Global NEST Journal

In this research the arsenic contaminations issues are exposed and suitable measures are recommended through electrokinetic remediation. The arsenic expulsion was assessed using the electro kinetic remediation from two different soil tests; alluvial clay soil and red clay soil taken from the Tamilnadu zone. Three distinct cathodic electrolytes—deionized water (DIW), potassium phosphate (KH2PO4), and sodium hydroxide—were used to test the viability of upgrading experts (NaOH).The consequences of the examinations on the alluvial mud soil shows that the potassium phosphate (0.1N) was the best in extricating arsenic (79.5% removal efficiency), likely because of anion trade of arsenic species by phosphate. Then again, the sodium hydroxide (0.1N) appeared to be the most proficient in with eliminating arsenic (63%) from the red soil. The sodium hydroxide's ability to increase soil pH and hasten the ionic migration of arsenic species through the desorption of arsenic species as well as the disintegration of arsenic-bearing minerals may help to explain and suggest this result. In order to forecast the effectiveness of removing arsenic from polluted soil, studies using response surface technique are also designed using the Box Behnken Method.

Oil Palm Kernel Shell (OPKS) is a residue of the palm oil extraction process, which has good characteristics for the production of activated carbon (AC). Colombia ranks fourth in the world in palm oil production and it is estimated that in 2019 the amount produced of OPKS was approximately 336000 ton per year. Within the contaminants of surface waters, the pesticide paraquat is identified as one of the most dangerous for human health and is at the same time one of the most used in agriculture in Colombia. It is found worldwide in natural waters in the range of 50 µg/l to 5000 µg/l. Oil palm kernel shells were first carbonized in a horizontal oven under N2 atmosphere until 850 °C for 30 min. After that, three batches, each of 300 g of the carbonized OPKS (COPKS) were activated in the same horizontal reactor by means of partial gasification using H2O as reaction agent. The activation process starts with a heating stage by raising the temperature from 20 °C to 850 °C in approximately 280 minutes under a N2 atmosphere. Then in the activation stage the flow of N2 is replaced by a flow of 20,68 l/min steam while maintaining the temperature at 850 ± 10 °C for another 310 minutes. Finally, the flow of steam is changed to N2 and the oven is cooled down until ambient temperature. As a result of the activation process, an activated carbon (AC-CAC) with approximately 50 % degree of activation and a surface area of 1200 m2/g were obtained. The adsorption capacity of the AC-CAC towards paraquat is studied by measuring breakthrough curves in an adsorption column using initial concentrations of paraquat between 600 µg/l and 5000 µg/l. A comparison is performed by using a commercial activated carbon CAC from the company Donau Carbon ref. Hydraffin®. The determination of the concentration of paraquat in water is made by voltammetry.

Soil was familiar earlier in the context of agriculture and food production, but industrialization contaminated soils around the world in last two centuries. Most of the contamination is due to the consequence of improper discharge of industrial wastewater and one such situation is witnessed in the agricultural land nearby textile hub of Tiruppur, Tamil Nadu in Southern India. It is essential to identify the contaminants depth in soil system before propose any in-situ remediation technique. There is no study reported so far to understand the transport and fate of organic and inorganic contaminants of textile wastewater in soil system. This paper investigates the transport and fate of textile wastewater in soil column of 32 cm height and 8 cm diameter. Detailed investigation demonstrates the removal of color 15-84%, organic contaminants 4-51% and inorganic contaminants 11-36% from wastewater after its transport into the soil. The reduced level of calcium, magnesium and potassium ions in soil and corresponding increase in wastewater reveals anion and cation exchange between wastewater and soil. Thus the results confirm the accumulation of residual textile dyes and inorganic salts in the soil and it is huge in surface soil of 0-15 cm depth, further it requires immediate restoration.

In the present work, the potential of cumnium cyminum as an effective bio adsorbent for the removal of cationic dye (Red 95) was investigated. Batch adsorption experiments were carried out to investigate the effects of adsorbent dosage, pH and contact time with initial dye concentration on adsorption. In connection with adsorbent dosage the highest removal efficiency was 143.64mg/L of removal efficiency 88.36%, regarding pH study the peak removal attained with 141.37mg/L with the removal percentage 86.76% and for contact time study the removal efficiency attained in the concentration of 142.10mg/L in the removal percentage of 87.41%. The adsorption studies demonstrated that the Thomson model, and Yoon nelson model are excellent descriptions of adsorption processes. The maximum adsorption capacity of 143.64 mg/L toward biosynthesized nano adsorbent with removal rates of 88.36% and greatest R2 value of around 0.9879 was well suited to the equilibrium data. The ANOVA was used for the analysis of variance to determine the best parameters for the overall adsorption model. Utilizing SEM, XRD, and FTIR methods, the adsorbent was characterized. Different desorbing agents, such as NaOH, HCl, and NaCl, were examined for the desorption of cationic dye (Red 95) loaded with adsorbent generated from cumnium cyminum, and it was shown that HCl was the most effective desorbing agent when combined with deionized doubly distilled water (DDDW). The proportion removal of cationic dyes was improved with increasing adsorbent dose and contact time and the percent of color exclusion was decreasing with increasing pH.