Study of the Iron Behavior in Acid Rain Water Solution by Application of Two Green Corrosion Inhibitors

The corrosion of iron in an acidic medium similar to acid rainwater (pH = 3.6) at various rotation speeds was investigated. The investigation included the inhibiting effect of two new green formulations containing oils extracted from the seeds of Jatropha curcas (labeled JAC) and Aleurite moluccana (labeled ALM). The inhibition efficiency was evaluated using electrochemical measurements, after performing an automatic ohmic drop compensation (ZIR). The results obtained show that an increase in the rotation speed leads an increase in the current density (from 75.57 µA/cm2 at 0 rpm to 99.09 µA/cm2 at 1500 rpm). This increase can be explained by the increase in the amount of dissolved oxygen at the electrode surface in the acidic rain solution (pH = 3.6). Also, the two environment-friendly corrosion inhibitors both act as mixed type inhibitors that protect iron against corrosion in the acidic solution. The inhibition efficiency increases with an increase in the inhibitor concentration to attain a maximum of 97% and 96% at 250 ppm of the ALM and the JAC, respectively.

Analisis kimia dan kualitas air hujan di Kota Palu sebagai penyebab terjadinya hujan asam

Acidic compounds such as sulfur dioxide (SO2) and nitrogen oxides (NOx), which are generally emitted into the atmosphere by human activities from burning fossil fuels, motor vehicles and industry, react with water and oxygen to produce acidic rain that falls to the earth's surface. This study aims to investigate the quality of rainwater chemical compounds at the Mutiara Palu Meteorological Station using 282 samples derived from the BMKG Air Quality Database during February 1993 – January 2020. The method used are descriptive analysis and correlation analysis to determine the relationship between chemical compound reactions that occur in the rainwater in Palu City. The results showed that the chemical compounds in rainwater in Palu City were dominated by strong acid compounds in the form of Cl-, SO42-, and NO3- compounds with a percentage of 63% and the most dominant quality was in the acidic rain category with a pH value below 5.6, as much as 55.7%. Chemical compounds contained in rainwater in Palu City are mineral compounds that originated from natural form of minerals, particularly from sea salt. The relationship between chemical compounds contained in rainwater has varied values and is in the low to moderate category. In general, the results indicate that the quality of rainwater in Palu City is low and not recommended for health and the environment.

Functional Nano-Hydroxyapatite for Applications in Conservation of Stony Monuments of Cultural Heritage

Stony monuments must continuously be safeguarded from damage caused over time, in particular from the detrimental effects of weathering. One of the new environmentally-friendly (nano) materials for stone reinforcement, particularly suitable for marble and calcareous (limestone, sandstone) artifacts, is Ca10(PO4)6(OH)2 hydroxyapatite (HAp), which has a considerably lower dissolution rate and solubility compared to CaCO3 calcite (the building block of marble materials): thus, HAp has been proposed for the protection of calcareous monuments against acidic rain corrosion. Promising results have been obtained, but further optimization is necessary as the treated layer is often incomplete, cracked and/or porous. Several parameters need to be optimized, in this way a homogeneous layer can be obtained, and consequently the formation of metastable can be avoided, soluble phases instead of HAp. These include: the pH of the starting solution; the effect of organic and inorganic additions in particular, that of ethanol, which is known to adsorb calcite, thus possibly favoring the growth of the HAp layer. The formation of HAp nanoparticles and their application on stony substrates has been investigated by means of a multi-methodological approach based on scanning electron microscopy, x-ray diffraction, small- and/or wide-angle x-ray scattering, Fourier-transform infrared spectroscopy, and finally, in situ measurements of laser-induced breakdown spectroscopy and acid attack preliminary tests on stony substrates.

Leachate Analysis of Heavy Metals in Cigarette Butts and Bricks Incorporated with Cigarette Butts

Billions of cigarette butts (CBs) are discarded as litter in the environment every year worldwide. As CBs have poor biodegradability, it can take several years for them to break down while leaching toxic chemicals and heavy metals. Mohajerani et al. (2016), based on long-term research, developed a method for the recycling of CBs in fired clay bricks with promising results. This paper presents and discusses the leaching behavior of potentially hazardous metals from used, unused, and shredded used CBs, and unfired and fired clay bricks incorporating CBs. The leachate analysis was conducted according to the Australian Bottle Leaching Procedure (ABLP) for pH values 2.9, 5.0, and 9.2. The aim was to quantify the amount of heavy metals leached, determine the relationship between the metal concentration leachate, pH of the solution and condition of the sample, and examine the effect of firing on the leaching capability of bricks. The leachate results were then compared to the concentration limits for heavy metals set by the United States Environmental Protection Authority (USEPA) national primary drinking water and the Environmental Protection Authority (EPA) solid industrial waste hazard categorization thresholds to assess the suitability of fired clay bricks incorporating CBs. Metals Cu, Zn, Mn, Al, Fe, Ti, and Ba demonstrated the highest leachate concentrations for pH 2.9 and pH 5.0 for used CBs. This suggests that used CBs are more prone to leaching heavy metals in areas with highly acidic rain compared to the natural range of precipitation. The leaching behavior of fired bricks incorporating CBs was considerably lower than that for the unfired bricks due to the immobilization of heavy metals during the firing process. However, the leaching of Cr and Ni was almost completely impeded after the firing of the bricks, and more than 50% of all the tested heavy metals were hindered.

Comparison of Degradation of Concretes with High Portions of Mineral Additions and Ordinary Portland Cement Based Concretes due to Simulated Acidic Rain

The paper deals with investigation of changes in selected properties of concretes which have been exposed to acid rain. The experiments took place in laboratory under model solution representing acid rain (40 % HNO3, 60% H2SO4) over a period of 7 weeks. The concrete samples investigated were concretes with ordinary Portland cement only as well as concretes of high-portion-mineral-addition-cements as well. Disruptions, cracking and samples' falling apart at the end after 7-week exposure to acid rain were observed by evaluation of visual changes. Based on the determination of the other parameters the results are not so uniform that is why the clear statement of more suitable concrete resistant to acid rain is not given. The assumption that a high-mineral concrete mix would be more suitable for environments exposed to acidic rain was not confirmed in this experiment.

Biochar Remediation Improves the Leaf Mineral Composition of Telfairia occidentalis Grown on Gas Flared Soil

This study evaluates the effects of remediation of gas flared soil by biochar on the nutritional composition of cultivated Telfairia occidentalis leaves, relative to non-gas flared soil. Gas flared soils are degraded due to the presence of heavy metals, noxious gases, carbon soot and acidic rain. Biochar produced from oil palm fibre was applied at five different amounts: 0 t ha−1, 7.1 t ha−1, 13.9 t ha−1, 20.9 t ha−1 and 28.0 t ha−1 to containerized soils (both gas flared and control soil), inside a greenhouse, which were allowed to mineralize for two weeks. Two viable seeds of T. occidentalis per replicate were sown. After eight weeks of growth, leaves were harvested, dried and chemically analyzed. Application of biochar significantly increased leaf ash and crude fibre content of Telfairia occidentalis. Plants from soil treated with 13.9 t ha−1 of biochar had the highest concentrations of vitamins A, B1, B2, B6, C and E irrespective of soil type. Maximum increase in leaf vitamin and mineral content was obtained from leaves cultivated on gas flared soil treated with 13.9 t ha−1 and 7.1 t ha−1 of biochar respectively. The results show that biochar treatment can increase leaf mineral concentrations and that this effect is dependent on the amount of biochar application.

Trends in urban storm water quality in Tallinn and influences from stormflow and baseflow

Temporal trends provide a good interpretation of change in stormwater quality over time. This study aimed to analyse trends and influences due to stormflow and baseflow. Grab samples of 18-19 years from 1995 to 2014 recorded at outlets of 7 Tallinn watersheds were analysed for monotonic trend through seasonal Mann Kendall test for long-term, short-term, baseflow and stormflow. Statistically significant downward trends (P-value (p) < 0.05) were found for 6 – hydrocarbon (HC), 1 – suspended solids (SS), 3 – biological oxygen demand (BOD), 4 – total nitrogen (TN) and 2 – total phosphorus (TP) out of 7 sampling outlets over the last 10 years. Less significant decreasing trends (p > 0.05 and < 0.2) for 3 – SS, 1 – BOD, 1 – TN and 1 – TP were identified. Statistically significant long-term upward trends of pH were re-vealed in 5 basins, which reduced to 2 with 5 less significant upward trends over the 10 year period, indicating improve-ments in pH reduction. Härjapea has the highest pH without trend but it includes an upward trend of TN at p = 0.051. The highly possible causes for downward trends are street sweeping, sewer network improvement, decline in sub-urban agri-cultural areas, etc. The upward trend results of pH are related to increased alkalinisation due to acidic rain, weathering of carbonate rocks, sewage discharge and alkaline road dust. In most of the basins, stormflow has more influence on trends than baseflow.

DURABILITY OF THE PAINTED RENDERED FACADES, WHEN INTRODUCING ARTIFICIAL ACIDIC RAIN SOLUTION

The essential function of exterior walls is to provide a continuous barrier to the exterior environmental conditions. The decay of the building facades is accelerated by atmospheric pollution and acidic precipitation. For determining of the impact of atmospheric pollution on the building facade face materials, the tests examining the impact of the cyclic moisturing‐drying have been carried out with the use of acidic water solution to imitate acidic rain. The results of the experiments demonstrated that water solutions have greater destructive effects on the paint film by penetrating through it into the plaster base, thus forming new derivatives in it, which increase water absorption in the plaster base. In order to improve the standard testing on weather resistance of facing building materials, which does not ignore the impact of the atmospheric pollution, for localities where acidic precipitations are frequent, the climatic tests should also include the deteriorating effect of acidic water solutions on facing materials. The results of the experiments will be used for a creation of the prognostic method which will lead to the establishment of a new accelerated climatic ageing test cycle meant for determining a more reliable prognosis of the durability of materials.