The adsorption of methylene blue in an aqueous medium using two activated carbons AC1 and AC1 + H3PO4 was studied. The AC1+ H3PO4 adsorbent, which was inoculated with phosphoric acid, had better methylene blue removal capacity compared with AC1 adsorbent which had only thermal treatment. The optimum activation temperature for both adsorbents was 500°C while the suitable activation time was 180 min. The best pH in this investigation was 6. With AC1 + H3PO4 adsorbent, 100% removal of methylene blue was recorded for concentrations 20 to 100 mg.L-1 and the suitable adsorbent dosage was 3 g.L-1. The effect of temperature showed insignificant effect on the adsorption of methylene blue ions. The SEM results for AC1 + H3PO4 adsorbent showed better pores compared with AC1, an indication that the injection of phosphoric acid into it before the activation played a significant role in enhancing the porosity of the adsorbent surface.

Marine litter and associated marine pollution are becoming a complex global environmental hazard these days. Among the different faces of marine pollution, by far the largest and probably the most dangerous part is marine plastic litter. Plastic litter can be found in almost every marine environment in the world, including deep ocean beds and frozen polar ice. Unless new sustainable methods of plastic production and waste management are encouraged, marine plastic pollution will continue to pose a severe threat to the natural ecosystems of the world. In this paper, the status of marine plastic litter is reviewed using a DPSIR framework, and it is found that significant changes in the way we live and consume are needed to prevent it. A framework that combines the source-to-sea approach and circular economy is introduced as a possible solution to eliminate plastic waste from the environment as well as from the economy.

In this study, the microbial population responsible for decomposition of banana leaf with dung and urine of cattle (cow and sheep used here) was isolated, identified, and their incidence calculated. During this study, significant changes were observed in different physio-chemical properties (temperature, pH, moisture content, humidity, ash content, total organic carbon, total nitrogen content, phosphorus) of decomposing material which focuses particularly on the role of thermophilic coprophilous fungi in reducing the time for decomposition. It also gives a clear demonstration of various effects of different environmental conditions on the microbial population during the process of decomposition. The decomposition product thus obtained was found to be rich in organic phosphorous and nitrogen, raising our hopes for a successful implementation of it in daily agricultural practices.

One of the challenges for hydropower dam operation is the occurrence of supersaturated total dissolved gas (TDG) levels that can cause gas bubble disease in downstream fish. Supersaturated TDG is generated when water discharged from a dam entrains air and temporarily encounters higher pressures (e.g. in a plunge pool) where TDG saturation occurs at a higher gas concentration, allowing a greater mass of gas to enter into solution than would otherwise occur at ambient pressures. As the water moves downstream into regions of essentially hydrostatic pressure, the gas concentration of saturation will drop, as a result, the mass of dissolved gas (which may not have substantially changed) will now be at supersaturated conditions. The overall problem arises because the generation of supersaturated TDG at the dam occurs faster than the dissipation of supersaturated TDG in the downstream reach. Because both generation and dissipation of TDG are functions of water temperature, there is an opportunity to affect the TDG process through selective withdrawal structures at a reservoir. Using a combination of field observations, and hydrodynamic modelling, we analysed the dependence of the water temperature difference on TDG generation from different-elevation release structures of highdam reservoirs. By using of the dissipation model coupled with TDG and temperature, the evolution of supersaturated TDG from different withdrawal structures was simulated and compared in a natural river reach. It showed that warmer withdrawals result in reduced generation of TDG and enhanced dissipation of TDG.

A new adsorbent modified from orange peel (OP) was successfully synthesized by ethylenediamine crosslinking method to remove Cr(VI) from wastewater. The modified orange peel powder (MOPP) was investigated in a batch adsorption system, including both equilibrium adsorption isotherms and kinetics. Effects of several factors, including adsorbent dose, initial pH and Cr(VI) concentration were studied. The data indicated that the pH was not an essential factor that affected the adsorption process, it has a wide pH range from 4 to 10, and high adsorbent dose and lower Cr(VI) concentration could increase the Cr(VI) removal efficiency. Equilibrium data were analysed using the Langmuir, Freundlich and Temkin isotherm models and found to be well represented by the Langmuir isotherm model. The maximum capacity (qmax) obtained from Langmuir model was 52.08 mg/g at pH 6.0. The kinetics of adsorption followed the pseudo-second-order kinetic equation. The results suggest that MOPP is an inexpensive and efficient adsorbent for removing Cr(VI) from aqueous solution.

The inhibitive properties of the extracts of Cascabela thevetia and Jatropha curcas were comparatively studied on corrosion of mild steel in H2SO4 acid. The extracts of both plants contained active phytochemical constituents such as tannins, saponins, alkaloids, flavonoids, terpenes and phenols which made them useful as good corrosion inhibitors. The extract concentrations were varied from 0.3 to 1.5 g/L during both the gravimetric and gasometric analyses for an exposure time of 7-28 days. The weight loss of the coupon, corrosion rate, surface coverage and inhibitive efficiency was evaluated for both the extracts. The results of the gravimetric and gasometric analyses indicated that inhibitive efficiency increased with an increase in the concentration of inhibitors and the highest was 55.77% for Jatrophas curcas at the concentration of 1.5 g/L. The weight loss was a little lower for Cascabela thevetia (4.36 g) compared to Jatrophas curcas (4.66 g) at the highest exposure time used (28 days). Cascabela thevetia has a better surface coverage (0.68) than Jatropha curcas (0.61), hence, Cascabela thevetia inhibits better for a 7-day exposure time. However, when the mild steel was further exposed for more than 7 days, Jatropha curcas exhibited a better inhibitive property. The highest and least hydrogen gas evolution was obtained at 0.3 g/L concentration (7 minutes) and 1.5 g/L concentration (1 minute) for both Cascabela thevetia and Jatropha curcas leaves extracts, respectively. Based on the results, the utilization of extracts of Cascabela thevetia and Jatropha curcas leaves as replacements for toxic organic inhibitors in industries are recommended.

Innovative development of a simple and rapid dispersive micro solid phase extraction (D-?-SPE) method combined with high performance liquid chromatography (HPLC) based on alginate incorporated with multi-walled carbon nanotubes (Alg-MWCNT) was developed for the analysis of five selected acidic drugs in the water sample. The effect of dispersive micro solid phase extraction parameters such as the mass of sorbent, sample pH, extraction time and desorption time on the peak area of analytes were optimized. Under the optimum extraction conditions, a linear response was achieved in the concentration range of 1 ?g.L-1 to 500 ?g.L-1 (R2 ? 0.9959). The limits of detection for the method at a signal to noise ratio of 3 were between 0.03 ?g.L-1 and 0.08 ?g.L-1. The proposed method was successfully applied for the determination of four acidic drugs in tap water samples with relative recoveries ranging from 75 % to 105 %. The proposed Alg-MWCNT sorbent showed high potential as an alternative sorbent for dispersive micro solid phase extraction of acidic drugs in aqueous matrices.

An experiment was carried out to appraise the effect of seed priming treatment with Mg(NO3)2 against various levels of externally imposed moisture stress by polyethylene glycol-6000 on phytotoxicity in shoot and root and chlorophyll content in maize plant under laboratory conditions. The phytotoxicity of shoot and root was increased as the elevated levels of PEG-6000 towards T1 to T4 (i.e. 1.5 to 4.5 %, Set-I) as compared to control set (T0, i.e. without treated set), while the least values of phytotoxicity were recorded in T5 and onwards increased slowly up to T8 (i.e. 1.5 to 4.5 % of PEG-6000 + primed seed, Set-II). The same trend of phytotoxicity was recorded for both the plant parts at both the times of observations, i.e. shoot and root 120 and 240 hours. The chlorophyll content of shoot was recorded in decreasing trend onwards from T1 to T4 in treatment set-I as compared to T0, i.e. control. While the highest amount of chlorophyll content was recorded in T5 followed by T6 as compared to the rest of the treatments.

The considerable increase in the amount of nitrogen in the surface water is a major environmental problem. It has become a great matter of worry because of the multiple environmental effects including eutrophication and health risks. The El-Kebir West watershed is a coastal plain in northeastern Algeria.This study aims to determine the physicochemical quality of waters of the western WadiEl-Kebir and its main tributariesand also to evaluate the spatiotemporal variabilityof its physicochemical quality in particular of mineral nitrogen during wet and dry periods. Four sampling campaigns were realized as follows: January 2015 and February 2016 corresponding to water high season and in March and September 2016 corresponding to the low season. The water samples were obtained from the seven stations located along western Wadi El-Kebir. Temperature, pH,conductivity,dissolved oxygen,SO42-, PO43-, NO3-, NO2-and NH4+ were measured either in situ or in the laboratory.A statistical treatment employingthe PCA method (The Principal Components Analysis) was applied for all the obtained results. It has been noticed that the S2 and S3 upstream stations are very rich in ammonium (NH4+) at the low water period with average values of 15.22 mg/L and 20.41 mg/L, respectively.This study has shown the influence of seasonal variations and anthropogenic activities on the evolution of physicochemical settings, in general, and on mineral nitrogen in particular. In conclusion,the waters of Wadi El-Kebir were of an average to poor quality.

This study reports the results of an analysis performed on 40.5 km stretch of River Tungabhadra. The results show that there was a significant increase in all the physical and chemical variables of the river towards downstream of Harihara town, particularly in the pre-monsoon season. However, all the variables remain within the standards recommended for drinking water. Based on the Central Pollution Control Board (CPCB) guidelines, the classification of water at various segments of the research focal area is as follows: the 12.08 km stretch from the upstream boundary (Ingalagondi) is designated as class C, based on the Biochemical Oxygen Demand (BOD). However, from 12.08 km to 40.5 km on the stretch of downstream Harihara is designated as Class D, based on the BOD. However, in terms of dissolved oxygen (DO), the river satisfies the requirements for Class C (> 4 mg/L) at all of the locations sampled across all periods.