Fixed-Bed Adsorption of Phenol onto Microporous Activated Carbon Set from Rice Husk Using Chemical Activation

In the course of this research, the potential of activated carbon from rice husk was examined as being a phenol removal medium from an aqueous solution in a fixed-bed adsorption column. The activated carbon was characterized through FESEM (Field-Emission Scanning Electron Microscopy) and BET (Brunauer–Emmett–Teller) surface area. According to the FESEM micrograph and BET surface area, RHAC (rice husk activated carbon) had a porous structure with a large surface area of 587 m2·g−1 and mean diameter of pores of 2.06 nm. The concentration effects on the influent phenol (100–2000 mg·L−1), rate of flow (5–10 mL·min−1), and bed depth (8.5–15.3 cm) were examined. It was found that the capacity of bed adsorption increased according to the increase in the influent concentration and bed depth. However, the capacity of bed adsorption decreased according to the increase in the feed flow rate. The regeneration of activated carbon column using 0.1 M sodium hydroxide was found to be effective with a 75% regeneration efficiency after three regeneration cycles. Data on adsorption were observed to be in line with many well-established models (i.e., Yoon–Nelson and Adams–Bohart, as well as bed depth service time models)

Fixed-Bed Adsorption of Phenol onto Microporous Activated Carbon Set from Rice Husk Using Chemical Activation

In the course of this research, the potential of activated carbon from rice husk was examined as being a phenol removal medium from an aqueous solution in a fixed-bed adsorption column. The activated carbon was characterized through FESEM (Field-Emission Scanning Electron Microscopy) and BET (Brunauer–Emmett–Teller) surface area. According to the FESEM micrograph and BET surface area, RHAC (rice husk activated carbon) had a porous structure with a large surface area of 587 m2·g−1 and mean diameter of pores of 2.06 nm. The concentration effects on the influent phenol (100–2000 mg·L−1), rate of flow (5–10 mL·min−1), and bed depth (8.5–15.3 cm) were examined. It was found that the capacity of bed adsorption increased according to the increase in the influent concentration and bed depth. However, the capacity of bed adsorption decreased according to the increase in the feed flow rate. The regeneration of activated carbon column using 0.1 M sodium hydroxide was found to be effective with a 75% regeneration efficiency after three regeneration cycles. Data on adsorption were observed to be in line with many well-established models (i.e., Yoon–Nelson and Adams–Bohart, as well as bed depth service time models)

Analyzing the Spatial Correspondence between Different Date Fruit Cultivars and Farms’ Cultivated Areas, Case Study: Al-Ahsa Oasis, Kingdom of Saudi Arabia

Diversity in date palm (DP) cultivars plays a crucial role in the agroecosystems of several countries, such as the Kingdom of Saudi Arabia (KSA). This study aims to map and analyze the spatial distribution of the most grown DP cultivars (Khlas, Ruziz, and Shishi) in the Al-Ahsa oasis in the KSA and to highlight their spatial correlation with the corresponding cultivated patches within farms. Descriptive and spatial data on 288 farms were analyzed using GIS, data curation, cross-TAB statistics, clustering maps, and spatial autocorrelation techniques. The obtained results revealed that most of the oasis’s DP farms are within a cultivated area of <500 m2. The larger cultivated areas are mostly in the oasis’s northern and central subregions, agreeing with the spatial distribution of trees. In total, 56.9% of the studied farms grew the cultivars together within the least rank (<500 m2) of cultivated area, having the greatest tendency for DP cultivation. Khlas was the most dominant cultivar being the least absent from cultivation with 3.1% compared to Ruziz (31.9%) and Shishi (37.8%). The spatial distribution of DP plantations in the oasis was also consistent with the spatial variation in soils and irrigation water salinity, necessitating the need for special agricultural extension programs. In conclusion, these outcomes indicate that this study is essential for DP sustainability, growers, authorities, and policy makers

Analyzing the Spatial Correspondence between Different Date Fruit Cultivars and Farms’ Cultivated Areas, Case Study: Al-Ahsa Oasis, Kingdom of Saudi Arabia

Diversity in date palm (DP) cultivars plays a crucial role in the agroecosystems of several countries, such as the Kingdom of Saudi Arabia (KSA). This study aims to map and analyze the spatial distribution of the most grown DP cultivars (Khlas, Ruziz, and Shishi) in the Al-Ahsa oasis in the KSA and to highlight their spatial correlation with the corresponding cultivated patches within farms. Descriptive and spatial data on 288 farms were analyzed using GIS, data curation, cross-TAB statistics, clustering maps, and spatial autocorrelation techniques. The obtained results revealed that most of the oasis’s DP farms are within a cultivated area of 2. The larger cultivated areas are mostly in the oasis’s northern and central subregions, agreeing with the spatial distribution of trees. In total, 56.9% of the studied farms grew the cultivars together within the least rank (2) of cultivated area, having the greatest tendency for DP cultivation. Khlas was the most dominant cultivar being the least absent from cultivation with 3.1% compared to Ruziz (31.9%) and Shishi (37.8%). The spatial distribution of DP plantations in the oasis was also consistent with the spatial variation in soils and irrigation water salinity, necessitating the need for special agricultural extension programs. In conclusion, these outcomes indicate that this study is essential for DP sustainability, growers, authorities, and policy makers

Danau Sentarum national park: the abandoned paradise

Danau (Lake) Sentarum is one the most unique wetlands in Asia, marked by outstanding biodiversity. This area was declared as a national park in 1999, covering 132,000 hectares. The park is located in the upper Kapuas district, which declared itself a conservation district in 2003. What’s the current condition of the park? Who manages and who owns it? And how’s the condition of the people who have been living in this area for hundreds of years? This movie is dedicated to the local people of Danau Sentarum and to those who are trying to save it. Establishment of the national park and the conservation district requires some supporting conditions to achieve the goals

Seasonal dynamics of surface energy fluxes over a center-pivot irrigated cropland in Saudi Arabia

Aim: This study focused on the seasonal dynamics of energy fluxes over selected agro ecosystems (alfalfa and corn crops) to understand the role of energy partitioning in determining the mechanisms controlling the crop water requirement and irrigation schedules. Methodology: Eddy Covariance (EC) flux tower was installed on a center pivot irrigated field located in the Eastern Region of Saudi Arabia. EC data of nearly three years (May 2013 to March 2016) was analysed for variations in agro-climatic conditions, energy fluxes and their partition under both cropped (alfalfa and corn) and non - cropped ( fallow ) scenarios. Results: Three-year mean net radiation (R ) varied from 106.8 to n 816.54 Wm-2, while the recorded sensible heat, soil heat (G) and latent heat fluxes were 291.6, 158 and 3.8 Wm-2, respectively. The latent heat was more during the crop growing season (381.38 W m-2) compared to fallow (23.89 W m-2); while, sensible heat showed an opposite trend compared to latent heat. The sensible heat recorded during the growing season (38.42 W m-2) was much lower than for the fallow season (281.35 W m-2). Interpretation: There was contrasting variations in sensible heat and latent heat fluxes across seasons and corresponding to the changing climate and surface conditions of the field. In the case of silage corn, the proportions of partitioned energy to sensible heat (12.4%) and latent heat (18%) were higher than alfalfa. However, during the alfalfa post-harvest practices, the latent heat flux was always less as the available energy was partitioned as sensible heat rather than latent heat flux

The water footprint (WF) of silage maize and carrot crops.

<p>The water footprint (WF) of silage maize and carrot crops.</p

Methodological flowchart—Water Footprint of crops from remote sensing data and empirical approach.

<p>Methodological flowchart—Water Footprint of crops from remote sensing data and empirical approach.</p

Season and crop wise length of the growth period (lgp) and K_c values (given in parenthesis) taken from [32].

<p>Season and crop wise length of the growth period (lgp) and K_c values (given in parenthesis) taken from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0192830#pone.0192830.ref032" target="_blank">32</a>].</p