Lantana camara, an invasive species that adversely affects habitant, bioregions and environment has been studied as corrosion inhibitor. Methanolic extract of barks of Lantana camara in 1 M hydrochloric acid was tested as corrosion inhibitor on mild steel using potentiodynamic polarization technique. The corrosion inhibition efficiency of extract varied with concentration of extract and immersion of time. The inhibition was found to increase with increase in concentration of the extract. The polarization behavior of mild steel revealed that maximum inhibition efficiency is 97.33 % and 89.93 % respectively in the 1000 and 200 ppm concentration of the inhibitor respectively. The results showed that the extract of the barks of Lantana camara served as a mixed type inhibitor.

Limestone is principal raw material for cement making industries. Chemical composition of limestone plays great role for making good quality cement. Production of good quality cement is of primary importance for the increment of the durability of infrastructure. Nepal is establishing large number of cement industries that uses limestone as raw materials and it is urgent to determine the quality of limestone. Quantitative Chemical analysis of one hundred forty three (143) limestone samples, collected by the channel sampling method, is carried out using gravimetric, titrimetric, and atomic absorption spectroscopic methods. The determined values of different parameters in percentages are as follows; loss on ignition (41.96385±0.670325), acid insoluble matter (2.412308±1.014588), Fe2O3 (0.263846±0.082249), Al2O3 (0.765385±1.656052), CaO (52.20538±1.656052) and MgO (3.018462±0.703886). The results indicated that most of the limestone samples are found to meet industrial raw material specifications for some industries. They can be used in the cement, agriculture (liming of soil and fish ponds) and metallurgical purification processes in the steel industry. Collected limestone samples meet the raw material specification of some industries. So establishment of such industries from a chemical point of view is feasible.

Two different types of alkaloids are successfully extracted from two plants Artemisia vulgaris (AV) and Solanum tuberosum (ST) in the laboratory and used as corrosion inhibitors for mild steel samples. The corrosion inhibition potential of these alkaloids is determined by weight loss and potentiodynamic polarization measurement methods. Based on the weight loss measurement study of a sample immersed for 6 h in 1000 ppm inhibitor solution of AV and ST alkaloids, the corrosion inhibition efficiency is found to be 92.58% and 90.79%, respectively. The potentiodynamic polarization measurement shows 88.06% and 83.22% corrosion inhibition efficiency for AV and ST alkaloids, respectively, for the sample immersed for 1 h in 1000 ppm inhibitor solution. These promising efficiency and suitable immersion time effect can lead to the development of good green inhibitors.

The goal of this study is to develop charred tea waste (CTW) via chemical process for the removal of Cr(VI) from contaminated water. Batch adsorption experiments were conducted as a function of pH, initial concentration, contact time and adsorbent dosage. Characterization of the adsorbent was analyzed by FT-IR and XRD. Maximum adsorption capacity (qm) of the CTW was found to be 85.32 mg/g at optimum pH 2 in 120 minutes. The adsorption on CTW was well fitted to the Langmuir isotherm and the kinetic data is consistent with the pseudo-second order kinetic model. The findings suggest that CTW could be an efficient and promising adsorbent for the removing Cr(VI) from aqueous solution.

Alkaloids as green inhibitors were extracted from three different plants Rhynchostylis retusa, Artimesia vulgaris,and Solanum tuberosum. Weight loss measurement in mild steel has been carried out in the presence and absence of green inhibitors individually in an acidic medium. Weight loss measurements at different temperatures are used to calculate thermodynamic parameters. The weight loss measurements at different concentrations are used to find adsorption isotherm and found that it obeys Langmuir adsorption isotherm with R2 values 1, 1, 0.996 for three inhibitors. Activation energy, enthalpy, and entropy of the three inhibitors have been calculated. It is found that the value of all these parameters increased in the addition of inhibitors. The free energy of the system is calculated and found (-17.46 kJ mol-1) indicating that the adsorption process is spontaneous and there is physical adsorption at the MS-Inhibitor interface.

Technological advancement is accompanied by excessive consumption of fossil fuels and affluent uses of chemical substances in many sectors, including transportation and manufacturing companies, and so on. Being an exhaustible resource, the excessive use of fossil fuels and of chemical substances may lead to a serious energy crisis in the long run, and it may additionally impose environmental pollution. Attempts have been made in the solution of such serious issues from every nook and corner. Nonetheless, no method has been found to be a panacea in waste water treatment and subsequent beneficiaries. One of the attempts in the solution to such issues is the application of photocatalytic technology, which could serve as a dual function in environmental remediation and clean energy production. A photocatalytic fuel cell is a tool developed for the recovery of energy from organic wastes. A rational cell construction needs the fabrication of photoelectrodes, the design of a photoanode and a photocathode chamber, in addition to an ion-transport membrane for pollution treatment and electricity generation. In this review, comprehensive fundamental assessments and recent developments in the design of photocatalytic fuel cells, their applications, future prospects, and challenges are covered.

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