 163.5 meq/100 g was obtained. The statistical analysis, applying a factorial experimental design, indicated that the main factors with a great effect on the cation exchange capacity (CEC) are the activation temperature and the interaction between it and the concentration of the activating solution, with a degree of significance of 0.049250 and 0.056631 for a confidence level of 90.82%. An empirical mathematical model was developed and validated by applying ANOVA analysis that considers the interaction effects of all factors and was optimized by applying the response surface methodology.

Cadmium Enrichment and Bioavailability of Quaternary Profiles in Nansha District, Guangzhou, China

Comprehending the distribution pattern and enrichment rule of the heavy metal cadmium (Cd) in soil and grasping its activity and influencing factors is crucial for guaranteeing the soil environment safety of agricultural and construction land and improving the overall quality of the soil environment. The concentration of heavy metal Cd in the quaternary profile of Nansha was measured, and the pollution level was evaluated using the geographical accumulation index (Igeo) and potential ecological risk index (Er). Then, we determined the correlation between the total amount of Cd and the physicochemical properties of the soil using factor analysis (FA-MLR). The results showed that the average content of Cd in shallow soil (0-20 cm) in the Nansha area was 0.54 mg·kg-1, and the soil was mainly weakly acidic and neutral. The average content of Cd in deep soil (150-200 cm) was 0.42 mg·kg-1, and the soil was mainly neutral. At the same time, the variation coefficient of Cd content in shallow soil was significantly greater than that in deep soil, and Cd content tended to be consistent with the increase in depth. The Cd content of quaternary sediments showed a bimodal distribution with depth, reaching a peak at 20-25 m and 5-10 m, respectively, whereas the core sediments in this section were mostly marine sediments of silt and silty clay, with high cation exchange capacity and organic matter. The Igeo and Er of Cd in the fine-grained sediments dominated by clayey soil were significantly higher than those in the coarse-grained sediments dominated by sandy soil. The difference in soil pH value led to the different trend of Cd content with depth; the migration amount and vertical migration depth of Cd in deep soil were greater in the acidic environment. The influence of pH change on the migration and transformation of Cd was not completely reflected in the influence on the total amount of Cd, but more importantly, it changed the effective state of Cd, thus affecting the bioavailability of Cd. The unstable Cd composed of water-soluble, ion-exchangeable, and carbonate states accounted for 37.92%-49.10% of the total Cd, resulting in a strong instability of soil Cd. Further investigation on the migration and toxicity of heavy metals associated with human health risks is needed in future studies.

KAJIAN PEMANFAATAN LIMBAH DAUN KAYU PUTIH UNTUK MEMPERBAIKI FAKTOR PEMBATAS KESUBURAN TANAH

The utilization of eucalyptus leaf waste in the processing unit of the eucalyptus oil factory has not been carried out optimally and has great potential as raw material for making organic fertilizer in the form of compost. This study aimed to study the potential use of eucalyptus leaf compost to improve soil fertility limiting factors in Jati Plus plantations. This research was conducted at the Department of Research and Innovation of the Perhutani Forestry Institute, Cepu, Central Java, and in the chemical laboratory of the Department of Soil, FPUB. This study used a completely randomized design consisting of four treatments and three replications. The results showed that eucalyptus leaf waste could be composted with organic carbon content, total nitrogen, total P2O5, total K2O, high organic matter content, high cation exchange capacity, and neutral pH. Perhutani's Teak Plus Plantation has fertility limiting factors on the ustic soil moisture regime, alkaline soil reaction, and clay texture. Eucalyptus leaf waste compost can be used as organic material for the strategic direction of soil management in several Jati Plus Perhutani plantation areas.

Characteristics of vineyard soils derived from Plio‐Quaternary landforms (raña or rañizo) in southern Europe

AbstractSoil is an essential component in viticulture. The study reported here concerns the assessment of the morphology chemical and physicochemical features of typical, well‐developed and representative evolved Mediterranean soils near Anchuras (Spain, southern Europe), a site with soils that developed on old landforms (Plio‐Quaternary) called ‘raña’ and/or ‘rañizo’. The soils under study were described and sampled by conducting soil surveys. Selected soil properties, such as texture, bulk density, pH, electrical conductivity (EC), cation exchange capacity (CEC) and contents of organic matter, nutrients, etc., were analysed using standard procedures. The results showed that these landscape surfaces were, linked with specific soil properties such as low pH (from 4.4 to 5.3) and EC (from 0.15 to 0.02 dSm−1), clay contents (20.1%–48.8%), high CEC (26–39 cmol/kg), and low base saturation values (from 11.2% to 17.2%), and have an adequate and singular pedological potential in relation to the ‘terroir’ or ‘terron’ concepts that meet suitability criteria. Furthermore, the information provided by this study, fundamentally through the weathering indices, supports the role of soil‐forming factors and their influence on soil properties. In addition, as these landforms and underlying materials have abundant and extensive rock fragments, the role of these soils in the context of vineyard growth and development has been investigated.Highlights There are unknown conceptual zones that support production of wine This study highlights the importance and uniqueness of vineyard soils linked to old plioquaternary surfaces. Pedogeomorphologic vineyard constraints can serve as a basis for implementing a PDO The association soils‐old surfaces can contribute to the identity and reputation of a viticultural zone

Influence of environmental-friendly bio-organic ameliorants on abiotic stress to sustainable agriculture in arid regions: A long term greenhouse study in northwestern Egypt

The problem of soil salinity is rapidly increasing, with more than 950 million hectares affected by salinity stress (Arora et al., 2017). The amelioration of saline-sodic soils using chemical ameliorates could increase CO2 emissions and soil degradation. Therefore, amending saline-sodic soil with environmentally friendly bio-organic ameliorants such as brewer's spent grain (SG) and Azospirillum (A. brasilense) bacteria could represent a safe and cheaper approach compared to other organic (compost; CT) and mineral fertilizers. Under greenhouse conditions, maize was grown in saline-sodic soil amended with bio-organic ameliorants. Nine treatments were included; (i) SG1 (23.8 t ha−1); (ii) SG2 (47.6 t ha−1); (iii) TC1 (23.8 t ha−1); (iv) TC2 (47.6 t ha−1); (v) injection of A. brasilense with corn seeds (Az); (vi) combination of A. brasilense and SG (Az + SG1); (vii) combination of A. brasilense and compost (Az + TC1); (viii) mineral fertilizers (NPK) and (ix) the control (CK). The results revealed that soil amended with Az and SG2 significantly decreased the exchangeable sodium percentage (ESP) and higher cation exchange capacity (CEC). Compared with the control, the exchangeable sodium (Ex-Na+) concentration was decreased by 53.2 and 49.27%, for Az and Az + SG1 treatments, respectively. The fresh- and dry weight observed for Az + SG1, SG2, and Az treatments were increased compared to TC1, TC2, NPK, and CK treatments. The grain and biological yields were higher in Az + SG1 and SG2 than in TC2, NPK ameliorants, and CK. The bio-organic ameliorants alleviated the abiotic stress, enhance the growth and productivity of corn plants, decrease soil ESP and Na+ content, and enhance soil fertility. In conclusion, the application of SG2 can enhance the growth, and productivity of maize grown under salinity-sodicity stress. Therefore, SG2 and Az + SG1 are recommended for direct application in saline-sodic soil.

Critical values of soil solution Al3+ activity and pH for canola and maize cultivation in two acidic soils.

Aluminum (Al) toxicity caused by soil acidification is the main constraint for crop growth in tropical and subtropical areas of southern China. The critical values of soil solution Al3+ activity and pH for crops in acidic soils can provide a useful reference for soil acidity amelioration. A pot experiment in a greenhouse was conducted to investigate the critical values of soil solution Al3+ activity and pH for canola and maize in an Ultisol and an Alfisol. The critical values of soil solution Al3+ activity in Ultisol and Alfisol for canola were 1.5 and 10.0 μmol L-1 , and 13.9 and 30.4 μmol L-1 for maize, respectively. The Al tolerance varied with soil type for the same variety of crop. There was more biomass of roots and shoots and higher plant height under the same Al3+ activity, and thus greater critical values of soil solution Al3+ activity for both crops in Alfisol than those in Ultisol, owing to higher Ca2+ /Al3+ , Mg2+ /Al3+ and K+ /Al3+ ratios in soil solution caused by higher cation exchange capacity and exchangeable base cations in Alfisol, when compared with those in Ultisol. The critical values of soil solution pH for canola and maize in Ultisol were 5.09 and 4.72, respectively; while those in Alfisol were 4.87 and 4.54, respectively. The critical values of Al3+ activity were higher for maize than for canola and the critical values for both crops were higher in Alfisol than in Ultisol. The critical soil pH for both crops showed opposite trends to soil Al3+ activity. © 2022 Society of Chemical Industry.

ANALISIS KARAKTERISTIK SIFAT KIMIA TANAH GAMBUT SETELAH DIINKUBASI DENGAN KASCING DARI CAMPURAN KOTORAN AYAM, BONGGOL PISANG DAN AMPAS TAHU

Peat soil has a high cation exchange capacity, low base saturation, has a low content of K, Ca, Mg, P and also has a low content of micro elements (such as Cu, Zn, Mn and B). This study aims to determine the chemical properties of peat soil that has been incubated with vermicompost fertilizer from a mixture of banana weevil, chicken manure and tofu dregs. The test was carried out by mixing peat soil and vermicompost according to the treatment in 2 kg polybags. After thoroughly stirring, the mixture was sprinkled with peat water once a day until it reached field capacity. The mixture was then incubated for 2 weeks. Each treatment was repeated 3 times. This study was conducted with a non-factorial randomized design as follows: PO = Control (1 kg of peat soil), P1 = 1 kg of peat + 500 grams of vermicompost, P2 = 1 kg of peat soil + 1 kg of vermicompost and Based on the results of the research analysis can be taken the conclusion that peat soil incubated for two weeks increased the chemical properties of the soil, namely: improving pH by P1 0.15 units and P2 by 0.175 units, total N by 0.43% and P2 by 0.755 %, P by P1 733.52 and P2 was 922,015, K was 2,145 and P2 was 2,575, Ca was 1,675 and P2 was 2,825, Mg was P1 3 and P2 was 4,27 and increased Na by 0,09 and P2 by 0,045.

Assessment of pyrene adsorption on biochars prepared from green infrastructure plants: Toward a closed-loop recycling in managing toxic stormwater pollutants

Recently biochar is receiving increased attention as an alternative filter medium for enhanced stormwater management. This study attempted to recycle plants harvested from the upper green infrastructure (GI) component for reuse in the lower GI component as a filter medium. Dawn redwood (DR) and bridal wreath (BW) were harvested and converted to biochar. Leaves and branches of each plant species were pyrolyzed at 300 and 500 °C and the prepared biochars were characterized and evaluated for their adsorption capacity of pyrene, one of the major polycyclic aromatic hydrocarbons (PAHs) in urban stormwater runoff. The biochar made from DR leaf at 300 °C showed the highest pyrene adsorption efficiency and was well-fitted with pseudo-second order kinetics and Freundlich isotherm. The first biochar regeneration cycle demonstrated that both thermal and solvent extraction showed high pyrene adsorption efficiency recovery with values of 98.8 and 98.0%, respectively. The relationships between surface properties and adsorption capacities of biochar for PAHs and heavy metals, the two major toxic stormwater pollutants, were further investigated using data pooled from the existing studies. The literature data analysis showed that biochars produced at a lower pyrolysis temperature (~300 °C) can efficiently remove PAHs and heavy metals due to higher hydrophobic interactions and higher cationic exchange capacity, respectively. This study suggests the potential feasibility of closed-loop recycling of GI plants for sustainable stormwater treatment and carbon sequestration.

EFFECT OF BIOGAS SLURRY ON COMPOSTING PROCESS AND QUALITY OF CATTLE MANURE-BASED COMPOST AND VERMICOMPOST

Regarding the increasing demand of good organic manure, we made an attempt to generate a modified vermicompost from biogas slurry amended cattle manure. For this, six trials including control were run in pots by adding 2−10% (w/w, fw.) biogas slurry to cattle manure for 21 days for composting and 60 days for vermicomposting using E. eugeniae earthworms (10 per 500 g) under aerobic condition keeping moisture level of 70±5% within the overall temperature range of 13−39°C. The use of bacterial inoculants increased the agricultural quality of the compost and accelerated the composting process. After being maturity, pH of the vermicompost reached to 7.66, indicating that it has excellent nutrient releasing capability. Since EC of the produced vermicompost is less than 1.60 dS m−1, it has high cation-exchange capacity, which is beneficial to soil texture and plant health. An increment in 163% of available P in the vermicompost (6.35 ± 0.78 mg g-1, dw) than that in the compost and the highest increment of 264% with respect to control indicated that it was a better organic fertilizer and hence might be an alternative to P2O5. The worm-processed material for trials T1-T5 showed 10.0–32.5% more exchangeable K than control (T0). An increment of 43.84% in total N and an decrease of 15.6% in total organic C makes the vermicompost ideal for use for its lowest C:N ratio of 15:1, whereas it was 35:1 in compost. Each of the N-P-K contents was elevated significantly that made it a potential organic fertilizer. Comparison of the key parameters with vermicomposts of buffalo, pig, goat, horse, chicken and sheep manures of different countries confirms that the produced vermicompost could serve as an excellent organic manure.

Development of novel montmorillonite-based sustained release system for oral bromopride delivery.

The drug delivery systems are an important strategy of pharmaceutical technology to modulate undesirable properties, increasing efficacy, and reducing the side effects of active pharmaceutical ingredients (API). The sustained release is a type of controlled-release system that provides a suitable drug level in the blood through a slow release rate. An interesting alternative to achieve a controlled release is the application of carrier materials such as polymers, cyclodextrins, and clays. Sodium montmorillonite (Na-MMT) is a biocompatible natural clay that allows the insertion of organic compounds in interlamellar space, owing to its high cation exchange capacity and large internal surface area. Bromopride (BPD) is an aminated compound with antiemetic properties classified as class II (low solubility, high permeability) of the Biopharmaceutical Classification System (BCS). Herein, the aim of the study was the development and investigation of a drug delivery system formed by intercalation of BPD with Na-MMT. The results indicate the successful intercalation of this API with the lamellar silicate, meanwhile, there was no evidence of BPD intercalation in organic montmorillonite. The Na-MMT/BPD molecular complex exhibits a sustained release in performed assays. Molecular dynamics simulations suggested that BPD molecules interact with the montmorillonite layer through ion-dipole interactions and also between BPD molecules, forming hydrogen bonds web into montmorillonite interlayer space. The new drug delivery system showed an alternative to achieve the BPD sustained release, which may improve its pharmacological performance in therapeutic applications.

Effects of Brewery Beer Bio-sludge and Liquid Biofertilizer on Performance of the Malt Barley Yield, Grain Quality and Soil Fertility at Arsi and West Arsi Zone, 2017 Ethiopia

This study was conducted to investigate the effects of beer bio-sludge, liquid bio-fertilizer and inorganic fertilizer application to barley (Hordeum vulgare L.) var. traveler on the plant performance, grain quality and some soil properties. Treatments applied were: (1) Beer Bio-Sludge (BBS) (2) Liquid Bio-Fertilizer (LBF) (3) Chemical Fertilizer (CHF) (4) No Fertilizer (Control). The experiment was laid-out in simple plot design and randomized over locations. The plot sizes were 10m x 10m = 100m2. Phonologic, diseases, agronomic and yield, data were collected. Grain quality, sludge, liquid fertilizer and soil analysis were done. Sample sizes of ten plants/plot were used for agronomic data i.e., for plant height, panicle length, number of tiller and spikelet/panicle. Yield and yield related data; Thousand Kernel Weight (TKW), Straw Weight (STW) and Yield (YLD) were collected from 1m x 1m = 1m2 plot size. Significantly (p<0.05%) higher thousand kernel weight (51.63g), straw weight (1145 kg ha1) and grain yield (70.34 qt ha1) were obtained from soil applied with BBS and followed by LBF (50.25g, 1035kg ha1 and 65.08 qt ha1). Beer bio-sludge increased the yield of barley by (2.2, 4.12 and 9.17%) over that of LBF, CHF and Control, respectively. The linear correlation analysis indicated that, seed yield of malt barley had a positive and significant correlation with most of growth parameters and yield. The soil analysis result revealed that, soil in the two locations were in silt-clay textural classification and moderately acidic ranging from 5.53 to 5.53. Similarly, BBS improved soil chemical (acidity) and physical properties (textural classes) as compared to inorganic and non-fertilizer. The BBS treated soil showed higher value for some of major and secondary soil elements namely; available phosphors (17.11mg/kg (ppm)), potassium (553.22mg/kg (ppm)) calcium (2,499.01mg/kg (ppm)), magnesium (277.33 mm/kg(ppm), Sulfur (16.93mg/kg(ppm), high total nitrogen (0.32%), organic carbon (4.42%) and Cation Exchange Capacity (CEC) (32.01Meq/100g soil) as compared to others treatments. There was no effects of BBS treated soil on heavy metals concentration such as, Cu, Mo, Ni, Zn, Pb, Cd and Hg is comparably in accepted international standard ranges. H/ever, Nitrogen Percentage (14.80 and 12.00%), respectively in grain were little higher than the standard (<12%) in both BBS and untreated soil (control). In this study one can concluded that, the beer bio-sludge can improve both the physical & chemical properties of soil. Hence, BBS can serve as one of the best source of bio-fertilizers in the study areas and areas with similar agro-ecology zones.

Preliminary Findings on Cadmium Bioaccumulation and Photosynthesis in Rice (Oryza sativa L.) and Maize (Zea mays L.) Using Biochar Made from C3- and C4-Originated Straw

Understanding the structural differences between feedstocks is critical for biochar effectiveness in plant growth. To examine the efficiency of biochars with unique physiological structures in a cadmium (Cd)-polluted soil, rice and maize as C3 and C4 plants, as well as biochar generated from their residues, defined as BC3 and BC4, were utilized. The experiment involved a control and a Cd-polluted soil (20 mg kg−1) without biochar application, and applications of each type of biochar (20 t ha−1) on Cd-polluted or unpolluted soil. In rice and maize fields, BC3 application led to the highest value of cation exchange capacity (CEC), with increases of 162% and 115%, respectively, over the control, while CEC increased by 110% and 71% with BC4 in the rice and maize field, respectively. As compared to the control, BC3 and BC4 dramatically enhanced the photosynthetic rate (Pn) of rice by 116% and 80%, respectively, and maize by 67% and 31%. BC3 and BC4 significantly decreased the Cd transfer coefficient in rice by 54% and 30% and in maize by 45% and 21%. Overall, BC3 is preferred over BC4 for establishing rice and maize in Cd-polluted soil, as it has a lower C/N ratio, a considerably higher surface area, and more notable alkaline features such as a higher CEC and nutrient storage.

Removal of toluidine blue from water using 1:1 layered clay minerals

Extensive use of color dyes in modern society resulted in their potential release into the environment. Dye removal often involved in sorption or reaction. For sorptive removal, materials with low cost and high efficiency are of great potential. In this study, the removal of toluidine blue (TB), a cationic dye, by 1:1 layered clay minerals kaolinite (KAO) and halloysite (HNC) was systematically studied under different physicochemical conditions. The TB removal was fast and equilibrium could be reached within an hour. The TB removal capacities were 47 and 149 mmol/kg by KAO and HNC slightly larger than their cation exchange capacity (CEC) of 37 and 120 meq/kg. The results indicated that both the CEC and specific surface area (SSA) of the minerals played a critical role in TB removal. Equilibrium solution pH and ionic strength had less effect on TB removal, suggesting preferred affinity of TB over other inorganic cations for mineral surfaces. X-ray diffraction data showed no interlayer expansion, indicating TB sorption sites were on the external surfaces of both minerals. The FTIR results indicated participation of N+ on the dimethyl group for TB sorption on negatively charged mineral surface. At the sorption capacities, TB may form a condensed monolayer on KAO surfaces, and a dimer or bilayer coverage on HNC surfaces, as suggested by molecular dynamic simulation. The results from this study suggest that clay minerals of high CEC and large SSA values would be good candidates for the removal of cationic dyes form water.

Floating Rice Cultivation: a Solution to Reduce Crop Failure in Flood-Prone Areas

Bojonegoro is a regency in Indonesia located downstream of the Bengawan Solo River, a flood-prone area that caused crop damage and failure. The farmers need appropriate technology as an adaptation to reduce the loss of crop failure. Therefore, this study aims to determine the potential of floating rice cultivation as a solution for reducing crop failure. The experiment was arranged in Randomized Complete Block Design with two factors, namely planting media (soil:organic fertilizer (1:1) (M1); soil:rice husk (1:1) (M2); soil:organic fertilizer:rice husk (1:1:1) (M3)), and plant spacing (15 cm x 15 cm (J1); 20 cm x 20 cm (J2); 25 cm x 25 cm (J3)). Each unit treatment was replicated 3 times. The results showed M2J3 gave the best outcome on plant height of 94.3 cm, the tillers number of 21.7, and produced the highest rice yield of 14.16 tons ha-1. This treatment provides optimal soil conditions, high cation exchange capacity (CEC) of 26.6 cmol (+) kg-1, phosphorus availability (Av-P) 48.5 ppm, and potassium availability 0.9 ppm. The planting media compositions significantly affected soil cation exchange capacity, soil phosphorus availability, plant height, tillers number, and rice yield. The yield on floating rice cultivation was approximately similar when compared to the local farmer's fields. Floating rice cultivation can be used as a solution to reduce crop failure in flood-prone areas in Bojonegoro.

Native and alien grassland diversity respond differently to environmental and anthropogenic drivers across spatial scales

AbstractAimsTo identify environmental and anthropogenic drivers of alpha‐ and beta‐diversity for native and alien plant species.LocationRío de la Plata grasslands, South America (Argentina, Brazil and Uruguay; 27.3–39.1°S, 50.1–66.5°W).MethodsWe assembled a data set of 597 vegetation plots distributed across the Río de la Plata grasslands. To assess the drivers of native and alien alpha‐diversity (species richness), we performed a generalized least‐squares regression using environmental and anthropogenic predictors. We evaluated differences in beta‐diversity using Simpson's pairwise dissimilarity between pairs of plots and used multiple regression on distance matrixes to investigate environmental and anthropogenic drivers on compositional dissimilarity for both native and alien plant species.ResultsNative species richness was higher in sites with less demanding environmental conditions, such as lower precipitation seasonality and soils with higher cation exchange capacity. Numbers of alien species were positively related to soil pH, cropland density and road density and negatively to precipitation seasonality, mean temperatures and soil cation exchange capacity. The compositional dissimilarity was similar for native and alien species assemblages (mean ± SD: 0.64 ± 0.16 and 0.64 ± 0.35 respectively). Areas having similar climates and being geographically close shared more taxonomically similar assemblages, for both native and alien assemblages, while soil had disparate effects. Compositional dissimilarity of alien plants decreased with increasing road density.ConclusionsOur results highlight a grassland ecosystem where native species richness is still shaped only by environmental factors, but both sets of factors influence its composition. On the other hand, alien plants carry a strong signal of both environmental and human factors. As time progresses the number of alien species tend to increase, eroding the patterns of native biodiversity. To avoid this, efforts should be made to reduce road encroachment and the conversion of natural grasslands into croplands.

Ion exchange capacity of synthetic zeolite L: a promising way for cerium recovery.

The increasing rare earth elements' (REE) demand to meet the market request and the current political scenario show that it is essential to find good solutions to recover these elements from waste (both industrial and mining). Zeolites are microporous materials with high cation exchange capacity, up to now only little investigated for REE recycle. Here, we propose the use of NH4+-exchanged zeolite L for Ce recovery from a very diluted solution (0.002 M), mimicking the Ce3+ concentration of the liquors deriving from the leaching of spent catalysts. The aim of this work is twofold: (i) to investigate the exploitability of zeolite L as cation exchanger in the Ce recovery; and (ii) to determine the best working conditions. The investigated process consists of a coupled cation exchange: (1) in the first exchange the NH4+ cations - present in the zeolite porosities - are exchanged with the Ce3+ ions in the solution; and (2) in the second experiment, the Ce3+ trapped into the zeolite is recovered through a further exchange with NH4. The best working conditions for Ce3+ exchange of NH4-zeolite L are: batch system, liquid/solid ratio equal to 90 mL/g and 180 mL/g, 24 h of contact at 25 °C. The resulting Ce adsorption capacity (qt) is equal to ~25 mg/g and ~39 mg/g and the removal efficiency 100% and 77% for the two tested liquid/solid ratios, respectively. The kinetics was proved to be fast and consistent with industrial timing; no energy cost for temperature setting is required; and the acid pH (~4) of the solutions does not affect the zeolite structure stability and its exchange performance. It has been demonstrated that the zeolite framework is not affected by the exchange so that the same absorbent material can be employed many times.

Evaluate the role of biochar during the organic waste composting process: A critical review

Composting is very robust and efficient for the biodegradation of organic waste; however secondary pollutants, namely greenhouse gases (GHGs) and odorous emissions, are environmental concerns during this process. Biochar addition to compost has attracted the interest of scientists with a lot of publication in recent years because it has addressed this matter and enhanced the quality of compost mixture. This review aims to evaluate the role of biochar during organic waste composting and identify the gaps of knowledge in this field. Moreover, the research direction to fill knowledge gaps was proposed and highlighted. Results demonstrated the commonly referenced conditions during composting mixed biochar should be reached such as pH (6.5–7.5), moisture (50–60%), initial C/N ratio (20–25:1), biochar doses (1–20% w/w), improved oxygen content availability, enhanced the performance and humification, accelerating organic matter decomposition through faster microbial growth. Biochar significantly decreased GHGs and odorous emissions by adding a 5–10% dosage range due to its larger surface area and porosity. On the other hand, with high exchange capacity and interaction with organic matters, biochar enhanced the composting performance humification (e.g., formation humic and fulvic acid). Biochar could extend the thermophilic phase of composting, reduce the pH value, NH3 emission, and prevent nitrogen losses through positive effects to nitrifying bacteria. The surfaces of the biochar particles are partly attributed to the presence of functional groups such as Si–O–Si, OH, COOH, CO, C–O, N for high cation exchange capacity and adsorption. Adding biochars could decrease NH3 emissions in the highest range up to 98%, the removal efficiency of CH4 emissions has been reported with a wide range greater than 80%. Biochar could absorb volatile organic compounds (VOCs) more than 50% in the experiment based on distribution mechanisms and surface adsorption and efficient reduction in metal bioaccessibilities for Pb, Ni, Cu, Zn, As, Cr and Cd. By applicating biochar improved the compost maturity by promoting enzymatic activity and germination index (>80%). However, physico-chemical properties of biochar such as particle size, pore size, pore volume should be clarified and its influence on the composting process evaluated in further studies.

Antimicrobial potential of four mica drugs and their chemical and mineralogical properties

BackgroundMica drugs, a group of herbo-metallic traditional preparations comprising biotite mica as the major mineral ingredient, are prescribed for skin disorders and respiratory ailments and other chronic conditions in South Asian countries, particularly India and Sri Lanka. Mica-based drugs (Abhrak drugs) are subjected to unique and varied preparation procedures and the bioactivity of the drugs can be affected by drug-processing conditions, the ingredients used and the mica composition. The current study aimed to evaluate and compare, on the basis of their physical and chemical characteristics, the antimicrobial potential of two commercial mica drugs AbBb (Abhrak bhashma) and AbCh (Abhrak Chenhuram) and two mica drugs ABL1 (Abhrak Bhasma Laboratory Prepared 1) and ABL2 (Abhrak Bhasma Laboratory Prepared 2) prepared in the laboratory under different conditions.MethodsAntimicrobial activity of all four drugs was assessed at 10 mg/ml concentration against Pseudomonas aeruginosa, Escherischia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Candida albicans using well diffusion assay, agar dilution assay and Miles and Misra method. Major and trace metal constituents of the drug samples were measured using atomic absorption spectrometry. Mineralogical properties, bacteria-mineral interactions, morphological changes in microbes and the surface characteristics of the drugs were determined using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM).ResultsThe drugs ABL1, ABL2 and AbBh exhibited antimicrobial activity against only Gram-positive organisms (S. aureus and MRSA) when tested with Miles and Misra method (broth method). Mineralogical studies (XRD) revealed that biotite mica was altered into secondary clay minerals and iron oxides in the commercial drug AbCh while the other three drugs had altered mica and iron oxide phases. The essential elements (Na, K, Ca and Mg) required for microbial functions were present in varying extents in all four drugs while they were present in exceedingly high amounts in AbCh having comparatively high cation-exchange capacity, consistent with the observation that AbCh was inactive against all the microbes tested. The three drugs (ABL1, ABL2 and AbBh) showing antimicrobial activity contained comparatively high amounts of Fe, Zn and Cu that are known to display antimicrobial properties at high concentrations. SEM studies revealed that the drug particles adhered and entrapped the bacterial species, presumably modifying the physiochemical characteristics of the bacteria and eventually causing lethality.ConclusionThree of the four mica drugs inhibited the tested Gram-negative bacteria and the antibacterial activity of the mica drugs depends on their constituents and the methods of preparation.