Recycling Bleach Technologies

1992 ◽  
Vol 266 ◽  
Author(s):  
James L. Minor

AbstractWhen faced with bleaching recycled fibers, the technologist must consider the usual factors associated with the bleaching of virgin fibers plus additional factors introduced by recycling. The lignin content of the furnish and the products to be made determine whether delignifying or lignin-preserving agents are to be used. Factors introduced by recycling include mixed lignin contents, dyes, residual ink particles and carrier chemicals, contaminants, color reversion, and hornification (which affects accessibility of chromophores to bleaching reagents). In addition, the technologist must be concerned with the environmental impact of the bleaching operation.Dithionite and formamidine sulfinic acid are effective lignin-preserving reductive bleaching agents for recycled fibers. Hydrogen peroxide is an effective lignin-preserving oxidative agent, but heavy metals and enzymes catalyze its decomposition. Chelating agents have an important role in decreasing metal content. For some delignification and effective removal of organic chromophores, oxygen and ozone show promise. Research on the use of oxygen-based oxidative bleaching agents is intense because of their favorable environmental attributes.

2007 ◽  
Vol 43 (4) ◽  
pp. 200-206 ◽  
Author(s):  
Alessia Cao ◽  
Alessandra Carucci ◽  
Tiziana Lai ◽  
Paolo La Colla ◽  
Elena Tamburini

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammad A. Jafar Mazumder ◽  
Panchami H. Raja ◽  
Arun M. Isloor ◽  
Muhammad Usman ◽  
Shakhawat H. Chowdhury ◽  
...  

2017 ◽  
Vol 17 (2) ◽  
pp. 131
Author(s):  
Emas Agus Prastyo Wibowo ◽  
Ika Sri Hardyanti ◽  
Isni Nurani ◽  
Dyan Septyaningsih Hardjono HP ◽  
Aden Dhana Rizkita

STUDI PENURUNAN KADAR LOGAM BESI (Fe) DAN LOGAM TEMBAGA (Cu) PADA AIR EMBUNG MENGGUNAKAN ADSORBEN NANOSILIKAABSTRAKPolusi limbah logam berat dalam air merupakan satu permasalahan lingkungan yang penting. Dalam mengatasi permasalahan tersebut dapat dilakukan purifikasi terhadap air tersebut. Metode yang dapat digunakan untuk purifikasi limbah sangat beragam salah satunya adalah absorpsi. Secara umum metode absorpsi telah banyak digunakan dalam purifikasi air limbah. Metode absorpsi dapat menurunkan kadar logam yang terlarut pada limbah. cair dengan cara menyerap logam-logam tersebut ke dalam permukaan absorbennya. Tujuan dilakukan penelitian ini adalah  untuk menurunkan konsentrasi logam besi (Fe) dan tembaga (Cu) menggunakan adsorben nanosilika. Penelitian ini menggunakan variabel bebas yaitu waktu pengadukan (20 menit, 40 menit, dan 60 menit). Hasil akhir filtrat air embung kemudian diukur absorbansinya menggunakan Spektrofotometer Serapan Atom. Berdasarkan hasil analisa menggunakan instrumen SSA diperoleh hasil bahwa tidak terjadi penurunan logam Fe maupun Cu. Dalam hal ini terjadi peningkatan konsentrasi dalam logam Fe maupun Cu, hal ini dikarenakan kurangnya waktu pengadukan dan pengaruh dari adsorben nanosilika.Kata Kunci: limbah, logam berat, nanosilika STUDY OF DECREASING METALS IRON (Fe) AND COPPER (Cu) ON EMBUNG WATER USE OF NANOSILICA ADSORBEN ABSTRACTHeavy waste pollution of heavy metals in the water is an important environment issue. To solve the problem, its can be purified the water. The methods that can be used for waste purification are very diverse, one of which is absorption. In general, the method of absorption has been widely used in wastewater purification. The absorption method can decrease dissolved metal content in the waste. liquid by absorbing the metals into the absorbent surface. Research has been conducted to reduce the concentration of iron (Fe) and copper (Cu) by using nanosilica adsorbent. This research used to independent variable that is stirring time (20 minutes, 40 minutes, and 60 minutes). The final result of filtrate embung water then measured its absorbance using Atomic Absorption Spectrophotometer (AAS). Based on the result of the analysis using SSA instrument, it is found that there is no decrease of Fe and Cu metals. There are several reasons for those problem such as due to lack of stirring time and the influence of nanosilica adsorbent.Keywords: Waste pollution, heavy metal, nanosilica


2021 ◽  
Author(s):  
Yang Lin ◽  
Kai Luo ◽  
Zilin Su ◽  
Yang Wu ◽  
Wei Xiao ◽  
...  

Abstract The urbanization is regarded as the major factor related to human activities that may interfere with the natural ecosystem. In this study, we have selected the wetland of East Dongting Lake as the research area. We have collected 180 soil samples (within the range of 0–20 cm, and 20cm-40cm), and we have measured the contents of their physicochemical properties (including salinity, pH value, soil particle composition, soil organic carbon, nitrate nitrogen and rapidly available phosphorus) as well as heavy metal elements (including As, Hg, Cd, Pb, Ni and Cr). We have adopted the methods of multivariate statistical analysis and inverse distance weighted (IDW) interpolation, so as to to reveal the sources and distribution characteristics of heavy metal content in soil in the research area. By adopting the potential ecological risk index (PERI) method proposed by Hakanson, we intend to assess the PERI values of heavy metals. Our research findings have shown that: (1) 8 sorts of heavy metals have shown positive correlation with each other. As, Hg and Zn have shown a significantly positive correlation with SOC (P < 0.01); As, Ni, Cr and Zn have shown a significantly positive correlation with AP (P < 0.01); As and Pb have shown a significantly positive correlation with Clay (P < 0.01); whereas Hg and Zn have shown a significantly negative correlation with Silt (P < 0.01); As and Pb have shown a significantly negative correlation with Sand (P < 0.01). (2) During urbanization, the elements of Cd, Ni, As, Hg and Pb might be enriched due to agricultural and industrial activities, whereas the use of fertilizers and pesticides constitute one of the major factors contributing to the increase of Cd and Pb contents in soil. (3) Influenced by the varying land patterns and with exception to Cu, the Fe-normalized concentrations have shown significant variations among different types of land use (P < 0.05). Specifically, there is a significantly higher level of Cd, Zn, Pb and Hg contents in the agricultural land than other types of land use, whereas there is a slightly higher level of heavy metal content in the mudflats than that in the grassland. In addition, the content of heavy metals in woodland remains relatively stable, and with exception to As, the content of heavy metals in woodland is the lowest among the five types of land. (4) The average value of the comprehensive PERI in heavy metals amounts to 555.03, representing a strong degree of ecological risks. Specifically, the proportion of sampling points of Cd that have a high level of ecological risks amounts to 36.51%, which is the primary element contributing to heavy metal pollution in the region, especially in the agricultural land.


2004 ◽  
Vol 4 (2) ◽  
pp. 58
Author(s):  
Lorraine A. Carrillo ◽  
Susan M. Gallardo

Wastewater treatment sludge, which is the largest volume residual waste stream generated by the pulp and paper industry, is generally disposed of in a dedicated landfill. Composting the sludge is an alternative method proposed by the Asian Regional Research Program on Environmental Technology-De La Salle University (ARRPET-DLSU) Minor Issue Group. The Philippine Department of Agriculture's (DA) standards for an organic fertilizer's maximum allowable content of heavy metals provided the legislative regulation for the conversion of sludge to compost. The research was designed to characterize the sludge samples from TIPCO, a Philippine paper-recycling mill, and establish whether the sludge contained the heavy metals cadmium, chromium, lead, mercury, nickel, and zinc using atomic absorption spectrophotometer (MS). Sampling was done for four weeks during newsprint and white paper production. Three discharge terminals were established as sampling points. The samples showed that the metal content of the sludge vary from point to point and was highest throughout the manufacture of white paper. Chromium, mercury, and nickel, however, were nondetectable in all the samples, while cadmium was detectable only in very few samples. Lead and zinc were present at all three points and were highest at the de inking sludge. Comparing the results with Part 503 of the United States EPA and the DA's guidelines for organic fertilizers yield significantly lower parameter values. Composting the sludge was, therefore, found to be a feasible option for recycling paper-mill sludge since the metal content were very low compared to local and international standards.


2021 ◽  
Vol 31 ◽  
pp. 00017
Author(s):  
Natalia Makeeva ◽  
Olga Neverova

The environmental effects of mining and its impact on natural resources are of a holistic nature. One of the modern methods employed for the remediation of technogenically disturbed soils is the application of microorganisms. This paper studies the impact made by soil microorganisms on the accumulation rate of heavy metals in the substrate of waste rock dumps in the process of soil reclamation. Suspensions of soil microorganisms (microorganisms utilising mineral nitrogen forms / MUMN; microorganisms decomposing silicates / MDS; microscopic fungi / MF) were applied to the rock dump surface. Separate groups as well as their combinations were applied. The heavy metal content analysis did not indicate a significant exceedance of the maximum allowable concentration limits (MACL) in the soil of the waste rock. The only metal whose content exceeded the maximum admissible concentration limits was nickel. It has found that the application of microorganisms influences the concentration of several heavy metals due to pH level changes of the rock dump soil.


1987 ◽  
Vol 26 ◽  
pp. 51-58
Author(s):  
Horas Hutagalung ◽  
Suwirma Syamsu

Determination of  heavy  metal  content  (Hg, Pb, Cd, Cu, Cr, Zn) in some seafoods collected from  Muara  Angke  Fish  Auction  Place  were carried out during February to July 1979. The results showed  that Zn  content  in seafoods a nalyzed  was always much higher than the other heavy metals. The concentration levels of  the  six  heavy  metals observed were low. It is almost of the same level as the metal concentration of  other  seafoods  observed  in various parts of the world oceans, but still lower  than the maximum standard set  for human  consumption  as  established  by   Tasmania, Australia and  World Health Organization. The  mean  per capita  consumption of  fish  in Jakarta is only  about 165 g  per week, while  the  Provisional Tolerated Weekly Intake for Hg, set by WHO/FAO at 300 ug level, would be attained by consuming 1500 g Rastrelliger sp., or 698 gPenaeus setiferus, or 545 g Sepia sp., and or 1250 g Pecten sp.  Therefore,  at   present the  level of metal content in fishes sold at TPI  Muara  Angke  can be  considered  as  not  dangerous  to human health as long as these quantities are not surpassed.


2021 ◽  
pp. 20-28
Author(s):  
Bartłomiej Igliński ◽  
Anna Iglińska ◽  
Urszula Kiełkowska ◽  
Dariusz Kamiński ◽  
Grzegorz Piechota

The metal content was determined using the WD-XRF method in the peat from the Wąpiersk bog and the Las Nadwelski bog (Welski Landscape Park, Poland). The results of the study show that the concentration of metals, especially heavy metals in peat bogs in Welski Landscape Park is low in general. In both bogs, the concentration of heavy metals was lower in the center than on the border. This shows that heavy metals are absorbed by the peat at the border and their further migration is limited. There are more elements such as iron, calcium and magnesium in the Las Nadwelski bog. There is more light on the border of the forest, which also plays an important role in decomposing plant debris, releasing metals. Heavy metals content was higher in Wąpiersk bog – a bog with higher anthropopressure. To sum up, the peat bog actively captures heavy metals, immobilizing them, and acts as a kind of “filter”. Peat is a good agent for retrospective monitoring of metals migration and accumulation in the environment.


2016 ◽  
Vol 11 (1) ◽  
pp. 9 ◽  
Author(s):  
Yani Permanawati ◽  
Rina Zuraida ◽  
Andrian Ibrahim

Penelitian Lingkungan dan Kebencanaan Geologi Kelautan Perairan Teluk Jakarta (Tanjung Kait – Muara Gembong) dilakukan pada bulan Oktober - November 2010. Uji logam berat (Cu, Pb, Zn, Cd, dan Cr) dilakukan terhadap 28 contoh air laut dan 28 contoh sedimen dasar laut menggunakan metoda Atomic Absorption Spectrophotometry (AAS). Tujuan penelitian ini adalah untuk mendapatkan data dan informasi kondisi lingkungan terkini dari kandungan logam berat dalam air laut dan sedimen dasar laut. Kandungan logam berat (air laut dalam mg/l : sedimen dasar laut dalam ppm) terukur sebagai berikut : Cu ( <0.005 : 15.000-169.500 ); Pb (0.005-0.011 : 14.000-58.100); Zn (0.005-0.007 : 95.800-333.000); Cd (0.006-0.015 : 0.012-0.750); Cr (<0.001 : 45.320-139.180). Berdasarkan Metode Storet dapat dilihat nilai status mutu air laut perairan ini adalah -12, berarti bahwa kualitas air laut di perairan termasuk kelas C (tercemar sedang). Sedangkan status mutu sedimen di perairan menunjukkan skor nilai status mutu sedimen adalah 0, yang berarti bahwa kualitas sedimen termasuk kelas A (tidak tercemar/memenuhi baku mutu). Jelas terlihat bahwa nilai ambang batas (NAB) logam berat dalam sedimen jauh lebih tinggi dari NAB logam berat dalam air. Kata kunci: logam berat, sedimen dasar laut, air laut, nilai status mutu Marine Environmental and Geological Hazard Survey In Jakarta Bay Waters (Tanjung Kait - Muara Gembong) conducted in October-November 2010. Testing of heavy metals (Cu, Pb, Zn, Cd, and Cr) performed on 28 samples of sea water and 28 subsurface sediment samples using the method of Atomic Absorption Spectrophotometry (AAS). The purpose of this study was to obtain data and information on current environmental conditions of heavy metal content in seawater and subsurface sediment. Heavy metal content (sea water in mg/l: subsurface sediment in ppm) measured as follows: Cu ( <0.005 : 15.000-169.500 ); Pb (0.005-0.011 : 14.000-58.100); Zn (0.005-0.007 : 95.800-333.000); Cd (0.006-0.015 : 0.012-0.750); Cr (<0.001 : 45.320-139.180). Based on the Storet method shows the value of water quality status of sea waters is -12, which means that the seawater quality in these waters belong to a class C (medium contaminated). While the status of sediment quality in these waters indicate subsurface sediment quality score status value is 0, which means that subsurface sediment quality belongs to the class A (not polluted/correspond to the quality standards). It is clearly seen that the threshold value (NAV) of heavy metals in sediments is much higher than the NAV of heavy metals in water. Keywords: heavy metal, subsurface sediment, seawater, quality score status


2012 ◽  
Vol 518-523 ◽  
pp. 5040-5046 ◽  
Author(s):  
Li Di Gao ◽  
Naoki Kano ◽  
Yuichi Sato ◽  
Shuang Zhang ◽  
Hiroshi Imaizumi

Effect of EDTA and EDDS on phytoremediation of Pb- and Zn- contaminated soil by Brassica Juncea was investigated in this work. Especially, the effect of the kind and the method of adding chelating agent was investigated during the plant growth. Plants were grown in an environmental control system. The biomass of the whole plant was weighed, and the uptake of Pb and Zn in shoot and root were determined using ICP-AES. Consequently, the following matters have been obtained: (1) Both EDTA and EDDS significantly enhanced the translocation of metals (Pb and Zn) in soil from root to shoot. Furthermore, the two chelating agents resulted in a sharply biomass loss for more than 30% of the control. As a result, the total uptake amount of metals by Brassica Juncea was decreased (except the uptake of Pb with the addition of 3.0 mmol•kg-1 EDTA). (2) EDDS showed the higher inhibition for the growth of Brassica Juncea than EDTA. (3) The method for adding EDTA and EDDS at several times separately did not necessarily increase the uptake of heavy metals.


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